Tesseract 3.02

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Public Member Functions | Protected Member Functions | Static Protected Member Functions | Protected Attributes
tesseract::TableFinder Class Reference

`#include <tablefind.h>`

List of all members.

## Public Member Functions
| TableFinder ()
| ~TableFinder ()
void | set_resolution (int resolution)
void | set_left_to_right_language (bool order)
void | Init (int grid_size, const ICOORD &bottom_left, const ICOORD &top_right)
void | InsertCleanPartitions (ColPartitionGrid *grid, TO_BLOCK *block)
void | LocateTables (ColPartitionGrid *grid, ColPartitionSet **columns, WidthCallback *width_cb, const FCOORD &reskew)

## Protected Member Functions
int | gridsize () const
int | gridwidth () const
int | gridheight () const
const ICOORD & | bleft () const
const ICOORD & | tright () const
ScrollView * | MakeWindow (int x, int y, const char *window_name)
void | InsertTextPartition (ColPartition *part)
void | InsertFragmentedTextPartition (ColPartition *part)
void | InsertLeaderPartition (ColPartition *part)
void | InsertRulingPartition (ColPartition *part)
void | InsertImagePartition (ColPartition *part)
void | SplitAndInsertFragmentedTextPartition (ColPartition *part)
bool | AllowTextPartition (const ColPartition &part) const
bool | AllowBlob (const BLOBNBOX &blob) const
void | MoveColSegmentsToGrid (ColSegment_LIST *segments, ColSegmentGrid *col_seg_grid)
void | InitializePartitions (ColPartitionSet **all_columns)
void | SetVerticalSpacing (ColPartition *part)
void | SetGlobalSpacings (ColPartitionGrid *grid)
void | set_global_median_xheight (int xheight)
void | set_global_median_blob_width (int width)
void | set_global_median_ledding (int ledding)
void | FindNeighbors ()
void | MarkTablePartitions ()
void | MarkPartitionsUsingLocalInformation ()
bool | HasWideOrNoInterWordGap (ColPartition *part) const
bool | HasLeaderAdjacent (const ColPartition &part)
void | FilterFalseAlarms ()
void | FilterParagraphEndings ()
void | FilterHeaderAndFooter ()
void | SmoothTablePartitionRuns ()
void | GetColumnBlocks (ColPartitionSet **columns, ColSegment_LIST *col_segments)
void | GroupColumnBlocks (ColSegment_LIST *current_segments, ColSegment_LIST *col_segments)
bool | ConsecutiveBoxes (const TBOX &b1, const TBOX &b2)
void | SetColumnsType (ColSegment_LIST *col_segments)
void | GridMergeColumnBlocks ()
void | GetTableColumns (ColSegment_LIST *table_columns)
void | GetTableRegions (ColSegment_LIST *table_columns, ColSegment_LIST *table_regions)
void | GridMergeTableRegions ()
bool | BelongToOneTable (const TBOX &box1, const TBOX &box2)
void | AdjustTableBoundaries ()
void | GrowTableBox (const TBOX &table_box, TBOX *result_box)
void | GrowTableToIncludePartials (const TBOX &table_box, const TBOX &search_range, TBOX *result_box)
void | GrowTableToIncludeLines (const TBOX &table_box, const TBOX &search_range, TBOX *result_box)
bool | HLineBelongsToTable (const ColPartition &part, const TBOX &table_box)
void | IncludeLeftOutColumnHeaders (TBOX *table_box)
void | DeleteSingleColumnTables ()
bool | GapInXProjection (int *xprojection, int length)
void | RecognizeTables ()
void | DisplayColSegments (ScrollView *win, ColSegment_LIST *cols, ScrollView::Color color)
void | DisplayColPartitions (ScrollView *win, ColPartitionGrid *grid, ScrollView::Color text_color, ScrollView::Color table_color)
void | DisplayColPartitions (ScrollView *win, ColPartitionGrid *grid, ScrollView::Color default_color)
void | DisplayColPartitionConnections (ScrollView *win, ColPartitionGrid *grid, ScrollView::Color default_color)
void | DisplayColSegmentGrid (ScrollView *win, ColSegmentGrid *grid, ScrollView::Color color)
void | WriteToPix (const FCOORD &reskew)
void | MakeTableBlocks (ColPartitionGrid *grid, ColPartitionSet **columns, WidthCallback *width_cb)

## Static Protected Member Functions
static void | SetPartitionSpacings (ColPartitionGrid *grid, ColPartitionSet **all_columns)

## Protected Attributes
int | resolution_
int | global_median_xheight_
int | global_median_blob_width_
int | global_median_ledding_
ColPartitionGrid | clean_part_grid_
ColPartitionGrid | leader_and_ruling_grid_
ColPartitionGrid | fragmented_text_grid_
ColSegmentGrid | col_seg_grid_
ColSegmentGrid | table_grid_
bool | left_to_right_language_

## Detailed Description

Definition at line 131 of file tablefind.h.

## Constructor & Destructor Documentation

tesseract::TableFinder::TableFinder | ( |  | ) |

Definition at line 168 of file tablefind.cpp.

: resolution_(0),
global_median_xheight_(0),
global_median_blob_width_(0),
global_median_ledding_(0),
left_to_right_language_(true) {
}

tesseract::TableFinder::~TableFinder | ( |  | ) |

Definition at line 176 of file tablefind.cpp.

{
// ColPartitions and ColSegments created by this class for storage in grids
// need to be deleted explicitly.
clean_part_grid_.ClearGridData(&DeleteObject<ColPartition>);
leader_and_ruling_grid_.ClearGridData(&DeleteObject<ColPartition>);
fragmented_text_grid_.ClearGridData(&DeleteObject<ColPartition>);
col_seg_grid_.ClearGridData(&DeleteObject<ColSegment>);
table_grid_.ClearGridData(&DeleteObject<ColSegment>);
}

## Member Function Documentation

void tesseract::TableFinder::AdjustTableBoundaries | ( |  | ) |
| protected

Definition at line 1485 of file tablefind.cpp.

{
// Iterate the table regions in the grid
ColSegment_CLIST adjusted_tables;
ColSegment_C_IT it(&adjusted_tables);
ColSegmentGridSearch gsearch(&table_grid_);
gsearch.StartFullSearch();
ColSegment* table = NULL;
while ((table = gsearch.NextFullSearch()) != NULL) {
const TBOX& table_box = table->bounding_box();
TBOX grown_box = table_box;
GrowTableBox(table_box, &grown_box);
// To prevent a table from expanding again, do not insert the
// modified box back to the grid. Instead move it to a list and
// and remove it from the grid. The list is moved later back to the grid.
if (!grown_box.null_box()) {
ColSegment* col = new ColSegment();
col->InsertBox(grown_box);
it.add_after_then_move(col);
}
gsearch.RemoveBBox();
delete table;
}
// clear table grid to move final tables in it
// TODO(nbeato): table_grid_ should already be empty. The above loop
// removed everything. Maybe just assert it is empty?
table_grid_.Clear();
it.move_to_first();
// move back final tables to table_grid_
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColSegment* seg = it.extract();
table_grid_.InsertBBox(true, true, seg);
}
}

bool tesseract::TableFinder::AllowBlob | ( | const BLOBNBOX & | blob | ) | const
| protected

Definition at line 502 of file tablefind.cpp.

{
const TBOX& box = blob.bounding_box();
const double kHeightRequired = global_median_xheight_ * kAllowBlobHeight;
const double kWidthRequired = global_median_blob_width_ * kAllowBlobWidth;
const int median_area = global_median_xheight_ * global_median_blob_width_;
const double kAreaRequired = median_area * kAllowBlobArea;
// Keep comparisons strictly greater to disallow 0!
return box.height() > kHeightRequired &&
box.width() > kWidthRequired &&
box.area() > kAreaRequired;
}

bool tesseract::TableFinder::AllowTextPartition | ( | const ColPartition & | part | ) | const
| protected

Definition at line 489 of file tablefind.cpp.

{
const double kHeightRequired = global_median_xheight_ * kAllowTextHeight;
const double kWidthRequired = global_median_blob_width_ * kAllowTextWidth;
const int median_area = global_median_xheight_ * global_median_blob_width_;
const double kAreaPerBlobRequired = median_area * kAllowTextArea;
// Keep comparisons strictly greater to disallow 0!
return part.median_size() > kHeightRequired &&
part.median_width() > kWidthRequired &&
part.bounding_box().area() > kAreaPerBlobRequired * part.boxes_count();
}

bool tesseract::TableFinder::BelongToOneTable | ( | const TBOX & | box1,
|  | const TBOX & | box2
| ) |  |
| protected

Definition at line 1444 of file tablefind.cpp.

{
// Check the obvious case. Most likely not true because overlapping boxes
// should already be merged, but seems like a good thing to do in case things
// change.
if (box1.overlap(box2))
return true;
// Check for ColPartitions spanning both table regions
TBOX bbox = box1.bounding_union(box2);
// Start a rect search on bbox
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
rectsearch(&clean_part_grid_);
rectsearch.StartRectSearch(bbox);
ColPartition* part = NULL;
while ((part = rectsearch.NextRectSearch()) != NULL) {
const TBOX& part_box = part->bounding_box();
// return true if a colpartition spanning both table regions is found
if (part_box.overlap(box1) && part_box.overlap(box2))
return true;
}
return false;
}

const ICOORD & tesseract::TableFinder::bleft | ( |  | ) | const
| protected

Definition at line 387 of file tablefind.cpp.

{
return clean_part_grid_.bleft();
}

bool tesseract::TableFinder::ConsecutiveBoxes | ( | const TBOX & | b1,
|  | const TBOX & | b2
| ) |  |
| protected

Definition at line 568 of file tablefind.cpp.

{
int x_margin = 20;
int y_margin = 5;
return (abs(b1.left() - b2.left()) < x_margin) &&
(abs(b1.right() - b2.right()) < x_margin) &&
(abs(b1.top()-b2.bottom()) < y_margin ||
abs(b2.top()-b1.bottom()) < y_margin);
}

void tesseract::TableFinder::DeleteSingleColumnTables | ( |  | ) |
| protected

Definition at line 1702 of file tablefind.cpp.

{
int page_width = tright().x() - bleft().x();
ASSERT_HOST(page_width > 0);
// create an integer array to hold projection on x-axis
int* table_xprojection = new int[page_width];
// Iterate through all tables in the table grid
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
table_search(&table_grid_);
table_search.StartFullSearch();
ColSegment* table;
while ((table = table_search.NextFullSearch()) != NULL) {
TBOX table_box = table->bounding_box();
// reset the projection array
for (int i = 0; i < page_width; i++) {
table_xprojection[i] = 0;
}
// Start a rect search on table_box
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
rectsearch(&clean_part_grid_);
rectsearch.SetUniqueMode(true);
rectsearch.StartRectSearch(table_box);
ColPartition* part;
while ((part = rectsearch.NextRectSearch()) != NULL) {
if (!part->IsTextType())
continue; // Do not consider non-text partitions
if (part->flow() == BTFT_LEADER)
continue; // Assume leaders are in tables
TBOX part_box = part->bounding_box();
// Do not consider partitions partially covered by the table
if (part_box.overlap_fraction(table_box) < kMinOverlapWithTable)
continue;
BLOBNBOX_CLIST* part_boxes = part->boxes();
BLOBNBOX_C_IT pit(part_boxes);
// Make sure overlapping blobs don't artificially inflate the number
// of rows in the table. This happens frequently with things such as
// decimals and split characters. Do this by assuming the column
// partition is sorted mostly left to right and just clip
// bounding boxes by the previous box's extent.
int next_position_to_write = 0;
for (pit.mark_cycle_pt(); !pit.cycled_list(); pit.forward()) {
BLOBNBOX *pblob = pit.data();
// ignore blob height for the purpose of projection since we
// are only interested in finding valleys
int xstart = pblob->bounding_box().left();
int xend = pblob->bounding_box().right();
xstart = MAX(xstart, next_position_to_write);
for (int i = xstart; i < xend; i++)
table_xprojection[i - bleft().x()]++;
next_position_to_write = xend;
}
}
// Find largest valley between two reasonable peaks in the table
if (!GapInXProjection(table_xprojection, page_width)) {
table_search.RemoveBBox();
delete table;
}
}
delete[] table_xprojection;
}

void tesseract::TableFinder::DisplayColPartitionConnections | ( | ScrollView * | win,
|  | ColPartitionGrid * | grid,
|  | ScrollView::Color | default_color
| ) |  |
| protected

Definition at line 1949 of file tablefind.cpp.

{
#ifndef GRAPHICS_DISABLED
// Iterate the ColPartitions in the grid.
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(grid);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
const TBOX& box = part->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
ColPartition* upper_part = part->nearest_neighbor_above();
if (upper_part) {
TBOX upper_box = upper_part->bounding_box();
int mid_x = (left_x + right_x) / 2;
int mid_y = (top_y + bottom_y) / 2;
int other_x = (upper_box.left() + upper_box.right()) / 2;
int other_y = (upper_box.top() + upper_box.bottom()) / 2;
win->Brush(ScrollView::NONE);
win->Pen(color);
win->Line(mid_x, mid_y, other_x, other_y);
}
ColPartition* lower_part = part->nearest_neighbor_below();
if (lower_part) {
TBOX lower_box = lower_part->bounding_box();
int mid_x = (left_x + right_x) / 2;
int mid_y = (top_y + bottom_y) / 2;
int other_x = (lower_box.left() + lower_box.right()) / 2;
int other_y = (lower_box.top() + lower_box.bottom()) / 2;
win->Brush(ScrollView::NONE);
win->Pen(color);
win->Line(mid_x, mid_y, other_x, other_y);
}
}
win->UpdateWindow();
#endif
}

void tesseract::TableFinder::DisplayColPartitions | ( | ScrollView * | win,
|  | ColPartitionGrid * | grid,
|  | ScrollView::Color | text_color,
|  | ScrollView::Color | table_color
| ) |  |
| protected

Definition at line 1915 of file tablefind.cpp.

{
#ifndef GRAPHICS_DISABLED
ScrollView::Color color = default_color;
// Iterate the ColPartitions in the grid.
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(grid);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
color = default_color;
if (part->type() == PT_TABLE)
color = table_color;
const TBOX& box = part->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
win->Brush(ScrollView::NONE);
win->Pen(color);
win->Rectangle(left_x, bottom_y, right_x, top_y);
}
win->UpdateWindow();
#endif
}

void tesseract::TableFinder::DisplayColPartitions | ( | ScrollView * | win,
|  | ColPartitionGrid * | grid,
|  | ScrollView::Color | default_color
| ) |  |
| protected

Definition at line 1943 of file tablefind.cpp.

{
DisplayColPartitions(win, grid, default_color, ScrollView::YELLOW);
}

void tesseract::TableFinder::DisplayColSegmentGrid | ( | ScrollView * | win,
|  | ColSegmentGrid * | grid,
|  | ScrollView::Color | color
| ) |  |
| protected

Definition at line 1890 of file tablefind.cpp.

{
#ifndef GRAPHICS_DISABLED
// Iterate the ColPartitions in the grid.
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
gsearch(grid);
gsearch.StartFullSearch();
ColSegment* seg = NULL;
while ((seg = gsearch.NextFullSearch()) != NULL) {
const TBOX& box = seg->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
win->Brush(ScrollView::NONE);
win->Pen(color);
win->Rectangle(left_x, bottom_y, right_x, top_y);
}
win->UpdateWindow();
#endif
}

void tesseract::TableFinder::DisplayColSegments | ( | ScrollView * | win,
|  | ColSegment_LIST * | cols,
|  | ScrollView::Color | color
| ) |  |
| protected

Definition at line 1870 of file tablefind.cpp.

{
#ifndef GRAPHICS_DISABLED
win->Pen(color);
win->Brush(ScrollView::NONE);
ColSegment_IT it(segments);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColSegment* col = it.data();
const TBOX& box = col->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
win->Rectangle(left_x, bottom_y, right_x, top_y);
}
win->UpdateWindow();
#endif
}

void tesseract::TableFinder::FilterFalseAlarms | ( |  | ) |
| protected

Definition at line 988 of file tablefind.cpp.

{
FilterParagraphEndings();
FilterHeaderAndFooter();
// TODO(nbeato): Fully justified text as non-table?
}

void tesseract::TableFinder::FilterHeaderAndFooter | ( |  | ) |
| protected

Definition at line 1074 of file tablefind.cpp.

{
// Consider top-most text colpartition as header and bottom most as footer
ColPartition* header = NULL;
ColPartition* footer = NULL;
int max_top = MIN_INT32;
int min_bottom = MAX_INT32;
ColPartitionGridSearch gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (!part->IsTextType())
continue; // Consider only text partitions
int top = part->bounding_box().top();
int bottom = part->bounding_box().bottom();
if (top > max_top) {
max_top = top;
header = part;
}
if (bottom < min_bottom) {
min_bottom = bottom;
footer = part;
}
}
if (header)
header->clear_table_type();
if (footer)
footer->clear_table_type();
}

void tesseract::TableFinder::FilterParagraphEndings | ( |  | ) |
| protected

Definition at line 994 of file tablefind.cpp.

{
// Detect last line of paragraph
// Iterate the ColPartitions in the grid.
ColPartitionGridSearch gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (part->type() != PT_TABLE)
continue; // Consider only table partitions
// Paragraph ending should have flowing text above it.
ColPartition* upper_part = part->nearest_neighbor_above();
if (!upper_part)
continue;
if (upper_part->type() != PT_FLOWING_TEXT)
continue;
if (upper_part->bounding_box().width() <
2 * part->bounding_box().width())
continue;
// Check if its the last line of a paragraph.
// In most cases, a paragraph ending should be left-aligned to text line
// above it. Sometimes, it could be a 2 line paragraph, in which case
// the line above it is indented.
// To account for that, check if the partition center is to
// the left of the one above it.
int mid = (part->bounding_box().left() + part->bounding_box().right()) / 2;
int upper_mid = (upper_part->bounding_box().left() +
upper_part->bounding_box().right()) / 2;
int current_spacing = 0; // spacing of the current line to margin
int upper_spacing = 0; // spacing of the previous line to the margin
if (left_to_right_language_) {
// Left to right languages, use mid - left to figure out the distance
// the middle is from the left margin.
int left = MIN(part->bounding_box().left(),
upper_part->bounding_box().left());
current_spacing = mid - left;
upper_spacing = upper_mid - left;
} else {
// Right to left languages, use right - mid to figure out the distance
// the middle is from the right margin.
int right = MAX(part->bounding_box().right(),
upper_part->bounding_box().right());
current_spacing = right - mid;
upper_spacing = right - upper_mid;
}
if (current_spacing * kParagraphEndingPreviousLineRatio > upper_spacing)
continue;
// Paragraphs should have similar fonts.
if (!part->MatchingSizes(*upper_part) ||
!part->MatchingStrokeWidth(*upper_part, kStrokeWidthFractionalTolerance,
kStrokeWidthConstantTolerance)) {
continue;
}
// The last line of a paragraph should be left aligned.
// TODO(nbeato): This would be untrue if the text was right aligned.
// How often is that?
if (part->space_to_left() >
kMaxParagraphEndingLeftSpaceMultiple * part->median_size())
continue;
// The line above it should be right aligned (assuming justified format).
// Since we can't assume justified text, we compare whitespace to text.
// The above line should have majority spanning text (or the current
// line could have fit on the previous line). So compare
// whitespace to text.
if (upper_part->bounding_box().width() <
kMinParagraphEndingTextToWhitespaceRatio * upper_part->space_to_right())
continue;
// Ledding above the line should be less than ledding below
if (part->space_above() >= part->space_below() ||
part->space_above() > 2 * global_median_ledding_)
continue;
// If all checks failed, it is probably text.
part->clear_table_type();
}
}

void tesseract::TableFinder::FindNeighbors | ( |  | ) |
| protected

Definition at line 766 of file tablefind.cpp.

{
ColPartitionGridSearch gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
// TODO(nbeato): Rename this function, meaning is different now.
// IT is finding nearest neighbors its own way
//SetVerticalSpacing(part);
ColPartition* upper = part->SingletonPartner(true);
if (upper)
part->set_nearest_neighbor_above(upper);
ColPartition* lower = part->SingletonPartner(false);
if (lower)
part->set_nearest_neighbor_below(lower);
}
}

bool tesseract::TableFinder::GapInXProjection | ( | int * | xprojection,
|  | int | length
| ) |  |
| protected

Definition at line 1767 of file tablefind.cpp.

{
// Find peak value of the histogram
int peak_value = 0;
for (int i = 0; i < length; i++) {
if (xprojection[i] > peak_value) {
peak_value = xprojection[i];
}
}
// Peak value represents the maximum number of horizontally
// overlapping colpartitions, so this can be considered as the
// number of rows in the table
if (peak_value < kMinRowsInTable)
return false;
double projection_threshold = kSmallTableProjectionThreshold * peak_value;
if (peak_value >= kLargeTableRowCount)
projection_threshold = kLargeTableProjectionThreshold * peak_value;
// Threshold the histogram
for (int i = 0; i < length; i++) {
xprojection[i] = (xprojection[i] >= projection_threshold) ? 1 : 0;
}
// Find the largest run of zeros between two ones
int largest_gap = 0;
int run_start = -1;
for (int i = 1; i < length; i++) {
// detect start of a run of zeros
if (xprojection[i - 1] && !xprojection[i]) {
run_start = i;
}
// detect end of a run of zeros and update the value of largest gap
if (run_start != -1 && !xprojection[i - 1] && xprojection[i]) {
int gap = i - run_start;
if (gap > largest_gap)
largest_gap = gap;
run_start = -1;
}
}
return largest_gap > kMaxXProjectionGapFactor * global_median_xheight_;
}

void tesseract::TableFinder::GetColumnBlocks | ( | ColPartitionSet ** | columns,
|  | ColSegment_LIST * | col_segments
| ) |  |
| protected

Definition at line 523 of file tablefind.cpp.

{
for (int i = 0; i < gridheight(); ++i) {
ColPartitionSet* columns = all_columns[i];
if (columns != NULL) {
ColSegment_LIST new_blocks;
// Get boxes from the current vertical position on the grid
columns->GetColumnBoxes(i * gridsize(), (i+1) * gridsize(), &new_blocks);
// Merge the new_blocks boxes into column_blocks if they are well-aligned
GroupColumnBlocks(&new_blocks, column_blocks);
}
}
}

void tesseract::TableFinder::GetTableColumns | ( | ColSegment_LIST * | table_columns | ) |
| protected

Definition at line 1273 of file tablefind.cpp.

{
ColSegment_IT it(table_columns);
// Iterate the ColPartitions in the grid.
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (part->inside_table_column() || part->type() != PT_TABLE)
continue; // prevent a partition to be assigned to multiple columns
const TBOX& box = part->bounding_box();
ColSegment* col = new ColSegment();
col->InsertBox(box);
part->set_inside_table_column(true);
// Start a search below the current cell to find bottom neighbours
// Note: a full search will always process things above it first, so
// this should be starting at the highest cell and working its way down.
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
vsearch(&clean_part_grid_);
vsearch.StartVerticalSearch(box.left(), box.right(), box.bottom());
ColPartition* neighbor = NULL;
bool found_neighbours = false;
while ((neighbor = vsearch.NextVerticalSearch(true)) != NULL) {
// only consider neighbors not assigned to any column yet
if (neighbor->inside_table_column())
continue;
// Horizontal lines should not break the flow
if (neighbor->IsHorizontalLine())
continue;
// presence of a non-table neighbor marks the end of current
// table column
if (neighbor->type() != PT_TABLE)
break;
// add the neighbor partition to the table column
const TBOX& neighbor_box = neighbor->bounding_box();
col->InsertBox(neighbor_box);
neighbor->set_inside_table_column(true);
found_neighbours = true;
}
if (found_neighbours) {
it.add_after_then_move(col);
} else {
part->set_inside_table_column(false);
delete col;
}
}
}

void tesseract::TableFinder::GetTableRegions | ( | ColSegment_LIST * | table_columns,
|  | ColSegment_LIST * | table_regions
| ) |  |
| protected

Definition at line 1323 of file tablefind.cpp.

{
ColSegment_IT cit(table_columns);
ColSegment_IT rit(table_regions);
// Iterate through column blocks
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
gsearch(&col_seg_grid_);
gsearch.StartFullSearch();
ColSegment* part;
int page_height = tright().y() - bleft().y();
ASSERT_HOST(page_height > 0);
// create a bool array to hold projection on y-axis
bool* table_region = new bool[page_height];
while ((part = gsearch.NextFullSearch()) != NULL) {
TBOX part_box = part->bounding_box();
// reset the projection array
for (int i = 0; i < page_height; i++) {
table_region[i] = false;
}
// iterate through all table columns to find regions in the current
// page column block
cit.move_to_first();
for (cit.mark_cycle_pt(); !cit.cycled_list(); cit.forward()) {
TBOX col_box = cit.data()->bounding_box();
// find intersection region of table column and page column
TBOX intersection_box = col_box.intersection(part_box);
// project table column on the y-axis
for (int i = intersection_box.bottom(); i < intersection_box.top(); i++) {
table_region[i - bleft().y()] = true;
}
}
// set x-limits of table regions to page column width
TBOX current_table_box;
current_table_box.set_left(part_box.left());
current_table_box.set_right(part_box.right());
// go through the y-axis projection to find runs of table
// regions. Each run makes one table region.
for (int i = 1; i < page_height; i++) {
// detect start of a table region
if (!table_region[i - 1] && table_region[i]) {
current_table_box.set_bottom(i + bleft().y());
}
// TODO(nbeato): Is it guaranteed that the last row is not a table region?
// detect end of a table region
if (table_region[i - 1] && !table_region[i]) {
current_table_box.set_top(i + bleft().y());
if (!current_table_box.null_box()) {
ColSegment* seg = new ColSegment();
seg->InsertBox(current_table_box);
rit.add_after_then_move(seg);
}
}
}
}
delete[] table_region;
}

int tesseract::TableFinder::gridheight | ( |  | ) | const
| protected

Definition at line 384 of file tablefind.cpp.

{
return clean_part_grid_.gridheight();
}

void tesseract::TableFinder::GridMergeColumnBlocks | ( |  | ) |
| protected

Definition at line 1195 of file tablefind.cpp.

{
int margin = gridsize();
// Iterate the Column Blocks in the grid.
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
gsearch(&col_seg_grid_);
gsearch.StartFullSearch();
ColSegment* seg;
while ((seg = gsearch.NextFullSearch()) != NULL) {
if (seg->type() != COL_TEXT)
continue; // only consider text blocks for split detection
bool neighbor_found = false;
bool modified = false; // Modified at least once
// keep expanding current box as long as neighboring table columns
// are found above or below it.
do {
TBOX box = seg->bounding_box();
// slightly expand the search region vertically
int top_range = MIN(box.top() + margin, tright().y());
int bottom_range = MAX(box.bottom() - margin, bleft().y());
box.set_top(top_range);
box.set_bottom(bottom_range);
neighbor_found = false;
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
rectsearch(&col_seg_grid_);
rectsearch.StartRectSearch(box);
ColSegment* neighbor = NULL;
while ((neighbor = rectsearch.NextRectSearch()) != NULL) {
if (neighbor == seg)
continue;
const TBOX& neighbor_box = neighbor->bounding_box();
// If the neighbor box significantly overlaps with the current
// box (due to the expansion of the current box in the
// previous iteration of this loop), remove the neighbor box
// and expand the current box to include it.
if (neighbor_box.overlap_fraction(box) >= 0.9) {
seg->InsertBox(neighbor_box);
modified = true;
rectsearch.RemoveBBox();
gsearch.RepositionIterator();
delete neighbor;
continue;
}
// Only expand if the neighbor box is of table type
if (neighbor->type() != COL_TABLE)
continue;
// Insert the neighbor box into the current column block
if (neighbor_box.major_x_overlap(box) &&
!box.contains(neighbor_box)) {
seg->InsertBox(neighbor_box);
neighbor_found = true;
modified = true;
rectsearch.RemoveBBox();
gsearch.RepositionIterator();
delete neighbor;
}
}
} while (neighbor_found);
if (modified) {
// Because the box has changed, it has to be removed first.
gsearch.RemoveBBox();
col_seg_grid_.InsertBBox(true, true, seg);
gsearch.RepositionIterator();
}
}
}

void tesseract::TableFinder::GridMergeTableRegions | ( |  | ) |
| protected

Definition at line 1386 of file tablefind.cpp.

{
// Iterate the table regions in the grid.
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
gsearch(&table_grid_);
gsearch.StartFullSearch();
ColSegment* seg = NULL;
while ((seg = gsearch.NextFullSearch()) != NULL) {
bool neighbor_found = false;
bool modified = false; // Modified at least once
do {
// Start a rectangle search x-bounded by the image and y by the table
const TBOX& box = seg->bounding_box();
TBOX search_region(box);
search_region.set_left(bleft().x());
search_region.set_right(tright().x());
neighbor_found = false;
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
rectsearch(&table_grid_);
rectsearch.StartRectSearch(search_region);
ColSegment* neighbor = NULL;
while ((neighbor = rectsearch.NextRectSearch()) != NULL) {
if (neighbor == seg)
continue;
const TBOX& neighbor_box = neighbor->bounding_box();
// Check if a neighbor box has a large overlap with the table
// region. This may happen as a result of merging two table
// regions in the previous iteration.
if (neighbor_box.overlap_fraction(box) >= 0.9) {
seg->InsertBox(neighbor_box);
rectsearch.RemoveBBox();
gsearch.RepositionIterator();
delete neighbor;
modified = true;
continue;
}
// Check if two table regions belong together based on a common
// horizontal ruling line
if (BelongToOneTable(box, neighbor_box)) {
seg->InsertBox(neighbor_box);
neighbor_found = true;
modified = true;
rectsearch.RemoveBBox();
gsearch.RepositionIterator();
delete neighbor;
}
}
} while (neighbor_found);
if (modified) {
// Because the box has changed, it has to be removed first.
gsearch.RemoveBBox();
table_grid_.InsertBBox(true, true, seg);
gsearch.RepositionIterator();
}
}
}

int tesseract::TableFinder::gridsize | ( |  | ) | const
| protected

Definition at line 378 of file tablefind.cpp.

{
return clean_part_grid_.gridsize();
}

int tesseract::TableFinder::gridwidth | ( |  | ) | const
| protected

Definition at line 381 of file tablefind.cpp.

{
return clean_part_grid_.gridwidth();
}

void tesseract::TableFinder::GroupColumnBlocks | ( | ColSegment_LIST * | current_segments,
|  | ColSegment_LIST * | col_segments
| ) |  |
| protected

Definition at line 538 of file tablefind.cpp.

{
ColSegment_IT src_it(new_blocks);
ColSegment_IT dest_it(column_blocks);
// iterate through the source list
for (src_it.mark_cycle_pt(); !src_it.cycled_list(); src_it.forward()) {
ColSegment* src_seg = src_it.data();
TBOX src_box = src_seg->bounding_box();
bool match_found = false;
// iterate through the destination list to find a matching column block
for (dest_it.mark_cycle_pt(); !dest_it.cycled_list(); dest_it.forward()) {
ColSegment* dest_seg = dest_it.data();
TBOX dest_box = dest_seg->bounding_box();
if (ConsecutiveBoxes(src_box, dest_box)) {
// If matching block is found, insert the current block into it
// and delete the soure block
dest_seg->InsertBox(src_box);
match_found = true;
delete src_it.extract();
break;
}
}
// If no match is found, just append the source block to column_blocks
if (!match_found) {
dest_it.add_after_then_move(src_it.extract());
}
}
}

void tesseract::TableFinder::GrowTableBox | ( | const TBOX & | table_box,
|  | TBOX * | result_box
| ) |  |
| protected

Definition at line 1519 of file tablefind.cpp.

{
// TODO(nbeato): The growing code is a bit excessive right now.
// By removing these lines, the partitions considered need
// to have some overlap or be special cases. These lines could
// be added again once a check is put in place to make sure that
// growing tables don't stomp on a lot of non-table partitions.
// search for horizontal ruling lines within the vertical margin
// int vertical_margin = kRulingVerticalMargin * gridsize();
TBOX search_box = table_box;
// int top = MIN(search_box.top() + vertical_margin, tright().y());
// int bottom = MAX(search_box.bottom() - vertical_margin, bleft().y());
// search_box.set_top(top);
// search_box.set_bottom(bottom);
GrowTableToIncludePartials(table_box, search_box, result_box);
GrowTableToIncludeLines(table_box, search_box, result_box);
IncludeLeftOutColumnHeaders(result_box);
}

void tesseract::TableFinder::GrowTableToIncludeLines | ( | const TBOX & | table_box,
|  | const TBOX & | search_range,
|  | TBOX * | result_box
| ) |  |
| protected

Definition at line 1569 of file tablefind.cpp.

{
ColPartitionGridSearch rsearch(&leader_and_ruling_grid_);
rsearch.SetUniqueMode(true);
rsearch.StartRectSearch(search_range);
ColPartition* part = NULL;
while ((part = rsearch.NextRectSearch()) != NULL) {
// TODO(nbeato) This should also do vertical, but column
// boundaries are breaking things. This function needs to be
// updated to allow vertical lines as well.
if (!part->IsLineType())
continue;
// Avoid the following function call if the result of the
// function is irrelevant.
const TBOX& part_box = part->bounding_box();
if (result_box->contains(part_box))
continue;
// Include a partially overlapping horizontal line only if the
// extra ColPartitions that will be included due to expansion
// have large side spacing w.r.t. columns containing them.
if (HLineBelongsToTable(*part, table_box))
*result_box = result_box->bounding_union(part_box);
// TODO(nbeato): Vertical
}
}

void tesseract::TableFinder::GrowTableToIncludePartials | ( | const TBOX & | table_box,
|  | const TBOX & | search_range,
|  | TBOX * | result_box
| ) |  |
| protected

Definition at line 1541 of file tablefind.cpp.

{
// Rulings are in a different grid, so search 2 grids for rulings, text,
// and table partitions that are not entirely within the new box.
for (int i = 0; i < 2; ++i) {
ColPartitionGrid* grid = (i == 0) ? &fragmented_text_grid_ :
&leader_and_ruling_grid_;
ColPartitionGridSearch rectsearch(grid);
rectsearch.StartRectSearch(search_range);
ColPartition* part = NULL;
while ((part = rectsearch.NextRectSearch()) != NULL) {
// Only include text and table types.
if (part->IsImageType())
continue;
const TBOX& part_box = part->bounding_box();
// Include partition in the table if more than half of it
// is covered by the table
if (part_box.overlap_fraction(table_box) > kMinOverlapWithTable) {
*result_box = result_box->bounding_union(part_box);
continue;
}
}
}
}

bool tesseract::TableFinder::HasLeaderAdjacent | ( | const ColPartition & | part | ) |
| protected

Definition at line 946 of file tablefind.cpp.

{
if (part.flow() == BTFT_LEADER)
return true;
// Search range is left and right bounded by an offset of the
// median xheight. This offset is to allow some tolerance to the
// the leaders on the page in the event that the alignment is still
// a bit off.
const TBOX& box = part.bounding_box();
const int search_size = kAdjacentLeaderSearchPadding * global_median_xheight_;
const int top = box.top() + search_size;
const int bottom = box.bottom() - search_size;
ColPartitionGridSearch hsearch(&leader_and_ruling_grid_);
for (int direction = 0; direction < 2; ++direction) {
bool right_to_left = (direction == 0);
int x = right_to_left ? box.right() : box.left();
hsearch.StartSideSearch(x, bottom, top);
ColPartition* leader = NULL;
while ((leader = hsearch.NextSideSearch(right_to_left)) != NULL) {
// This should not happen, they are in different grids.
ASSERT_HOST(&part != leader);
// The leader could be a horizontal ruling in the grid.
// Make sure it is actually a leader.
if (leader->flow() != BTFT_LEADER)
continue;
// Make sure the leader shares a page column with the partition,
// otherwise we are spreading across columns.
if (!part.IsInSameColumnAs(*leader))
break;
// There should be a significant vertical overlap
if (!leader->VSignificantCoreOverlap(part))
continue;
// Leader passed all tests, so it is adjacent.
return true;
}
}
// No leaders are adjacent to the given partition.
return false;
}

bool tesseract::TableFinder::HasWideOrNoInterWordGap | ( | ColPartition * | part | ) | const
| protected

Definition at line 857 of file tablefind.cpp.

{
// Should only get text partitions.
ASSERT_HOST(part->IsTextType());
// Blob access
BLOBNBOX_CLIST* part_boxes = part->boxes();
BLOBNBOX_C_IT it(part_boxes);
// Check if this is a relatively small partition (such as a single word)
if (part->bounding_box().width() <
kMinBoxesInTextPartition * part->median_size() &&
part_boxes->length() < kMinBoxesInTextPartition)
return true;
// Variables used to compute inter-blob spacing.
int current_x0 = -1;
int current_x1 = -1;
int previous_x1 = -1;
// Stores the maximum gap detected.
int largest_partition_gap_found = -1;
// Text partition gap limits. If this is text (and not a table),
// there should be at least one gap larger than min_gap and no gap
// larger than max_gap.
const double max_gap = kMaxGapInTextPartition * part->median_size();
const double min_gap = kMinMaxGapInTextPartition * part->median_size();
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
current_x0 = blob->bounding_box().left();
current_x1 = blob->bounding_box().right();
if (previous_x1 != -1) {
int gap = current_x0 - previous_x1;
// TODO(nbeato): Boxes may overlap? Huh?
// For example, mag.3B 8003_033.3B.tif in UNLV data. The titles/authors
// on the top right of the page are filtered out with this line.
// Note 2: Iterating over blobs in a partition, so we are looking for
// spacing between the words.
if (gap < 0) {
// More likely case, the blobs slightly overlap. This can happen
// with diacritics (accents) or broken alphabet symbols (characters).
// Merge boxes together by taking max of right sides.
if (-gap < part->median_size() * kMaxBlobOverlapFactor) {
previous_x1 = MAX(previous_x1, current_x1);
continue;
}
// Extreme case, blobs overlap significantly in the same partition...
// This should not happen often (if at all), but it does.
// TODO(nbeato): investigate cases when this happens.
else {
// The behavior before was to completely ignore this case.
}
}
// If a large enough gap is found, mark it as a table cell (return true)
if (gap > max_gap)
return true;
if (gap > largest_partition_gap_found)
largest_partition_gap_found = gap;
}
previous_x1 = current_x1;
}
// Since no large gap was found, return false if the partition is too
// long to be a data cell
if (part->bounding_box().width() >
kMaxBoxesInDataPartition * part->median_size() ||
part_boxes->length() > kMaxBoxesInDataPartition)
return false;
// A partition may be a single blob. In this case, it's an isolated symbol
// or non-text (such as a ruling or image).
// Detect these as table partitions? Shouldn't this be case by case?
// The behavior before was to ignore this, making max_partition_gap < 0
// and implicitly return true. Just making it explicit.
if (largest_partition_gap_found == -1)
return true;
// return true if the maximum gap found is smaller than the minimum allowed
// max_gap in a text partition. This indicates that there is no signficant
// space in the partition, hence it is likely a single word.
return largest_partition_gap_found < min_gap;
}

bool tesseract::TableFinder::HLineBelongsToTable | ( | const ColPartition & | part,
|  | const TBOX & | table_box
| ) |  |
| protected

Definition at line 1599 of file tablefind.cpp.

{
if (!part.IsHorizontalLine())
return false;
const TBOX& part_box = part.bounding_box();
if (!part_box.major_x_overlap(table_box))
return false;
// Do not consider top-most horizontal line since it usually
// originates from noise.
// TODO(nbeato): I had to comment this out because the ruling grid doesn't
// have neighbors solved.
// if (!part.nearest_neighbor_above())
// return false;
const TBOX bbox = part_box.bounding_union(table_box);
// In the "unioned table" box (the table extents expanded by the line),
// keep track of how many partitions have significant padding to the left
// and right. If more than half of the partitions covered by the new table
// have significant spacing, the line belongs to the table and the table
// grows to include all of the partitions.
int num_extra_partitions = 0;
int extra_space_to_right = 0;
int extra_space_to_left = 0;
// Rulings are in a different grid, so search 2 grids for rulings, text,
// and table partitions that are introduced by the new box.
for (int i = 0; i < 2; ++i) {
ColPartitionGrid* grid = (i == 0) ? &clean_part_grid_ :
&leader_and_ruling_grid_;
// Start a rect search on bbox
ColPartitionGridSearch rectsearch(grid);
rectsearch.SetUniqueMode(true);
rectsearch.StartRectSearch(bbox);
ColPartition* extra_part = NULL;
while ((extra_part = rectsearch.NextRectSearch()) != NULL) {
// ColPartition already in table
const TBOX& extra_part_box = extra_part->bounding_box();
if (extra_part_box.overlap_fraction(table_box) > kMinOverlapWithTable)
continue;
// Non-text ColPartitions do not contribute
if (extra_part->IsImageType())
continue;
// Consider this partition.
num_extra_partitions++;
// presence of a table cell is a strong hint, so just increment the scores
// without looking at the spacing.
if (extra_part->type() == PT_TABLE || extra_part->IsLineType()) {
extra_space_to_right++;
extra_space_to_left++;
continue;
}
int space_threshold = kSideSpaceMargin * part.median_size();
if (extra_part->space_to_right() > space_threshold)
extra_space_to_right++;
if (extra_part->space_to_left() > space_threshold)
extra_space_to_left++;
}
}
// tprintf("%d %d %d\n",
// num_extra_partitions,extra_space_to_right,extra_space_to_left);
return (extra_space_to_right > num_extra_partitions / 2) ||
(extra_space_to_left > num_extra_partitions / 2);
}

void tesseract::TableFinder::IncludeLeftOutColumnHeaders | ( | TBOX * | table_box | ) |
| protected

Definition at line 1663 of file tablefind.cpp.

{
// Start a search above the current table to look for column headers
ColPartitionGridSearch vsearch(&clean_part_grid_);
vsearch.StartVerticalSearch(table_box->left(), table_box->right(),
table_box->top());
ColPartition* neighbor = NULL;
ColPartition* previous_neighbor = NULL;
while ((neighbor = vsearch.NextVerticalSearch(false)) != NULL) {
// Max distance to find a table heading.
const int max_distance = kMaxColumnHeaderDistance *
neighbor->median_size();
int table_top = table_box->top();
const TBOX& box = neighbor->bounding_box();
// Do not continue if the next box is way above
if (box.bottom() - table_top > max_distance)
break;
// Unconditionally include partitions of type TABLE or LINE
// TODO(faisal): add some reasonable conditions here
if (neighbor->type() == PT_TABLE || neighbor->IsLineType()) {
table_box->set_top(box.top());
previous_neighbor = NULL;
continue;
}
// If there are two text partitions, one above the other, without a table
// cell on their left or right side, consider them a barrier and quit
if (previous_neighbor == NULL) {
previous_neighbor = neighbor;
} else {
const TBOX& previous_box = previous_neighbor->bounding_box();
if (!box.major_y_overlap(previous_box))
break;
}
}
}

void tesseract::TableFinder::Init | ( | int | grid_size,
|  | const ICOORD & | bottom_left,
|  | const ICOORD & | top_right
| ) |  |

Definition at line 190 of file tablefind.cpp.

{
// Initialize clean partitions list and grid
clean_part_grid_.Init(grid_size, bottom_left, top_right);
leader_and_ruling_grid_.Init(grid_size, bottom_left, top_right);
fragmented_text_grid_.Init(grid_size, bottom_left, top_right);
col_seg_grid_.Init(grid_size, bottom_left, top_right);
table_grid_.Init(grid_size, bottom_left, top_right);
}

void tesseract::TableFinder::InitializePartitions | ( | ColPartitionSet ** | all_columns | ) |
| protected

Definition at line 579 of file tablefind.cpp.

{
FindNeighbors();
SetPartitionSpacings(&clean_part_grid_, all_columns);
SetGlobalSpacings(&clean_part_grid_);
}

void tesseract::TableFinder::InsertCleanPartitions | ( | ColPartitionGrid * | grid,
|  | TO_BLOCK * | block
| ) |  |

Definition at line 202 of file tablefind.cpp.

{
// Calculate stats. This lets us filter partitions in AllowTextPartition()
// and filter blobs in AllowBlob().
SetGlobalSpacings(grid);
// Iterate the ColPartitions in the grid.
ColPartitionGridSearch gsearch(grid);
gsearch.SetUniqueMode(true);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
// Reject partitions with nothing useful inside of them.
if (part->blob_type() == BRT_NOISE || part->bounding_box().area() <= 0)
continue;
ColPartition* clean_part = part->ShallowCopy();
ColPartition* leader_part = NULL;
if (part->IsLineType()) {
InsertRulingPartition(clean_part);
continue;
}
// Insert all non-text partitions to clean_parts
if (!part->IsTextType()) {
InsertImagePartition(clean_part);
continue;
}
// Insert text colpartitions after removing noisy components from them
// The leaders are split into a separate grid.
BLOBNBOX_CLIST* part_boxes = part->boxes();
BLOBNBOX_C_IT pit(part_boxes);
for (pit.mark_cycle_pt(); !pit.cycled_list(); pit.forward()) {
BLOBNBOX *pblob = pit.data();
// Bad blobs... happens in UNLV set.
// news.3G1, page 17 (around x=6)
if (!AllowBlob(*pblob))
continue;
if (pblob->flow() == BTFT_LEADER) {
if (leader_part == NULL) {
leader_part = part->ShallowCopy();
leader_part->set_flow(BTFT_LEADER);
}
leader_part->AddBox(pblob);
} else if (pblob->region_type() != BRT_NOISE) {
clean_part->AddBox(pblob);
}
}
clean_part->ComputeLimits();
ColPartition* fragmented = clean_part->CopyButDontOwnBlobs();
InsertTextPartition(clean_part);
SplitAndInsertFragmentedTextPartition(fragmented);
if (leader_part != NULL) {
// TODO(nbeato): Note that ComputeLimits does not update the column
// information. So the leader may appear to span more columns than it
// really does later on when IsInSameColumnAs gets called to test
// for adjacent leaders.
leader_part->ComputeLimits();
InsertLeaderPartition(leader_part);
}
}
// Make the partition partners better for upper and lower neighbors.
clean_part_grid_.FindPartitionPartners();
clean_part_grid_.RefinePartitionPartners(false);
}

void tesseract::TableFinder::InsertFragmentedTextPartition | ( | ColPartition * | part | ) |
| protected

Definition at line 402 of file tablefind.cpp.

{
ASSERT_HOST(part != NULL);
if (AllowTextPartition(*part)) {
fragmented_text_grid_.InsertBBox(true, true, part);
} else {
delete part;
}
}

void tesseract::TableFinder::InsertImagePartition | ( | ColPartition * | part | ) |
| protected

Definition at line 421 of file tablefind.cpp.

{
// NOTE: If images are placed into a different grid in the future,
// the function SetPartitionSpacings needs to be updated. It should
// be the only thing that cares about image partitions.
clean_part_grid_.InsertBBox(true, true, part);
}

void tesseract::TableFinder::InsertLeaderPartition | ( | ColPartition * | part | ) |
| protected

Definition at line 410 of file tablefind.cpp.

{
ASSERT_HOST(part != NULL);
if (!part->IsEmpty() && part->bounding_box().area() > 0) {
leader_and_ruling_grid_.InsertBBox(true, true, part);
} else {
delete part;
}
}

void tesseract::TableFinder::InsertRulingPartition | ( | ColPartition * | part | ) |
| protected

Definition at line 418 of file tablefind.cpp.

{
leader_and_ruling_grid_.InsertBBox(true, true, part);
}

void tesseract::TableFinder::InsertTextPartition | ( | ColPartition * | part | ) |
| protected

Definition at line 394 of file tablefind.cpp.

{
ASSERT_HOST(part != NULL);
if (AllowTextPartition(*part)) {
clean_part_grid_.InsertBBox(true, true, part);
} else {
delete part;
}
}

void tesseract::TableFinder::LocateTables | ( | ColPartitionGrid * | grid,
|  | ColPartitionSet ** | columns,
|  | WidthCallback * | width_cb,
|  | const FCOORD & | reskew
| ) |  |

Definition at line 268 of file tablefind.cpp.

{
// initialize spacing, neighbors, and columns
InitializePartitions(all_columns);
if (textord_show_tables) {
ScrollView* table_win = MakeWindow(0, 300, "Column Partitions & Neighbors");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColPartitions(table_win, &leader_and_ruling_grid_,
ScrollView::AQUAMARINE);
DisplayColPartitionConnections(table_win, &clean_part_grid_,
ScrollView::ORANGE);
table_win = MakeWindow(100, 300, "Fragmented Text");
DisplayColPartitions(table_win, &fragmented_text_grid_, ScrollView::BLUE);
}
// mark, filter, and smooth candidate table partitions
MarkTablePartitions();
// Make single-column blocks from good_columns_ partitions. col_segments are
// moved to a grid later which takes the ownership
ColSegment_LIST column_blocks;
GetColumnBlocks(all_columns, &column_blocks);
// Set the ratio of candidate table partitions in each column
SetColumnsType(&column_blocks);
// Move column segments to col_seg_grid_
MoveColSegmentsToGrid(&column_blocks, &col_seg_grid_);
// Detect split in column layout that might have occurred due to the
// presence of a table. In such a case, merge the corresponding columns.
GridMergeColumnBlocks();
// Group horizontally overlapping table partitions into table columns.
// table_columns created here get deleted at the end of this method.
ColSegment_LIST table_columns;
GetTableColumns(&table_columns);
// Within each column, mark the range table regions occupy based on the
// table columns detected. table_regions are moved to a grid later which
// takes the ownership
ColSegment_LIST table_regions;
GetTableRegions(&table_columns, &table_regions);
if (textord_tablefind_show_mark) {
ScrollView* table_win = MakeWindow(1200, 300, "Table Columns and Regions");
DisplayColSegments(table_win, &table_columns, ScrollView::DARK_TURQUOISE);
DisplayColSegments(table_win, &table_regions, ScrollView::YELLOW);
}
// Merge table regions across columns for tables spanning multiple
// columns
MoveColSegmentsToGrid(&table_regions, &table_grid_);
GridMergeTableRegions();
// Adjust table boundaries by including nearby horizontal lines and left
// out column headers
AdjustTableBoundaries();
GridMergeTableRegions();
if (textord_tablefind_recognize_tables) {
// Remove false alarms consiting of a single column
DeleteSingleColumnTables();
if (textord_show_tables) {
ScrollView* table_win = MakeWindow(1200, 300, "Detected Table Locations");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColSegments(table_win, &table_columns, ScrollView::KHAKI);
table_grid_.DisplayBoxes(table_win);
}
// Find table grid structure and reject tables that are malformed.
RecognizeTables();
GridMergeTableRegions();
RecognizeTables();
if (textord_show_tables) {
ScrollView* table_win = MakeWindow(1400, 600, "Recognized Tables");
DisplayColPartitions(table_win, &clean_part_grid_,
ScrollView::BLUE, ScrollView::BLUE);
table_grid_.DisplayBoxes(table_win);
}
} else {
// Remove false alarms consiting of a single column
// TODO(nbeato): verify this is a NOP after structured table rejection.
// Right now it isn't. If the recognize function is doing what it is
// supposed to do, this function is obsolete.
DeleteSingleColumnTables();
if (textord_show_tables) {
ScrollView* table_win = MakeWindow(1500, 300, "Detected Tables");
DisplayColPartitions(table_win, &clean_part_grid_,
ScrollView::BLUE, ScrollView::BLUE);
table_grid_.DisplayBoxes(table_win);
}
}
if (textord_dump_table_images)
WriteToPix(reskew);
// Merge all colpartitions in table regions to make them a single
// colpartition and revert types of isolated table cells not
// assigned to any table to their original types.
MakeTableBlocks(grid, all_columns, width_cb);
}

void tesseract::TableFinder::MakeTableBlocks | ( | ColPartitionGrid * | grid,
|  | ColPartitionSet ** | columns,
|  | WidthCallback * | width_cb
| ) |  |
| protected

Definition at line 2070 of file tablefind.cpp.

{
// Since we have table blocks already, remove table tags from all
// colpartitions
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(grid);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (part->type() == PT_TABLE) {
part->clear_table_type();
}
}
// Now make a single colpartition out of each table block and remove
// all colpartitions contained within a table
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
table_search(&table_grid_);
table_search.StartFullSearch();
ColSegment* table;
while ((table = table_search.NextFullSearch()) != NULL) {
TBOX table_box = table->bounding_box();
// Start a rect search on table_box
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
rectsearch(grid);
rectsearch.StartRectSearch(table_box);
ColPartition* part;
ColPartition* table_partition = NULL;
while ((part = rectsearch.NextRectSearch()) != NULL) {
// Do not consider image partitions
if (!part->IsTextType())
continue;
TBOX part_box = part->bounding_box();
// Include partition in the table if more than half of it
// is covered by the table
if (part_box.overlap_fraction(table_box) > kMinOverlapWithTable) {
rectsearch.RemoveBBox();
if (table_partition) {
table_partition->Absorb(part, width_cb);
} else {
table_partition = part;
}
}
}
// Insert table colpartition back to part_grid_
if (table_partition) {
// To match the columns used when transforming to blocks, the new table
// partition must have its first and last column set at the grid y that
// corresponds to its bottom.
const TBOX& table_box = table_partition->bounding_box();
int grid_x, grid_y;
grid->GridCoords(table_box.left(), table_box.bottom(), &grid_x, &grid_y);
table_partition->SetPartitionType(resolution_, all_columns[grid_y]);
table_partition->set_table_type();
table_partition->set_blob_type(BRT_TEXT);
table_partition->set_flow(BTFT_CHAIN);
table_partition->SetBlobTypes();
grid->InsertBBox(true, true, table_partition);
}
}
}

ScrollView * tesseract::TableFinder::MakeWindow | ( | int | x,
|  | int | y,
|  | const char * | window_name
| ) |  |
| protected

Definition at line 518 of file tablefind.cpp.

{
return clean_part_grid_.MakeWindow(x, y, window_name);
}

void tesseract::TableFinder::MarkPartitionsUsingLocalInformation | ( |  | ) |
| protected

Definition at line 827 of file tablefind.cpp.

{
// Iterate the ColPartitions in the grid.
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (!part->IsTextType()) // Only consider text partitions
continue;
// Only consider partitions in dominant font size or smaller
if (part->median_size() > kMaxTableCellXheight * global_median_xheight_)
continue;
// Mark partitions with a large gap, or no significant gap as
// table partitions.
// Comments: It produces several false alarms at:
// - last line of a paragraph (fixed)
// - single word section headings
// - page headers and footers
// - numbered equations
// - line drawing regions
// TODO(faisal): detect and fix above-mentioned cases
if (HasWideOrNoInterWordGap(part) ||
HasLeaderAdjacent(*part)) {
part->set_table_type();
}
}
}

void tesseract::TableFinder::MarkTablePartitions | ( |  | ) |
| protected

Definition at line 789 of file tablefind.cpp.

{
MarkPartitionsUsingLocalInformation();
if (textord_tablefind_show_mark) {
ScrollView* table_win = MakeWindow(300, 300, "Initial Table Partitions");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColPartitions(table_win, &leader_and_ruling_grid_,
ScrollView::AQUAMARINE);
}
FilterFalseAlarms();
if (textord_tablefind_show_mark) {
ScrollView* table_win = MakeWindow(600, 300, "Filtered Table Partitions");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColPartitions(table_win, &leader_and_ruling_grid_,
ScrollView::AQUAMARINE);
}
SmoothTablePartitionRuns();
if (textord_tablefind_show_mark) {
ScrollView* table_win = MakeWindow(900, 300, "Smoothed Table Partitions");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColPartitions(table_win, &leader_and_ruling_grid_,
ScrollView::AQUAMARINE);
}
FilterFalseAlarms();
if (textord_tablefind_show_mark || textord_show_tables) {
ScrollView* table_win = MakeWindow(900, 300, "Final Table Partitions");
DisplayColPartitions(table_win, &clean_part_grid_, ScrollView::BLUE);
DisplayColPartitions(table_win, &leader_and_ruling_grid_,
ScrollView::AQUAMARINE);
}
}

void tesseract::TableFinder::MoveColSegmentsToGrid | ( | ColSegment_LIST * | segments,
|  | ColSegmentGrid * | col_seg_grid
| ) |  |
| protected

Definition at line 1176 of file tablefind.cpp.

{
ColSegment_IT it(segments);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColSegment* seg = it.extract();
col_seg_grid->InsertBBox(true, true, seg);
}
}

void tesseract::TableFinder::RecognizeTables | ( |  | ) |
| protected

Definition at line 1816 of file tablefind.cpp.

{
ScrollView* table_win = NULL;
if (textord_show_tables) {
table_win = MakeWindow(0, 0, "Table Structure");
DisplayColPartitions(table_win, &fragmented_text_grid_,
ScrollView::BLUE, ScrollView::LIGHT_BLUE);
// table_grid_.DisplayBoxes(table_win);
}
TableRecognizer recognizer;
recognizer.Init();
recognizer.set_line_grid(&leader_and_ruling_grid_);
recognizer.set_text_grid(&fragmented_text_grid_);
recognizer.set_max_text_height(global_median_xheight_ * 2.0);
recognizer.set_min_height(1.5 * gridheight());
// Loop over all of the tables and try to fit them.
// Store the good tables here.
ColSegment_CLIST good_tables;
ColSegment_C_IT good_it(&good_tables);
ColSegmentGridSearch gsearch(&table_grid_);
gsearch.StartFullSearch();
ColSegment* found_table = NULL;
while ((found_table = gsearch.NextFullSearch()) != NULL) {
gsearch.RemoveBBox();
// The goal is to make the tables persistent in a list.
// When that happens, this will move into the search loop.
const TBOX& found_box = found_table->bounding_box();
StructuredTable* table_structure = recognizer.RecognizeTable(found_box);
// Process a table. Good tables are inserted into the grid again later on
// We can't change boxes in the grid while it is running a search.
if (table_structure != NULL) {
if (textord_show_tables) {
table_structure->Display(table_win, ScrollView::LIME_GREEN);
}
found_table->set_bounding_box(table_structure->bounding_box());
delete table_structure;
good_it.add_after_then_move(found_table);
} else {
delete found_table;
}
}
// TODO(nbeato): MERGE!! There is awesome info now available for merging.
// At this point, the grid is empty. We can safely insert the good tables
// back into grid.
for (good_it.mark_cycle_pt(); !good_it.cycled_list(); good_it.forward())
table_grid_.InsertBBox(true, true, good_it.extract());
}

void tesseract::TableFinder::set_global_median_blob_width | ( | int | width | ) |
| protected

Definition at line 759 of file tablefind.cpp.

{
global_median_blob_width_ = width;
}

void tesseract::TableFinder::set_global_median_ledding | ( | int | ledding | ) |
| protected

Definition at line 762 of file tablefind.cpp.

{
global_median_ledding_ = ledding;
}

void tesseract::TableFinder::set_global_median_xheight | ( | int | xheight | ) |
| protected

Definition at line 756 of file tablefind.cpp.

{
global_median_xheight_ = xheight;
}

void tesseract::TableFinder::set_left_to_right_language | ( | bool | order | ) |

Definition at line 186 of file tablefind.cpp.

{
left_to_right_language_ = order;
}

void tesseract::TableFinder::set_resolution | ( | int | resolution | ) |
| inline

Definition at line 138 of file tablefind.h.

{
resolution_ = resolution;
}

void tesseract::TableFinder::SetColumnsType | ( | ColSegment_LIST * | col_segments | ) |
| protected

Definition at line 1143 of file tablefind.cpp.

{
ColSegment_IT it(column_blocks);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColSegment* seg = it.data();
TBOX box = seg->bounding_box();
int num_table_cells = 0;
int num_text_cells = 0;
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
rsearch(&clean_part_grid_);
rsearch.SetUniqueMode(true);
rsearch.StartRectSearch(box);
ColPartition* part = NULL;
while ((part = rsearch.NextRectSearch()) != NULL) {
if (part->type() == PT_TABLE) {
num_table_cells++;
} else if (part->type() == PT_FLOWING_TEXT) {
num_text_cells++;
}
}
// If a column block has no text or table partition in it, it is not needed
// for table detection.
if (!num_table_cells && !num_text_cells) {
delete it.extract();
} else {
seg->set_num_table_cells(num_table_cells);
seg->set_num_text_cells(num_text_cells);
// set column type based on the ratio of table to text cells
seg->set_type();
}
}
}

void tesseract::TableFinder::SetGlobalSpacings | ( | ColPartitionGrid * | grid | ) |
| protected

Definition at line 709 of file tablefind.cpp.

{
STATS xheight_stats(0, kMaxVerticalSpacing + 1);
STATS width_stats(0, kMaxBlobWidth + 1);
STATS ledding_stats(0, kMaxVerticalSpacing + 1);
// Iterate the ColPartitions in the grid.
ColPartitionGridSearch gsearch(grid);
gsearch.SetUniqueMode(true);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
// TODO(nbeato): HACK HACK HACK! medians are equal to partition length.
// ComputeLimits needs to get called somewhere outside of TableFinder
// to make sure the partitions are properly initialized.
// When this is called, SmoothPartitionPartners dies in an assert after
// table find runs. Alternative solution.
// part->ComputeLimits();
if (part->IsTextType()) {
// xheight_stats.add(part->median_size(), part->boxes_count());
// width_stats.add(part->median_width(), part->boxes_count());
// This loop can be removed when above issues are fixed.
// Replace it with the 2 lines commented out above.
BLOBNBOX_C_IT it(part->boxes());
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
xheight_stats.add(it.data()->bounding_box().height(), 1);
width_stats.add(it.data()->bounding_box().width(), 1);
}
ledding_stats.add(part->space_above(), 1);
ledding_stats.add(part->space_below(), 1);
}
}
// Set estimates based on median of statistics obtained
set_global_median_xheight(static_cast<int>(xheight_stats.median() + 0.5));
set_global_median_blob_width(static_cast<int>(width_stats.median() + 0.5));
set_global_median_ledding(static_cast<int>(ledding_stats.median() + 0.5));
#ifndef GRAPHICS_DISABLED
if (textord_tablefind_show_stats) {
const char* kWindowName = "X-height (R), X-width (G), and ledding (B)";
ScrollView* stats_win = MakeWindow(500, 10, kWindowName);
xheight_stats.plot(stats_win, 10, 200, 2, 15, ScrollView::RED);
width_stats.plot(stats_win, 10, 200, 2, 15, ScrollView::GREEN);
ledding_stats.plot(stats_win, 10, 200, 2, 15, ScrollView::BLUE);
}
#endif // GRAPHICS_DISABLED
}

void tesseract::TableFinder::SetPartitionSpacings | ( | ColPartitionGrid * | grid,
|  | ColPartitionSet ** | all_columns
| ) |  |
| static protected

Definition at line 586 of file tablefind.cpp.

{
// Iterate the ColPartitions in the grid.
ColPartitionGridSearch gsearch(grid);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
ColPartitionSet* columns = all_columns[gsearch.GridY()];
TBOX box = part->bounding_box();
int y = part->MidY();
ColPartition* left_column = columns->ColumnContaining(box.left(), y);
ColPartition* right_column = columns->ColumnContaining(box.right(), y);
// set distance from left column as space to the left
if (left_column) {
int left_space = MAX(0, box.left() - left_column->LeftAtY(y));
part->set_space_to_left(left_space);
}
// set distance from right column as space to the right
if (right_column) {
int right_space = MAX(0, right_column->RightAtY(y) - box.right());
part->set_space_to_right(right_space);
}
// Look for images that may be closer.
// NOTE: used to be part_grid_, might cause issues now
ColPartitionGridSearch hsearch(grid);
hsearch.StartSideSearch(box.left(), box.bottom(), box.top());
ColPartition* neighbor = NULL;
while ((neighbor = hsearch.NextSideSearch(true)) != NULL) {
if (neighbor->type() == PT_PULLOUT_IMAGE ||
neighbor->type() == PT_FLOWING_IMAGE ||
neighbor->type() == PT_HEADING_IMAGE) {
int right = neighbor->bounding_box().right();
if (right < box.left()) {
int space = MIN(box.left() - right, part->space_to_left());
part->set_space_to_left(space);
}
}
}
hsearch.StartSideSearch(box.left(), box.bottom(), box.top());
neighbor = NULL;
while ((neighbor = hsearch.NextSideSearch(false)) != NULL) {
if (neighbor->type() == PT_PULLOUT_IMAGE ||
neighbor->type() == PT_FLOWING_IMAGE ||
neighbor->type() == PT_HEADING_IMAGE) {
int left = neighbor->bounding_box().left();
if (left > box.right()) {
int space = MIN(left - box.right(), part->space_to_right());
part->set_space_to_right(space);
}
}
}
ColPartition* upper_part = part->SingletonPartner(true);
if (upper_part) {
int space = MAX(0, upper_part->bounding_box().bottom() -
part->bounding_box().bottom());
part->set_space_above(space);
} else {
// TODO(nbeato): What constitutes a good value?
// 0 is the default value when not set, explicitly noting it needs to
// be something else.
part->set_space_above(MAX_INT32);
}
ColPartition* lower_part = part->SingletonPartner(false);
if (lower_part) {
int space = MAX(0, part->bounding_box().bottom() -
lower_part->bounding_box().bottom());
part->set_space_below(space);
} else {
// TODO(nbeato): What constitutes a good value?
// 0 is the default value when not set, explicitly noting it needs to
// be something else.
part->set_space_below(MAX_INT32);
}
}
}

void tesseract::TableFinder::SetVerticalSpacing | ( | ColPartition * | part | ) |
| protected

Definition at line 666 of file tablefind.cpp.

{
TBOX box = part->bounding_box();
int top_range = MIN(box.top() + kMaxVerticalSpacing, tright().y());
int bottom_range = MAX(box.bottom() - kMaxVerticalSpacing, bleft().y());
box.set_top(top_range);
box.set_bottom(bottom_range);
TBOX part_box = part->bounding_box();
// Start a rect search
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
rectsearch(&clean_part_grid_);
rectsearch.StartRectSearch(box);
ColPartition* neighbor;
int min_space_above = kMaxVerticalSpacing;
int min_space_below = kMaxVerticalSpacing;
ColPartition* above_neighbor = NULL;
ColPartition* below_neighbor = NULL;
while ((neighbor = rectsearch.NextRectSearch()) != NULL) {
if (neighbor == part)
continue;
TBOX neighbor_box = neighbor->bounding_box();
if (neighbor_box.major_x_overlap(part_box)) {
int gap = abs(part->median_bottom() - neighbor->median_bottom());
// If neighbor is below current partition
if (neighbor_box.top() < part_box.bottom() &&
gap < min_space_below) {
min_space_below = gap;
below_neighbor = neighbor;
} // If neighbor is above current partition
else if (part_box.top() < neighbor_box.bottom() &&
gap < min_space_above) {
min_space_above = gap;
above_neighbor = neighbor;
}
}
}
part->set_space_above(min_space_above);
part->set_space_below(min_space_below);
part->set_nearest_neighbor_above(above_neighbor);
part->set_nearest_neighbor_below(below_neighbor);
}

void tesseract::TableFinder::SmoothTablePartitionRuns | ( |  | ) |
| protected

Definition at line 1108 of file tablefind.cpp.

{
// Iterate the ColPartitions in the grid.
ColPartitionGridSearch gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (part->type() >= PT_TABLE || part->type() == PT_UNKNOWN)
continue; // Consider only text partitions
ColPartition* upper_part = part->nearest_neighbor_above();
ColPartition* lower_part = part->nearest_neighbor_below();
if (!upper_part || !lower_part)
continue;
if (upper_part->type() == PT_TABLE && lower_part->type() == PT_TABLE)
part->set_table_type();
}
// Pass 2, do the opposite. If both the upper and lower neighbors
// exist and are not tables, this probably shouldn't be a table.
gsearch.StartFullSearch();
part = NULL;
while ((part = gsearch.NextFullSearch()) != NULL) {
if (part->type() != PT_TABLE)
continue; // Consider only text partitions
ColPartition* upper_part = part->nearest_neighbor_above();
ColPartition* lower_part = part->nearest_neighbor_below();
// table can't be by itself
if ((upper_part && upper_part->type() != PT_TABLE) &&
(lower_part && lower_part->type() != PT_TABLE)) {
part->clear_table_type();
}
}
}

void tesseract::TableFinder::SplitAndInsertFragmentedTextPartition | ( | ColPartition * | part | ) |
| protected

Definition at line 436 of file tablefind.cpp.

{
ASSERT_HOST(part != NULL);
// Bye bye empty partitions!
if (part->boxes()->empty()) {
delete part;
return;
}
// The AllowBlob function prevents this.
ASSERT_HOST(part->median_width() > 0);
const double kThreshold = part->median_width() * kSplitPartitionSize;
ColPartition* right_part = part;
bool found_split = true;
while (found_split) {
found_split = false;
BLOBNBOX_C_IT box_it(right_part->boxes());
// Blobs are sorted left side first. If blobs overlap,
// the previous blob may have a "more right" right side.
// Account for this by always keeping the largest "right"
// so far.
int previous_right = MIN_INT32;
// Look for the next split in the partition.
for (box_it.mark_cycle_pt(); !box_it.cycled_list(); box_it.forward()) {
const TBOX& box = box_it.data()->bounding_box();
if (previous_right != MIN_INT32 &&
box.left() - previous_right > kThreshold) {
// We have a split position. Split the partition in two pieces.
// Insert the left piece in the grid and keep processing the right.
int mid_x = (box.left() + previous_right) / 2;
ColPartition* left_part = right_part;
right_part = left_part->SplitAt(mid_x);
InsertFragmentedTextPartition(left_part);
found_split = true;
break;
}
// The right side of the previous blobs.
previous_right = MAX(previous_right, box.right());
}
}
// When a split is not found, the right part is minimized
// as much as possible, so process it.
InsertFragmentedTextPartition(right_part);
}

const ICOORD & tesseract::TableFinder::tright | ( |  | ) | const
| protected

Definition at line 390 of file tablefind.cpp.

{
return clean_part_grid_.tright();
}

void tesseract::TableFinder::WriteToPix | ( | const FCOORD & | reskew | ) |
| protected

Definition at line 1997 of file tablefind.cpp.

{
// Input file must be named test1.tif
PIX* pix = pixRead("test1.tif");
if (!pix) {
tprintf("Input file test1.tif not found.\n");
return;
}
int img_height = pixGetHeight(pix);
int img_width = pixGetWidth(pix);
// Maximum number of text or table partitions
int num_boxes = 10;
BOXA* text_box_array = boxaCreate(num_boxes);
BOXA* table_box_array = boxaCreate(num_boxes);
GridSearch<ColPartition, ColPartition_CLIST, ColPartition_C_IT>
gsearch(&clean_part_grid_);
gsearch.StartFullSearch();
ColPartition* part;
// load colpartitions into text_box_array and table_box_array
while ((part = gsearch.NextFullSearch()) != NULL) {
TBOX box = part->bounding_box();
box.rotate_large(reskew);
BOX* lept_box = boxCreate(box.left(), img_height - box.top(),
box.right() - box.left(),
box.top() - box.bottom());
if (part->type() == PT_TABLE)
boxaAddBox(table_box_array, lept_box, L_INSERT);
else
boxaAddBox(text_box_array, lept_box, L_INSERT);
}
// draw colpartitions on the output image
PIX* out = pixDrawBoxa(pix, text_box_array, 3, 0xff000000);
out = pixDrawBoxa(out, table_box_array, 3, 0x0000ff00);
BOXA* table_array = boxaCreate(num_boxes);
// text file containing detected table bounding boxes
FILE* fptr = fopen("tess-table.txt", "wb");
GridSearch<ColSegment, ColSegment_CLIST, ColSegment_C_IT>
table_search(&table_grid_);
table_search.StartFullSearch();
ColSegment* table;
// load table boxes to table_array and write them to text file as well
while ((table = table_search.NextFullSearch()) != NULL) {
TBOX box = table->bounding_box();
box.rotate_large(reskew);
// Since deskewing introduces negative coordinates, reskewing
// might not completely recover from that since both steps enlarge
// the actual box. Hence a box that undergoes deskewing/reskewing
// may go out of image boundaries. Crop a table box if needed to
// contain it inside the image dimensions.
box = box.intersection(TBOX(0, 0, img_width - 1, img_height - 1));
BOX* lept_box = boxCreate(box.left(), img_height - box.top(),
box.right() - box.left(),
box.top() - box.bottom());
boxaAddBox(table_array, lept_box, L_INSERT);
fprintf(fptr, "%d %d %d %d TABLE\n", box.left(),
img_height - box.top(), box.right(), img_height - box.bottom());
}
fclose(fptr);
// paint table boxes on the debug image
out = pixDrawBoxa(out, table_array, 5, 0x7fff0000);
pixWrite("out.png", out, IFF_PNG);
// memory cleanup
boxaDestroy(&text_box_array);
boxaDestroy(&table_box_array);
boxaDestroy(&table_array);
pixDestroy(&pix);
pixDestroy(&out);
}

## Member Data Documentation

ColPartitionGrid tesseract::TableFinder::clean_part_grid_
| protected

Definition at line 418 of file tablefind.h.

ColSegmentGrid tesseract::TableFinder::col_seg_grid_
| protected

Definition at line 426 of file tablefind.h.

ColPartitionGrid tesseract::TableFinder::fragmented_text_grid_
| protected

Definition at line 424 of file tablefind.h.

int tesseract::TableFinder::global_median_blob_width_
| protected

Definition at line 412 of file tablefind.h.

int tesseract::TableFinder::global_median_ledding_
| protected

Definition at line 414 of file tablefind.h.

int tesseract::TableFinder::global_median_xheight_
| protected

Definition at line 410 of file tablefind.h.

ColPartitionGrid tesseract::TableFinder::leader_and_ruling_grid_
| protected

Definition at line 420 of file tablefind.h.

bool tesseract::TableFinder::left_to_right_language_
| protected

Definition at line 430 of file tablefind.h.

int tesseract::TableFinder::resolution_
| protected

Definition at line 408 of file tablefind.h.

ColSegmentGrid tesseract::TableFinder::table_grid_
| protected

Definition at line 428 of file tablefind.h.

The documentation for this class was generated from the following files:

- /mnt/data/src/tesseract-ocr/textord/tablefind.h
- /mnt/data/src/tesseract-ocr/textord/tablefind.cpp