Last active
December 19, 2015 16:59
-
-
Save ayoungprogrammer/5988112 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
static void | |
icvHoughLinesStandard( const CvMat* img, float rho, float theta, | |
int threshold, CvSeq *lines, int linesMax, float angStart, float angEnd ) | |
{ | |
cv::AutoBuffer<int> _accum, _sort_buf; | |
cv::AutoBuffer<float> _tabSin, _tabCos; | |
const uchar* image; | |
int step, width, height; | |
int numangle, numrho; | |
int total = 0; | |
int i, j; | |
float irho = 1 / rho; | |
double scale; | |
CV_Assert( CV_IS_MAT(img) && CV_MAT_TYPE(img->type) == CV_8UC1 ); | |
image = img->data.ptr; | |
step = img->step; | |
width = img->cols; | |
height = img->rows; | |
numangle = cvRound((angEnd-angStart) / theta); | |
numrho = cvRound(((width + height) * 2 + 1) / rho); | |
_accum.allocate((numangle+2) * (numrho+2)); | |
_sort_buf.allocate(numangle * numrho); | |
_tabSin.allocate(numangle); | |
_tabCos.allocate(numangle); | |
int *accum = _accum, *sort_buf = _sort_buf; | |
float *tabSin = _tabSin, *tabCos = _tabCos; | |
memset( accum, 0, sizeof(accum[0]) * (numangle+2) * (numrho+2) ); | |
float ang = angStart; | |
for(int n = 0; n < numangle; ang += theta, n++ ) | |
{ | |
tabSin[n] = (float)(sin((double)ang) * irho); | |
tabCos[n] = (float)(cos((double)ang) * irho); | |
} | |
// stage 1. fill accumulator | |
for( i = 0; i < height; i++ ) | |
for( j = 0; j < width; j++ ) | |
{ | |
if( image[i * step + j] != 0 ) | |
for(int n = 0; n < numangle; n++ ) | |
{ | |
int r = cvRound( j * tabCos[n] + i * tabSin[n] ); | |
r += (numrho - 1) / 2; | |
accum[(n+1) * (numrho+2) + r+1]++; | |
} | |
} | |
// stage 2. find local maximums | |
for(int r = 0; r < numrho; r++ ) | |
for(int n = 0; n < numangle; n++ ) | |
{ | |
int base = (n+1) * (numrho+2) + r+1; | |
if( accum[base] > threshold && | |
accum[base] > accum[base - 1] && accum[base] >= accum[base + 1] && | |
accum[base] > accum[base - numrho - 2] && accum[base] >= accum[base + numrho + 2] ) | |
sort_buf[total++] = base; | |
} | |
// stage 3. sort the detected lines by accumulator value | |
icvHoughSortDescent32s( sort_buf, total, accum ); | |
// stage 4. store the first min(total,linesMax) lines to the output buffer | |
linesMax = MIN(linesMax, total); | |
scale = 1./(numrho+2); | |
for( i = 0; i < linesMax; i++ ) | |
{ | |
CvLinePolar line; | |
int idx = sort_buf[i]; | |
int n = cvFloor(idx*scale) - 1; | |
int r = idx - (n+1)*(numrho+2) - 1; | |
line.rho = (r - (numrho - 1)*0.5f) * rho; | |
line.angle = n * theta +angStart; | |
cvSeqPush( lines, &line ); | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment