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imgproc: Canny with custom gradient

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This commit is contained in:
Alexander Alekhin 2016-07-11 16:08:09 +03:00
parent a2921fdede
commit 460b1dc2fa
2 changed files with 87 additions and 22 deletions
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13
modules/imgproc/include/opencv2/imgproc.hpp
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@ -1664,6 +1664,19 @@ CV_EXPORTS_W void Canny( InputArray image, OutputArray edges,
double threshold1, double threshold2,
int apertureSize = 3, bool L2gradient = false );
/** \overload
Finds edges in an image using the Canny algorithm with custom image gradient.
@param dx 16-bit x derivative of input image (CV_16SC1 or CV_16SC3).
@param dy 16-bit y derivative of input image (same type as dx).
@param edges,threshold1,threshold2,L2gradient See cv::Canny
*/
CV_EXPORTS_W void Canny( InputArray dx, InputArray dy,
OutputArray edges,
double threshold1, double threshold2,
bool L2gradient = false );
/** @brief Calculates the minimal eigenvalue of gradient matrices for corner detection.
The function is similar to cornerEigenValsAndVecs but it calculates and stores only the minimal

96
modules/imgproc/src/canny.cpp
View File

@ -43,6 +43,10 @@
#include "precomp.hpp"
#include "opencl_kernels_imgproc.hpp"
#ifdef _MSC_VER
#pragma warning( disable: 4127 ) // conditional expression is constant
#endif
#if defined (HAVE_IPP) && (IPP_VERSION_X100 >= 700)
#define USE_IPP_CANNY 1
@ -53,6 +57,10 @@
namespace cv
{
static void CannyImpl(Mat& dx_, Mat& dy_, Mat& _dst, double low_thresh, double high_thresh, bool L2gradient);
#ifdef HAVE_IPP
static bool ippCanny(const Mat& _src, Mat& _dst, float low, float high)
{
@ -585,9 +593,7 @@ private:
#endif
} // namespace cv
void cv::Canny( InputArray _src, OutputArray _dst,
void Canny( InputArray _src, OutputArray _dst,
double low_thresh, double high_thresh,
int aperture_size, bool L2gradient )
{
@ -683,14 +689,60 @@ while (borderPeaks.try_pop(m))
if (!m[mapstep+1]) CANNY_PUSH_SERIAL(m + mapstep + 1);
}
#else
// the final pass, form the final image
const uchar* pmap = map + mapstep + 1;
uchar* pdst = dst.ptr();
for (int i = 0; i < src.rows; i++, pmap += mapstep, pdst += dst.step)
{
for (int j = 0; j < src.cols; j++)
pdst[j] = (uchar)-(pmap[j] >> 1);
}
#else
Mat dx(src.rows, src.cols, CV_16SC(cn));
Mat dy(src.rows, src.cols, CV_16SC(cn));
Sobel(src, dx, CV_16S, 1, 0, aperture_size, 1, 0, BORDER_REPLICATE);
Sobel(src, dy, CV_16S, 0, 1, aperture_size, 1, 0, BORDER_REPLICATE);
CannyImpl(dx, dy, dst, low_thresh, high_thresh, L2gradient);
#endif
}
void Canny( InputArray _dx, InputArray _dy, OutputArray _dst,
double low_thresh, double high_thresh,
bool L2gradient )
{
CV_Assert(_dx.dims() == 2);
CV_Assert(_dx.type() == CV_16SC1 || _dx.type() == CV_16SC3);
CV_Assert(_dy.type() == _dx.type());
CV_Assert(_dx.sameSize(_dy));
if (low_thresh > high_thresh)
std::swap(low_thresh, high_thresh);
const int cn = _dx.channels();
const Size size = _dx.size();
_dst.create(size, CV_8U);
Mat dst = _dst.getMat();
Mat dx = _dx.getMat();
Mat dy = _dy.getMat();
if (cn > 1)
{
dx = dx.clone();
dy = dy.clone();
}
CannyImpl(dx, dy, dst, low_thresh, high_thresh, L2gradient);
}
static void CannyImpl(Mat& dx, Mat& dy, Mat& dst,
double low_thresh, double high_thresh, bool L2gradient)
{
const int cn = dx.channels();
const int cols = dx.cols, rows = dx.rows;
if (L2gradient)
{
low_thresh = std::min(32767.0, low_thresh);
@ -702,8 +754,8 @@ while (borderPeaks.try_pop(m))
int low = cvFloor(low_thresh);
int high = cvFloor(high_thresh);
ptrdiff_t mapstep = src.cols + 2;
AutoBuffer<uchar> buffer((src.cols+2)*(src.rows+2) + cn * mapstep * 3 * sizeof(int));
ptrdiff_t mapstep = cols + 2;
AutoBuffer<uchar> buffer((cols+2)*(rows+2) + cn * mapstep * 3 * sizeof(int));
int* mag_buf[3];
mag_buf[0] = (int*)(uchar*)buffer;
@ -713,9 +765,9 @@ while (borderPeaks.try_pop(m))
uchar* map = (uchar*)(mag_buf[2] + mapstep*cn);
memset(map, 1, mapstep);
memset(map + mapstep*(src.rows + 1), 1, mapstep);
memset(map + mapstep*(rows + 1), 1, mapstep);
int maxsize = std::max(1 << 10, src.cols * src.rows / 10);
int maxsize = std::max(1 << 10, cols * rows / 10);
std::vector<uchar*> stack(maxsize);
uchar **stack_top = &stack[0];
uchar **stack_bottom = &stack[0];
@ -744,17 +796,17 @@ while (borderPeaks.try_pop(m))
// 0 - the pixel might belong to an edge
// 1 - the pixel can not belong to an edge
// 2 - the pixel does belong to an edge
for (int i = 0; i <= src.rows; i++)
for (int i = 0; i <= rows; i++)
{
int* _norm = mag_buf[(i > 0) + 1] + 1;
if (i < src.rows)
if (i < rows)
{
short* _dx = dx.ptr<short>(i);
short* _dy = dy.ptr<short>(i);
if (!L2gradient)
{
int j = 0, width = src.cols * cn;
int j = 0, width = cols * cn;
#if CV_SSE2
if (haveSSE2)
{
@ -788,7 +840,7 @@ while (borderPeaks.try_pop(m))
}
else
{
int j = 0, width = src.cols * cn;
int j = 0, width = cols * cn;
#if CV_SSE2
if (haveSSE2)
{
@ -824,7 +876,7 @@ while (borderPeaks.try_pop(m))
if (cn > 1)
{
for(int j = 0, jn = 0; j < src.cols; ++j, jn += cn)
for(int j = 0, jn = 0; j < cols; ++j, jn += cn)
{
int maxIdx = jn;
for(int k = 1; k < cn; ++k)
@ -834,7 +886,7 @@ while (borderPeaks.try_pop(m))
_dy[j] = _dy[maxIdx];
}
}
_norm[-1] = _norm[src.cols] = 0;
_norm[-1] = _norm[cols] = 0;
}
else
memset(_norm-1, 0, /* cn* */mapstep*sizeof(int));
@ -845,7 +897,7 @@ while (borderPeaks.try_pop(m))
continue;
uchar* _map = map + mapstep*i + 1;
_map[-1] = _map[src.cols] = 1;
_map[-1] = _map[cols] = 1;
int* _mag = mag_buf[1] + 1; // take the central row
ptrdiff_t magstep1 = mag_buf[2] - mag_buf[1];
@ -854,17 +906,17 @@ while (borderPeaks.try_pop(m))
const short* _x = dx.ptr<short>(i-1);
const short* _y = dy.ptr<short>(i-1);
if ((stack_top - stack_bottom) + src.cols > maxsize)
if ((stack_top - stack_bottom) + cols > maxsize)
{
int sz = (int)(stack_top - stack_bottom);
maxsize = std::max(maxsize * 3/2, sz + src.cols);
maxsize = std::max(maxsize * 3/2, sz + cols);
stack.resize(maxsize);
stack_bottom = &stack[0];
stack_top = stack_bottom + sz;
}
int prev_flag = 0;
for (int j = 0; j < src.cols; j++)
for (int j = 0; j < cols; j++)
{
#define CANNY_SHIFT 15
const int TG22 = (int)(0.4142135623730950488016887242097*(1<<CANNY_SHIFT) + 0.5);
@ -943,18 +995,18 @@ __ocv_canny_push:
if (!m[mapstep+1]) CANNY_PUSH(m + mapstep + 1);
}
#endif
// the final pass, form the final image
const uchar* pmap = map + mapstep + 1;
uchar* pdst = dst.ptr();
for (int i = 0; i < src.rows; i++, pmap += mapstep, pdst += dst.step)
for (int i = 0; i < rows; i++, pmap += mapstep, pdst += dst.step)
{
for (int j = 0; j < src.cols; j++)
for (int j = 0; j < cols; j++)
pdst[j] = (uchar)-(pmap[j] >> 1);
}
}
} // namespace cv
void cvCanny( const CvArr* image, CvArr* edges, double threshold1,
double threshold2, int aperture_size )
{