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/******************************************************************************
*
* File: findseam.cpp (Formerly findseam.c)
* Author: Mark Seaman, OCR Technology
*
* (c) Copyright 1987, Hewlett-Packard Company.
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
** http://www.apache.org/licenses/LICENSE-2.0
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*
*****************************************************************************/
/*----------------------------------------------------------------------
I n c l u d e s
----------------------------------------------------------------------*/
#include "findseam.h"
#include "plotedges.h"
#include "outlines.h"
#include "seam.h"
#include "wordrec.h"
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
/**********************************************************************
* partial_split_priority
*
* Assign a priority to this split based on the features that it has.
* Grade it according to the different rating schemes and return the
* value of its goodness.
**********************************************************************/
#define partial_split_priority(split) \
(grade_split_length(split) + grade_sharpness(split))
/*----------------------------------------------------------------------
T y p e s
----------------------------------------------------------------------*/
#define SPLIT_CLOSENESS 20/* Difference in x value */
/* How many to keep */
#define MAX_NUM_SEAMS 150
/* How many to keep */
#define NO_FULL_PRIORITY -1/* Special marker for pri. */
/* Evaluate right away */
#define BAD_PRIORITY 9999.0
/*----------------------------------------------------------------------
F u n c t i o n s
----------------------------------------------------------------------*/
namespace tesseract {
/**********************************************************************
* add_seam_to_queue
*
* Adds the given new_seam to the seams priority queue, unless it is full
* and the new seam is worse than the worst.
**********************************************************************/
void Wordrec::add_seam_to_queue(float new_priority, SEAM *new_seam,
SeamQueue* seams) {
if (new_seam == nullptr) return;
if (chop_debug) {
tprintf("Pushing new seam with priority %g :", new_priority);
new_seam->Print("seam: ");
}
if (seams->size() >= MAX_NUM_SEAMS) {
SeamPair old_pair(0, nullptr);
if (seams->PopWorst(&old_pair) && old_pair.key() <= new_priority) {
if (chop_debug) {
tprintf("Old seam staying with priority %g\n", old_pair.key());
}
delete new_seam;
seams->Push(&old_pair);
return;
} else if (chop_debug) {
tprintf("New seam with priority %g beats old worst seam with %g\n",
new_priority, old_pair.key());
}
}
SeamPair new_pair(new_priority, new_seam);
seams->Push(&new_pair);
}
/**********************************************************************
* choose_best_seam
*
* Choose the best seam that can be created by assembling this a
* collection of splits. A queue of all the possible seams is
* maintained. Each new split received is placed in that queue with
* its partial priority value. These values in the seam queue are
* evaluated and combined until a good enough seam is found. If no
* further good seams are being found then this function returns to the
* caller, who will send more splits. If this function is called with
* a split of nullptr, then no further splits can be supplied by the
* caller.
**********************************************************************/
void Wordrec::choose_best_seam(SeamQueue *seam_queue, const SPLIT *split,
PRIORITY priority, SEAM **seam_result,
TBLOB *blob, SeamPile *seam_pile) {
SEAM *seam;
char str[80];
float my_priority;
/* Add seam of split */
my_priority = priority;
if (split != nullptr) {
TPOINT split_point = split->point1->pos;
split_point += split->point2->pos;
split_point /= 2;
seam = new SEAM(my_priority, split_point, *split);
if (chop_debug > 1) seam->Print("Partial priority ");
add_seam_to_queue(my_priority, seam, seam_queue);
if (my_priority > chop_good_split)
return;
}
TBOX bbox = blob->bounding_box();
/* Queue loop */
while (!seam_queue->empty()) {
SeamPair seam_pair;
seam_queue->Pop(&seam_pair);
seam = seam_pair.extract_data();
/* Set full priority */
my_priority = seam->FullPriority(bbox.left(), bbox.right(),
chop_overlap_knob, chop_centered_maxwidth,
chop_center_knob, chop_width_change_knob);
if (chop_debug) {
sprintf (str, "Full my_priority %0.0f, ", my_priority);
seam->Print(str);
}
if ((*seam_result == nullptr || (*seam_result)->priority() > my_priority) &&
my_priority < chop_ok_split) {
/* No crossing */
if (seam->IsHealthy(*blob, chop_min_outline_points,
chop_min_outline_area)) {
delete *seam_result;
*seam_result = new SEAM(*seam);
(*seam_result)->set_priority(my_priority);
} else {
delete seam;
seam = nullptr;
my_priority = BAD_PRIORITY;
}
}
if (my_priority < chop_good_split) {
delete seam;
return; /* Made good answer */
}
if (seam) {
/* Combine with others */
if (seam_pile->size() < chop_seam_pile_size) {
combine_seam(*seam_pile, seam, seam_queue);
SeamDecPair pair(seam_pair.key(), seam);
seam_pile->Push(&pair);
} else if (chop_new_seam_pile &&
seam_pile->size() == chop_seam_pile_size &&
seam_pile->PeekTop().key() > seam_pair.key()) {
combine_seam(*seam_pile, seam, seam_queue);
SeamDecPair pair;
seam_pile->Pop(&pair); // pop the worst.
// Replace the seam in pair (deleting the old one) with
// the new seam and score, then push back into the heap.
pair.set_key(seam_pair.key());
pair.set_data(seam);
seam_pile->Push(&pair);
} else {
delete seam;
}
}
my_priority = seam_queue->empty() ? NO_FULL_PRIORITY
: seam_queue->PeekTop().key();
if ((my_priority > chop_ok_split) ||
(my_priority > chop_good_split && split))
return;
}
}
/**********************************************************************
* combine_seam
*
* Find other seams to combine with this one. The new seams that result
* from this union should be added to the seam queue. The return value
* tells whether or not any additional seams were added to the queue.
**********************************************************************/
void Wordrec::combine_seam(const SeamPile& seam_pile,
const SEAM* seam, SeamQueue* seam_queue) {
for (int x = 0; x < seam_pile.size(); ++x) {
const SEAM *this_one = seam_pile.get(x).data();
if (seam->CombineableWith(*this_one, SPLIT_CLOSENESS, chop_ok_split)) {
SEAM *new_one = new SEAM(*seam);
new_one->CombineWith(*this_one);
if (chop_debug > 1) new_one->Print("Combo priority ");
add_seam_to_queue(new_one->priority(), new_one, seam_queue);
}
}
}
/**********************************************************************
* pick_good_seam
*
* Find and return a good seam that will split this blob into two pieces.
* Work from the outlines provided.
**********************************************************************/
SEAM *Wordrec::pick_good_seam(TBLOB *blob) {
SeamPile seam_pile(chop_seam_pile_size);
EDGEPT *points[MAX_NUM_POINTS];
EDGEPT_CLIST new_points;
SEAM *seam = nullptr;
TESSLINE *outline;
int16_t num_points = 0;
#ifndef GRAPHICS_DISABLED
if (chop_debug > 2)
wordrec_display_splits.set_value(true);
draw_blob_edges(blob);
#endif
PointHeap point_heap(MAX_NUM_POINTS);
for (outline = blob->outlines; outline; outline = outline->next)
prioritize_points(outline, &point_heap);
while (!point_heap.empty() && num_points < MAX_NUM_POINTS) {
points[num_points++] = point_heap.PeekTop().data();
point_heap.Pop(nullptr);
}
/* Initialize queue */
SeamQueue seam_queue(MAX_NUM_SEAMS);
try_point_pairs(points, num_points, &seam_queue, &seam_pile, &seam, blob);
try_vertical_splits(points, num_points, &new_points,
&seam_queue, &seam_pile, &seam, blob);
if (seam == nullptr) {
choose_best_seam(&seam_queue, nullptr, BAD_PRIORITY, &seam, blob, &seam_pile);
} else if (seam->priority() > chop_good_split) {
choose_best_seam(&seam_queue, nullptr, seam->priority(), &seam, blob,
&seam_pile);
}
EDGEPT_C_IT it(&new_points);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
EDGEPT *inserted_point = it.data();
if (seam == nullptr || !seam->UsesPoint(inserted_point)) {
for (outline = blob->outlines; outline; outline = outline->next) {
if (outline->loop == inserted_point) {
outline->loop = outline->loop->next;
}
}
remove_edgept(inserted_point);
}
}
if (seam) {
if (seam->priority() > chop_ok_split) {
delete seam;
seam = nullptr;
}
#ifndef GRAPHICS_DISABLED
else if (wordrec_display_splits) {
seam->Mark(edge_window);
if (chop_debug > 2) {
edge_window->Update();
edge_window->Wait();
}
}
#endif
}
if (chop_debug)
wordrec_display_splits.set_value(false);
return (seam);
}
/**********************************************************************
* try_point_pairs
*
* Try all the splits that are produced by pairing critical points
* together. See if any of them are suitable for use. Use a seam
* queue and seam pile that have already been initialized and used.
**********************************************************************/
void Wordrec::try_point_pairs(EDGEPT * points[MAX_NUM_POINTS],
int16_t num_points,
SeamQueue* seam_queue,
SeamPile* seam_pile,
SEAM ** seam,
TBLOB * blob) {
int16_t x;
int16_t y;
PRIORITY priority;
for (x = 0; x < num_points; x++) {
for (y = x + 1; y < num_points; y++) {
if (points[y] &&
points[x]->WeightedDistance(*points[y], chop_x_y_weight) <
chop_split_length &&
points[x] != points[y]->next && points[y] != points[x]->next &&
!is_exterior_point(points[x], points[y]) &&
!is_exterior_point(points[y], points[x])) {
SPLIT split(points[x], points[y]);
priority = partial_split_priority(&split);
choose_best_seam(seam_queue, &split, priority, seam, blob, seam_pile);
}
}
}
}
/**********************************************************************
* try_vertical_splits
*
* Try all the splits that are produced by vertical projection to see
* if any of them are suitable for use. Use a seam queue and seam pile
* that have already been initialized and used.
* Return in new_points a collection of points that were inserted into
* the blob while examining vertical splits and which may safely be
* removed once a seam is chosen if they are not part of the seam.
**********************************************************************/
void Wordrec::try_vertical_splits(EDGEPT * points[MAX_NUM_POINTS],
int16_t num_points,
EDGEPT_CLIST *new_points,
SeamQueue* seam_queue,
SeamPile* seam_pile,
SEAM ** seam,
TBLOB * blob) {
EDGEPT *vertical_point = nullptr;
int16_t x;
PRIORITY priority;
TESSLINE *outline;
for (x = 0; x < num_points; x++) {
vertical_point = nullptr;
for (outline = blob->outlines; outline; outline = outline->next) {
vertical_projection_point(points[x], outline->loop,
&vertical_point, new_points);
}
if (vertical_point && points[x] != vertical_point->next &&
vertical_point != points[x]->next &&
points[x]->WeightedDistance(*vertical_point, chop_x_y_weight) <
chop_split_length) {
SPLIT split(points[x], vertical_point);
priority = partial_split_priority(&split);
choose_best_seam(seam_queue, &split, priority, seam, blob, seam_pile);
}
}
}
}
|