// Finds a vector corresponding to a set of vertically aligned blob edges
// running through the given box. The type of vector returned and the
// search parameters are determined by the AlignedBlobParams.
// vertical_x and y are updated with an estimate of the real
// vertical direction. (skew finding.)
// Returns NULL if no decent vector can be found.
TabVector* AlignedBlob::FindVerticalAlignment(AlignedBlobParams align_params,
BLOBNBOX* bbox,
int* vertical_x,
int* vertical_y) {
int ext_start_y, ext_end_y;
BLOBNBOX_CLIST good_points;
// Search up and then down from the starting bbox.
int pt_count = AlignTabs(align_params, false, bbox, &good_points, &ext_end_y);
pt_count += AlignTabs(align_params, true, bbox, &good_points, &ext_start_y);
BLOBNBOX_C_IT it(&good_points);
it.move_to_last();
int end_y = it.data()->bounding_box().top();
it.move_to_first();
int start_y = it.data()->bounding_box().bottom();
if (pt_count >= align_params.min_points &&
end_y - start_y >= align_params.min_length) {
int confirmed_points = 0;
// Count existing confirmed points to see if vector is acceptable.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
if (align_params.right_tab) {
if (bbox->right_tab_type() == align_params.confirmed_type)
++confirmed_points;
} else {
if (bbox->left_tab_type() == align_params.confirmed_type)
++confirmed_points;
}
}
// Ragged vectors are not allowed to use too many already used points.
if (!align_params.ragged ||
confirmed_points + confirmed_points < pt_count) {
const TBOX& box = bbox->bounding_box();
if (WithinTestRegion(2, box.left(), box.bottom())) {
tprintf("Confirming tab vector of %d pts starting at %d,%d\n",
pt_count, box.left(), box.bottom());
}
// Flag all the aligned neighbours as confirmed .
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
if (align_params.right_tab) {
bbox->set_right_tab_type(align_params.confirmed_type);
} else {
bbox->set_left_tab_type(align_params.confirmed_type);
}
}
// Now make the vector and return it.
TabVector* result = TabVector::FitVector(align_params.alignment,
align_params.vertical,
ext_start_y, ext_end_y,
&good_points,
vertical_x, vertical_y);
if (WithinTestRegion(2, box.left(), box.bottom())) {
result->Print("After fitting");
}
return result;
}
}
return NULL;
}
// Return the partner of this TabVector if the vector qualifies as
// being a vertical text line, otherwise NULL.
TabVector* TabVector::VerticalTextlinePartner() {
if (!partners_.singleton())
return NULL;
TabVector_C_IT partner_it(&partners_);
TabVector* partner = partner_it.data();
BLOBNBOX_C_IT box_it1(&boxes_);
BLOBNBOX_C_IT box_it2(&partner->boxes_);
// Count how many boxes are also in the other list.
// At the same time, gather the mean width and median vertical gap.
if (textord_debug_tabfind > 1) {
Print("Testing for vertical text");
partner->Print(" partner");
}
int num_matched = 0;
int num_unmatched = 0;
int total_widths = 0;
int width = startpt().x() - partner->startpt().x();
if (width < 0)
width = -width;
STATS gaps(0, width * 2);
BLOBNBOX* prev_bbox = NULL;
box_it2.mark_cycle_pt();
for (box_it1.mark_cycle_pt(); !box_it1.cycled_list(); box_it1.forward()) {
BLOBNBOX* bbox = box_it1.data();
TBOX box = bbox->bounding_box();
if (prev_bbox != NULL) {
gaps.add(box.bottom() - prev_bbox->bounding_box().top(), 1);
}
while (!box_it2.cycled_list() && box_it2.data() != bbox &&
box_it2.data()->bounding_box().bottom() < box.bottom()) {
box_it2.forward();
}
if (!box_it2.cycled_list() && box_it2.data() == bbox &&
bbox->region_type() >= BRT_UNKNOWN &&
(prev_bbox == NULL || prev_bbox->region_type() >= BRT_UNKNOWN))
++num_matched;
else
++num_unmatched;
total_widths += box.width();
prev_bbox = bbox;
}
if (num_unmatched + num_matched == 0) return NULL;
double avg_width = total_widths * 1.0 / (num_unmatched + num_matched);
double max_gap = textord_tabvector_vertical_gap_fraction * avg_width;
int min_box_match = static_cast<int>((num_matched + num_unmatched) *
textord_tabvector_vertical_box_ratio);
bool is_vertical = (gaps.get_total() > 0 &&
num_matched >= min_box_match &&
gaps.median() <= max_gap);
if (textord_debug_tabfind > 1) {
tprintf("gaps=%d, matched=%d, unmatched=%d, min_match=%d "
"median gap=%.2f, width=%.2f max_gap=%.2f Vertical=%s\n",
gaps.get_total(), num_matched, num_unmatched, min_box_match,
gaps.median(), avg_width, max_gap, is_vertical?"Yes":"No");
}
return (is_vertical) ? partner : NULL;
}
// Finds vertical lines in the given list of BLOBNBOXes. bleft and tright
// are the bounds of the image on which the input line_bblobs were found.
// The input line_bblobs list is const really.
// The output vertical_x and vertical_y are the total of all the vectors.
// The output list of TabVector makes no reference to the input BLOBNBOXes.
void LineFinder::FindLineVectors(const ICOORD& bleft, const ICOORD& tright,
BLOBNBOX_LIST* line_bblobs,
int* vertical_x, int* vertical_y,
TabVector_LIST* vectors) {
BLOBNBOX_IT bbox_it(line_bblobs);
int b_count = 0;
// Put all the blobs into the grid to find the lines, and move the blobs
// to the output lists.
AlignedBlob blob_grid(kLineFindGridSize, bleft, tright);
for (bbox_it.mark_cycle_pt(); !bbox_it.cycled_list(); bbox_it.forward()) {
BLOBNBOX* bblob = bbox_it.data();
bblob->set_left_tab_type(TT_UNCONFIRMED);
bblob->set_left_rule(bleft.x());
bblob->set_right_rule(tright.x());
bblob->set_left_crossing_rule(bleft.x());
bblob->set_right_crossing_rule(tright.x());
blob_grid.InsertBBox(false, true, bblob);
++b_count;
}
if (textord_debug_tabfind)
tprintf("Inserted %d line blobs into grid\n", b_count);
if (b_count == 0)
return;
// Search the entire grid, looking for vertical line vectors.
GridSearch<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT> lsearch(&blob_grid);
BLOBNBOX* bbox;
TabVector_IT vector_it(vectors);
*vertical_x = 0;
*vertical_y = 1;
lsearch.StartFullSearch();
while ((bbox = lsearch.NextFullSearch()) != NULL) {
if (bbox->left_tab_type() == TT_UNCONFIRMED) {
const TBOX& box = bbox->bounding_box();
if (AlignedBlob::WithinTestRegion(2, box.left(), box.bottom()))
tprintf("Finding line vector starting at bbox (%d,%d)\n",
box.left(), box.bottom());
AlignedBlobParams align_params(*vertical_x, *vertical_y, box.width());
TabVector* vector = blob_grid.FindVerticalAlignment(align_params, bbox,
vertical_x,
vertical_y);
if (vector != NULL) {
vector->Freeze();
vector_it.add_to_end(vector);
}
}
}
ScrollView* line_win = NULL;
if (textord_tabfind_show_vlines) {
line_win = blob_grid.MakeWindow(0, 50, "Vlines");
blob_grid.DisplayBoxes(line_win);
line_win = blob_grid.DisplayTabs("Vlines", line_win);
}
}
// Public factory to build a TabVector from a list of boxes.
// The TabVector will be of the given alignment type.
// The input vertical vector is used in fitting, and the output
// vertical_x, vertical_y have the resulting line vector added to them
// if the alignment is not ragged.
// The extended_start_y and extended_end_y are the maximum possible
// extension to the line segment that can be used to align with others.
// The input CLIST of BLOBNBOX good_points is consumed and taken over.
TabVector* TabVector::FitVector(TabAlignment alignment, ICOORD vertical,
int extended_start_y, int extended_end_y,
BLOBNBOX_CLIST* good_points,
int* vertical_x, int* vertical_y) {
TabVector* vector = new TabVector(extended_start_y, extended_end_y,
alignment, good_points);
if (!vector->Fit(vertical, false)) {
delete vector;
return NULL;
}
if (!vector->IsRagged()) {
vertical = vector->endpt_ - vector->startpt_;
int weight = vector->BoxCount();
*vertical_x += vertical.x() * weight;
*vertical_y += vertical.y() * weight;
}
return vector;
}
// Set all the tops and bottoms as appropriate to a mean of the
// constrained range. Delete all the constraints and list.
void TabConstraint::ApplyConstraints(TabConstraint_LIST* constraints) {
int y_min = -MAX_INT32;
int y_max = MAX_INT32;
GetConstraints(constraints, &y_min, &y_max);
int y = (y_min + y_max) / 2;
TabConstraint_IT it(constraints);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
TabConstraint* constraint = it.data();
TabVector* v = constraint->vector_;
if (constraint->is_top_) {
v->SetYEnd(y);
v->set_top_constraints(NULL);
} else {
v->SetYStart(y);
v->set_bottom_constraints(NULL);
}
}
delete constraints;
}
// Setup the constraints between the partners of this TabVector.
void TabVector::SetupPartnerConstraints() {
// With the first and last partner, we want a common bottom and top,
// respectively, and for each change of partner, we want a common
// top of first with bottom of next.
TabVector_C_IT it(&partners_);
TabVector* prev_partner = NULL;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
TabVector* partner = it.data();
if (partner->top_constraints_ == NULL ||
partner->bottom_constraints_ == NULL) {
partner->Print("Impossible: has no constraints");
Print("This vector has it as a partner");
continue;
}
if (prev_partner == NULL) {
// This is the first partner, so common bottom.
if (TabConstraint::CompatibleConstraints(bottom_constraints_,
partner->bottom_constraints_))
TabConstraint::MergeConstraints(bottom_constraints_,
partner->bottom_constraints_);
} else {
// We need prev top to be common with partner bottom.
if (TabConstraint::CompatibleConstraints(prev_partner->top_constraints_,
partner->bottom_constraints_))
TabConstraint::MergeConstraints(prev_partner->top_constraints_,
partner->bottom_constraints_);
}
prev_partner = partner;
if (it.at_last()) {
// This is the last partner, so common top.
if (TabConstraint::CompatibleConstraints(top_constraints_,
partner->top_constraints_))
TabConstraint::MergeConstraints(top_constraints_,
partner->top_constraints_);
}
}
}
// Return true if this vector is the same side, overlaps, and close
// enough to the other to be merged.
bool TabVector::SimilarTo(const ICOORD& vertical,
const TabVector& other, BlobGrid* grid) const {
if ((IsRightTab() && other.IsRightTab()) ||
(IsLeftTab() && other.IsLeftTab())) {
// If they don't overlap, at least in extensions, then there is no chance.
if (ExtendedOverlap(other.extended_ymax_, other.extended_ymin_) < 0)
return false;
// A fast approximation to the scale factor of the sort_key_.
int v_scale = abs(vertical.y());
if (v_scale == 0)
v_scale = 1;
// If they are close enough, then OK.
if (sort_key_ + kSimilarVectorDist * v_scale >= other.sort_key_ &&
sort_key_ - kSimilarVectorDist * v_scale <= other.sort_key_)
return true;
// Ragged tabs get a bigger threshold.
if (!IsRagged() || !other.IsRagged() ||
sort_key_ + kSimilarRaggedDist * v_scale < other.sort_key_ ||
sort_key_ - kSimilarRaggedDist * v_scale > other.sort_key_)
return false;
if (grid == NULL) {
// There is nothing else to test!
return true;
}
// If there is nothing in the rectangle between the vector that is going to
// move, and the place it is moving to, then they can be merged.
// Setup a vertical search for any blob.
const TabVector* mover = (IsRightTab() &&
sort_key_ < other.sort_key_) ? this : &other;
int top_y = mover->endpt_.y();
int bottom_y = mover->startpt_.y();
int left = MIN(mover->XAtY(top_y), mover->XAtY(bottom_y));
int right = MAX(mover->XAtY(top_y), mover->XAtY(bottom_y));
int shift = abs(sort_key_ - other.sort_key_) / v_scale;
if (IsRightTab()) {
right += shift;
} else {
left -= shift;
}
GridSearch<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT> vsearch(grid);
vsearch.StartVerticalSearch(left, right, top_y);
BLOBNBOX* blob;
while ((blob = vsearch.NextVerticalSearch(true)) != NULL) {
TBOX box = blob->bounding_box();
if (box.top() > bottom_y)
return true; // Nothing found.
if (box.bottom() < top_y)
continue; // Doesn't overlap.
int left_at_box = XAtY(box.bottom());
int right_at_box = left_at_box;
if (IsRightTab())
right_at_box += shift;
else
left_at_box -= shift;
if (MIN(right_at_box, box.right()) > MAX(left_at_box, box.left()))
return false;
}
return true; // Nothing found.
}
return false;
}
// Finds a vector corresponding to a set of vertically aligned blob edges
// running through the given box. The type of vector returned and the
// search parameters are determined by the AlignedBlobParams.
// vertical_x and y are updated with an estimate of the real
// vertical direction. (skew finding.)
// Returns nullptr if no decent vector can be found.
TabVector* AlignedBlob::FindVerticalAlignment(AlignedBlobParams align_params,
BLOBNBOX* bbox,
int* vertical_x,
int* vertical_y) {
int ext_start_y, ext_end_y;
BLOBNBOX_CLIST good_points;
// Search up and then down from the starting bbox.
TBOX box = bbox->bounding_box();
bool debug = WithinTestRegion(2, box.left(), box.bottom());
int pt_count = AlignTabs(align_params, false, bbox, &good_points, &ext_end_y);
pt_count += AlignTabs(align_params, true, bbox, &good_points, &ext_start_y);
BLOBNBOX_C_IT it(&good_points);
it.move_to_last();
box = it.data()->bounding_box();
int end_y = box.top();
int end_x = align_params.right_tab ? box.right() : box.left();
it.move_to_first();
box = it.data()->bounding_box();
int start_x = align_params.right_tab ? box.right() : box.left();
int start_y = box.bottom();
// Acceptable tab vectors must have a minimum number of points,
// have a minimum acceptable length, and have a minimum gradient.
// The gradient corresponds to the skew angle.
// Ragged tabs don't need to satisfy the gradient condition, as they
// will always end up parallel to the vertical direction.
bool at_least_2_crossings = AtLeast2LineCrossings(&good_points);
if ((pt_count >= align_params.min_points &&
end_y - start_y >= align_params.min_length &&
(align_params.ragged ||
end_y - start_y >= abs(end_x - start_x) * kMinTabGradient)) ||
at_least_2_crossings) {
int confirmed_points = 0;
// Count existing confirmed points to see if vector is acceptable.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
if (align_params.right_tab) {
if (bbox->right_tab_type() == align_params.confirmed_type)
++confirmed_points;
} else {
if (bbox->left_tab_type() == align_params.confirmed_type)
++confirmed_points;
}
}
// Ragged vectors are not allowed to use too many already used points.
if (!align_params.ragged ||
confirmed_points + confirmed_points < pt_count) {
const TBOX& box = bbox->bounding_box();
if (debug) {
tprintf("Confirming tab vector of %d pts starting at %d,%d\n",
pt_count, box.left(), box.bottom());
}
// Flag all the aligned neighbours as confirmed .
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
if (align_params.right_tab) {
bbox->set_right_tab_type(align_params.confirmed_type);
} else {
bbox->set_left_tab_type(align_params.confirmed_type);
}
if (debug) {
bbox->bounding_box().print();
}
}
// Now make the vector and return it.
TabVector* result = TabVector::FitVector(align_params.alignment,
align_params.vertical,
ext_start_y, ext_end_y,
&good_points,
vertical_x, vertical_y);
result->set_intersects_other_lines(at_least_2_crossings);
if (debug) {
tprintf("Box was %d, %d\n", box.left(), box.bottom());
result->Print("After fitting");
}
return result;
} else if (debug) {
tprintf("Ragged tab used too many used points: %d out of %d\n",
confirmed_points, pt_count);
}
} else if (debug) {
tprintf("Tab vector failed basic tests: pt count %d vs min %d, "
"length %d vs min %d, min grad %g\n",
pt_count, align_params.min_points, end_y - start_y,
align_params.min_length, abs(end_x - start_x) * kMinTabGradient);
}
return nullptr;
}
