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// Intel License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000, Intel Corporation, all rights reserved.
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//M*/
#include "_cvaux.h"
#ifdef WIN32 /* make sure it builds under Linux whenever it is included into Makefile.am or not. */
//void icvCutContour( CvSeq* current, IplImage* image );
CvSeq* icvCutContourRaster( CvSeq* current, CvMemStorage* storage, IplImage* image );
//create lists of segments of all contours from image
CvSeq* cvExtractSingleEdges( IplImage* image, //bw image - it's content will be destroyed by cvFindContours
CvMemStorage* storage )
{
CvMemStorage* tmp_storage = cvCreateChildMemStorage( storage );
CvSeq* contours = 0;
cvFindContours( image, tmp_storage, &contours, sizeof(CvContour), CV_RETR_LIST, CV_CHAIN_APPROX_NONE );
cvZero( image );
//iterate through contours
//iterate through tree
CvSeq* current = contours;
int number = 0;
int level = 1;
CvSeq* output = 0;
CvSeq* tail_seq = 0;
//actually this loop can iterates through tree,
//but still we use CV_RETR_LIST it is not useful
while( current )
{
number++;
//get vertical list of segments for one contour
CvSeq* new_seq = icvCutContourRaster( current, storage, image );
//add this vertical list to horisontal list
if( new_seq )
{
if( tail_seq )
{
tail_seq->h_next = new_seq;
new_seq->h_prev = tail_seq;
tail_seq = new_seq;
}
else
{
output = tail_seq = new_seq;
}
}
//iteration through tree
if( current->v_next )
{
//goto child
current = current->v_next;
level++;
}
else
{
//go parent
while( !current->h_next )
{
current = current->v_prev;
level--;
if( !level ) break;
}
if( current ) //go brother
current = current->h_next;
}
}
//free temporary memstorage with initial contours
cvReleaseMemStorage( &tmp_storage );
return output;
}
//makes vertical list of segments for 1 contour
CvSeq* icvCutContourRaster( CvSeq* current, CvMemStorage* storage, IplImage* image /*tmp image*/)
{
//iplSet(image, 0 ); // this can cause double edges if two contours have common edge
// for example if object is circle with 1 pixel width
// to remove such problem - remove this iplSet
//approx contour by single edges
CvSeqReader reader;
CvSeqWriter writer;
int writing = 0;
cvStartReadSeq( current, &reader, 0 );
//below line just to avoid warning
cvStartWriteSeq( current->flags, sizeof(CvContour), sizeof(CvPoint), storage, &writer );
CvSeq* output = 0;
CvSeq* tail = 0;
//first pass through contour - compute number of branches at every point
int i;
for( i = 0; i < current->total; i++ )
{
CvPoint cur;
CV_READ_SEQ_ELEM( cur, reader );
//mark point
((uchar*)image->imageData)[image->widthStep * cur.y + cur.x]++;
assert( ((uchar*)image->imageData)[image->widthStep * cur.y + cur.x] != 255 );
}
//second pass - create separate edges
for( i = 0; i < current->total; i++ )
{
CvPoint cur;
CV_READ_SEQ_ELEM( cur, reader );
//get pixel at this point
uchar flag = image->imageData[image->widthStep * cur.y + cur.x];
if( flag != 255 && flag < 3) //
{
if(!writing)
{
cvStartWriteSeq( current->flags, sizeof(CvContour), sizeof(CvPoint), storage, &writer );
writing = 1 ;
}
//mark point
if( flag < 3 ) ((uchar*)image->imageData)[image->widthStep * cur.y + cur.x] = 255;
//add it to another seq
CV_WRITE_SEQ_ELEM( cur, writer );
}
else
{
//exclude this point from contour
if( writing )
{
CvSeq* newseq = cvEndWriteSeq( &writer );
writing = 0;
if( tail )
{
tail->v_next = newseq;
newseq->v_prev = tail;
tail = newseq;
}
else
{
output = tail = newseq;
}
}
}
}
if( writing ) //if were not self intersections
{
CvSeq* newseq = cvEndWriteSeq( &writer );
writing = 0;
if( tail )
{
tail->v_next = newseq;
newseq->v_prev = tail;
tail = newseq;
}
else
{
output = tail = newseq;
}
}
return output;
}
/*void icvCutContour( CvSeq* current, IplImage* image )
{
//approx contour by single edges
CvSeqReader reader;
CvSeqReader rev_reader;
cvStartReadSeq( current, &reader, 0 );
int64* cur_pt = (int64*)reader.ptr;
int64* prev_pt = (int64*)reader.prev_elem;
//search for point a in aba position
for( int i = 0; i < current->total; i++ )
{
CV_NEXT_SEQ_ELEM( sizeof(int64), reader );
//compare current reader pos element with old previous
if( prev_pt[0] == ((int64*)reader.ptr)[0] )
{
//return to prev pos
CV_PREV_SEQ_ELEM( sizeof(int64), reader );
//this point is end of edge
//start going both directions and collect edge
cvStartReadSeq( current, &rev_reader, 1 );
int pos = cvGetSeqReaderPos( &reader );
cvSetSeqReaderPos( &rev_reader, pos );
//walk in both directions
while(1);
}
int64* cur_pt = (int64*)reader.ptr;
int64* prev_pt = (int64*)reader.prev_elem;
}
}
*/
#endif /* WIN32 */