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Updated Documentation (HoughCircles)

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Rewrite the note on HoughCircles documentation to make it more clear

Add note to clarify that the output vector of found circles is sorted by
descending order of centres accumulator values.

Also delete reductant lines on the HoughCircles documentation.

Added comments to hough circles function.

Added comments to icvhoughgradient

Misalignment in line 1183 corrected
This commit is contained in:
HelenWong
2014-11-24 13:08:04 -08:00
parent 22ff1e8826
commit e88bf2bc30
2 changed files with 13 additions and 5 deletions
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12
modules/imgproc/src/hough.cpp
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@@ -1,4 +1,4 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
@@ -1024,10 +1024,14 @@ icvHoughCirclesGradient( CvMat* img, float dp, float min_dist,
CvSeqReader reader;
edges.reset(cvCreateMat( img->rows, img->cols, CV_8UC1 ));
// Use the Canny Edge Detector to detect all the edges in the image.
cvCanny( img, edges, MAX(canny_threshold/2,1), canny_threshold, 3 );
dx.reset(cvCreateMat( img->rows, img->cols, CV_16SC1 ));
dy.reset(cvCreateMat( img->rows, img->cols, CV_16SC1 ));
/*Use the Sobel Derivative to compute the local gradient of all the non-zero pixels in the edge image.*/
cvSobel( img, dx, 1, 0, 3 );
cvSobel( img, dy, 0, 1, 3 );
@@ -1038,6 +1042,8 @@ icvHoughCirclesGradient( CvMat* img, float dp, float min_dist,
cvZero(accum);
storage.reset(cvCreateMemStorage());
/* Create sequences for the nonzero pixels in the edge image and the centers of circles
which could be detected.*/
nz = cvCreateSeq( CV_32SC2, sizeof(CvSeq), sizeof(CvPoint), storage );
centers = cvCreateSeq( CV_32SC1, sizeof(CvSeq), sizeof(int), storage );
@@ -1118,7 +1124,8 @@ icvHoughCirclesGradient( CvMat* img, float dp, float min_dist,
sort_buf.resize( MAX(center_count,nz_count) );
cvCvtSeqToArray( centers, &sort_buf[0] );
/*Sort candidate centers in descending order of their accumulator values, so that the centers
with the most supporting pixels appear first.*/
std::sort(sort_buf.begin(), sort_buf.begin() + center_count, cv::hough_cmp_gt(adata));
cvClearSeq( centers );
cvSeqPushMulti( centers, &sort_buf[0], center_count );
@@ -1173,6 +1180,7 @@ icvHoughCirclesGradient( CvMat* img, float dp, float min_dist,
continue;
dist_buf->cols = nz_count1;
cvPow( dist_buf, dist_buf, 0.5 );
// Sort non-zero pixels according to their distance from the center.
std::sort(sort_buf.begin(), sort_buf.begin() + nz_count1, cv::hough_cmp_gt((int*)ddata));
dist_sum = start_dist = ddata[sort_buf[nz_count1-1]];