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Merge pull request #3117 from KruchDmitriy:canny_opt

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pull/3163/head
Vadim Pisarevsky 10 years ago
parent 4d9d7e6ded 6ed168d3af
commit d66815978a
2 changed files with 390 additions and 502 deletions
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  1. 181
      modules/imgproc/src/canny.cpp
  2. 687
      modules/imgproc/src/opencl/canny.cl

181
modules/imgproc/src/canny.cpp
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@ -97,7 +97,23 @@ static bool ippCanny(const Mat& _src, Mat& _dst, float low, float high)
static bool ocl_Canny(InputArray _src, OutputArray _dst, float low_thresh, float high_thresh,
int aperture_size, bool L2gradient, int cn, const Size & size)
{
UMat dx(size, CV_16SC(cn)), dy(size, CV_16SC(cn));
UMat map;
const ocl::Device &dev = ocl::Device::getDefault();
int max_wg_size = (int)dev.maxWorkGroupSize();
int lSizeX = 32;
int lSizeY = max_wg_size / 32;
if (lSizeY == 0)
{
lSizeX = 16;
lSizeY = max_wg_size / 16;
}
if (lSizeY == 0)
{
lSizeY = 1;
}
if (L2gradient)
{
@ -110,144 +126,103 @@ static bool ocl_Canny(InputArray _src, OutputArray _dst, float low_thresh, float
high_thresh *= high_thresh;
}
int low = cvFloor(low_thresh), high = cvFloor(high_thresh);
Size esize(size.width + 2, size.height + 2);
UMat mag;
size_t globalsize[2] = { size.width, size.height }, localsize[2] = { 16, 16 };
if (aperture_size == 3 && !_src.isSubmatrix())
{
// Sobel calculation
char cvt[2][40];
ocl::Kernel calcSobelRowPassKernel("calcSobelRowPass", ocl::imgproc::canny_oclsrc,
format("-D OP_SOBEL -D cn=%d -D shortT=%s -D ucharT=%s"
" -D convertToIntT=%s -D intT=%s -D convertToShortT=%s", cn,
ocl::typeToStr(CV_16SC(cn)),
ocl::typeToStr(CV_8UC(cn)),
ocl::convertTypeStr(CV_8U, CV_32S, cn, cvt[0]),
ocl::typeToStr(CV_32SC(cn)),
ocl::convertTypeStr(CV_32S, CV_16S, cn, cvt[1])));
if (calcSobelRowPassKernel.empty())
return false;
UMat src = _src.getUMat(), dxBuf(size, CV_16SC(cn)), dyBuf(size, CV_16SC(cn));
calcSobelRowPassKernel.args(ocl::KernelArg::ReadOnly(src),
ocl::KernelArg::WriteOnlyNoSize(dxBuf),
ocl::KernelArg::WriteOnlyNoSize(dyBuf));
if (!calcSobelRowPassKernel.run(2, globalsize, localsize, false))
return false;
// magnitude calculation
ocl::Kernel magnitudeKernel("calcMagnitude_buf", ocl::imgproc::canny_oclsrc,
format("-D cn=%d%s -D OP_MAG_BUF -D shortT=%s -D convertToIntT=%s -D intT=%s",
cn, L2gradient ? " -D L2GRAD" : "",
ocl::typeToStr(CV_16SC(cn)),
ocl::convertTypeStr(CV_16S, CV_32S, cn, cvt[0]),
ocl::typeToStr(CV_32SC(cn))));
if (magnitudeKernel.empty())
/*
stage1_with_sobel:
Sobel operator
Calc magnitudes
Non maxima suppression
Double thresholding
*/
char cvt[40];
ocl::Kernel with_sobel("stage1_with_sobel", ocl::imgproc::canny_oclsrc,
format("-D WITH_SOBEL -D cn=%d -D TYPE=%s -D convert_intN=%s -D intN=%s -D GRP_SIZEX=%d -D GRP_SIZEY=%d%s",
cn, ocl::memopTypeToStr(_src.depth()),
ocl::convertTypeStr(_src.type(), CV_32SC(cn), cn, cvt),
ocl::memopTypeToStr(CV_32SC(cn)),
lSizeX, lSizeY,
L2gradient ? " -D L2GRAD" : ""));
if (with_sobel.empty())
return false;
mag = UMat(esize, CV_32SC1, Scalar::all(0));
dx.create(size, CV_16SC(cn));
dy.create(size, CV_16SC(cn));
UMat src = _src.getUMat();
map.create(size, CV_32S);
with_sobel.args(ocl::KernelArg::ReadOnly(src),
ocl::KernelArg::WriteOnlyNoSize(map),
low, high);
magnitudeKernel.args(ocl::KernelArg::ReadOnlyNoSize(dxBuf), ocl::KernelArg::ReadOnlyNoSize(dyBuf),
ocl::KernelArg::WriteOnlyNoSize(dx), ocl::KernelArg::WriteOnlyNoSize(dy),
ocl::KernelArg::WriteOnlyNoSize(mag), size.height, size.width);
size_t globalsize[2] = { size.width, size.height },
localsize[2] = { lSizeX, lSizeY };
if (!magnitudeKernel.run(2, globalsize, localsize, false))
if (!with_sobel.run(2, globalsize, localsize, false))
return false;
}
else
{
/*
stage1_without_sobel:
Calc magnitudes
Non maxima suppression
Double thresholding
*/
UMat dx, dy;
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);
// magnitude calculation
ocl::Kernel magnitudeKernel("calcMagnitude", ocl::imgproc::canny_oclsrc,
format("-D OP_MAG -D cn=%d%s -D intT=int -D shortT=short -D convertToIntT=convert_int_sat",
cn, L2gradient ? " -D L2GRAD" : ""));
if (magnitudeKernel.empty())
return false;
mag = UMat(esize, CV_32SC1, Scalar::all(0));
magnitudeKernel.args(ocl::KernelArg::ReadOnlyNoSize(dx), ocl::KernelArg::ReadOnlyNoSize(dy),
ocl::KernelArg::WriteOnlyNoSize(mag), size.height, size.width);
if (!magnitudeKernel.run(2, globalsize, NULL, false))
return false;
}
// map calculation
ocl::Kernel calcMapKernel("calcMap", ocl::imgproc::canny_oclsrc,
format("-D OP_MAP -D cn=%d", cn));
if (calcMapKernel.empty())
ocl::Kernel without_sobel("stage1_without_sobel", ocl::imgproc::canny_oclsrc,
format("-D WITHOUT_SOBEL -D cn=%d -D GRP_SIZEX=%d -D GRP_SIZEY=%d%s",
cn, lSizeX, lSizeY, L2gradient ? " -D L2GRAD" : ""));
if (without_sobel.empty())
return false;
UMat map(esize, CV_32SC1);
calcMapKernel.args(ocl::KernelArg::ReadOnlyNoSize(dx), ocl::KernelArg::ReadOnlyNoSize(dy),
ocl::KernelArg::ReadOnlyNoSize(mag), ocl::KernelArg::WriteOnlyNoSize(map),
size.height, size.width, low, high);
map.create(size, CV_32S);
without_sobel.args(ocl::KernelArg::ReadOnlyNoSize(dx), ocl::KernelArg::ReadOnlyNoSize(dy),
ocl::KernelArg::WriteOnly(map),
low, high);
if (!calcMapKernel.run(2, globalsize, localsize, false))
return false;
size_t globalsize[2] = { size.width, size.height },
localsize[2] = { lSizeX, lSizeY };
// local hysteresis thresholding
ocl::Kernel edgesHysteresisLocalKernel("edgesHysteresisLocal", ocl::imgproc::canny_oclsrc,
"-D OP_HYST_LOCAL");
if (edgesHysteresisLocalKernel.empty())
if (!without_sobel.run(2, globalsize, localsize, false))
return false;
}
UMat stack(1, size.area(), CV_16UC2), counter(1, 1, CV_32SC1, Scalar::all(0));
edgesHysteresisLocalKernel.args(ocl::KernelArg::ReadOnlyNoSize(map), ocl::KernelArg::PtrReadWrite(stack),
ocl::KernelArg::PtrReadWrite(counter), size.height, size.width);
if (!edgesHysteresisLocalKernel.run(2, globalsize, localsize, false))
return false;
int PIX_PER_WI = 8;
/*
stage2:
hysteresis (add weak edges if they are connected with strong edges)
*/
// global hysteresis thresholding
UMat stack2(1, size.area(), CV_16UC2);
int count;
ocl::Kernel edgesHysteresis("stage2_hysteresis", ocl::imgproc::canny_oclsrc,
format("-D STAGE2 -D PIX_PER_WI=%d", PIX_PER_WI));
for ( ; ; )
{
ocl::Kernel edgesHysteresisGlobalKernel("edgesHysteresisGlobal", ocl::imgproc::canny_oclsrc,
"-D OP_HYST_GLOBAL");
if (edgesHysteresisGlobalKernel.empty())
if (edgesHysteresis.empty())
return false;
{
Mat _counter = counter.getMat(ACCESS_RW);
count = _counter.at<int>(0, 0);
if (count == 0)
break;
_counter.at<int>(0, 0) = 0;
}
edgesHysteresis.args(ocl::KernelArg::ReadWrite(map));
edgesHysteresisGlobalKernel.args(ocl::KernelArg::ReadOnlyNoSize(map), ocl::KernelArg::PtrReadWrite(stack),
ocl::KernelArg::PtrReadWrite(stack2), ocl::KernelArg::PtrReadWrite(counter),
size.height, size.width, count);
int sizey = lSizeY / PIX_PER_WI;
if (sizey == 0)
sizey = 1;
#define divUp(total, grain) ((total + grain - 1) / grain)
size_t localsize2[2] = { 128, 1 }, globalsize2[2] = { std::min(count, 65535) * 128, divUp(count, 65535) };
#undef divUp
size_t globalsize[2] = { size.width, size.height / PIX_PER_WI }, localsize[2] = { lSizeX, sizey };
if (!edgesHysteresisGlobalKernel.run(2, globalsize2, localsize2, false))
if (!edgesHysteresis.run(2, globalsize, localsize, false))
return false;
std::swap(stack, stack2);
}
// get edges
ocl::Kernel getEdgesKernel("getEdges", ocl::imgproc::canny_oclsrc, "-D OP_EDGES");
ocl::Kernel getEdgesKernel("getEdges", ocl::imgproc::canny_oclsrc,
format("-D GET_EDGES -D PIX_PER_WI=%d", PIX_PER_WI));
if (getEdgesKernel.empty())
return false;
_dst.create(size, CV_8UC1);
UMat dst = _dst.getUMat();
getEdgesKernel.args(ocl::KernelArg::ReadOnlyNoSize(map), ocl::KernelArg::WriteOnly(dst));
getEdgesKernel.args(ocl::KernelArg::ReadOnly(map), ocl::KernelArg::WriteOnlyNoSize(dst));
return getEdgesKernel.run(2, globalsize, NULL, false);
}

687
modules/imgproc/src/opencl/canny.cl
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@ -43,518 +43,431 @@
//
//M*/
#ifdef OP_SOBEL
#define TG22 0.4142135623730950488016887242097f
#define TG67 2.4142135623730950488016887242097f
#if cn != 3
#define loadpix(addr) convertToIntT(*(__global const ucharT *)(addr))
#define storepix(val, addr) *(__global shortT *)(addr) = convertToShortT(val)
#define shortSize (int)sizeof(shortT)
#ifdef WITH_SOBEL
#if cn == 1
#define loadpix(addr) convert_intN(*(__global const TYPE *)(addr))
#else
#define loadpix(addr) convertToIntT(vload3(0, (__global const uchar *)(addr)))
#define storepix(val, addr) vstore3(convertToShortT(val), 0, (__global short *)(addr))
#define shortSize (int)sizeof(short) * cn
#define loadpix(addr) convert_intN(vload3(0, (__global const TYPE *)(addr)))
#endif
#define storepix(value, addr) *(__global int *)(addr) = (int)(value)
/*
stage1_with_sobel:
Sobel operator
Calc magnitudes
Non maxima suppression
Double thresholding
*/
__constant int prev[4][2] = {
{ 0, -1 },
{ -1, 1 },
{ -1, 0 },
{ -1, -1 }
};
// Smoothing perpendicular to the derivative direction with a triangle filter
// only support 3x3 Sobel kernel
// h (-1) = 1, h (0) = 2, h (1) = 1
// h'(-1) = -1, h'(0) = 0, h'(1) = 1
// thus sobel 2D operator can be calculated as:
// h'(x, y) = h'(x)h(y) for x direction
//
// src input 8bit single channel image data
// dx_buf output dx buffer
// dy_buf output dy buffer
__constant int next[4][2] = {
{ 0, 1 },
{ 1, -1 },
{ 1, 0 },
{ 1, 1 }
};
__kernel void calcSobelRowPass(__global const uchar * src, int src_step, int src_offset, int rows, int cols,
__global uchar * dx_buf, int dx_buf_step, int dx_buf_offset,
__global uchar * dy_buf, int dy_buf_step, int dy_buf_offset)
inline int3 sobel(int idx, __local const intN *smem)
{
int gidx = get_global_id(0);
int gidy = get_global_id(1);
// result: x, y, mag
int3 res;
int lidx = get_local_id(0);
int lidy = get_local_id(1);
intN dx = smem[idx + 2] - smem[idx]
+ 2 * (smem[idx + GRP_SIZEX + 6] - smem[idx + GRP_SIZEX + 4])
+ smem[idx + 2 * GRP_SIZEX + 10] - smem[idx + 2 * GRP_SIZEX + 8];
__local intT smem[16][18];
intN dy = smem[idx] - smem[idx + 2 * GRP_SIZEX + 8]
+ 2 * (smem[idx + 1] - smem[idx + 2 * GRP_SIZEX + 9])
+ smem[idx + 2] - smem[idx + 2 * GRP_SIZEX + 10];
smem[lidy][lidx + 1] = loadpix(src + mad24(src_step, min(gidy, rows - 1), mad24(gidx, cn, src_offset)));
if (lidx == 0)
#ifdef L2GRAD
intN magN = dx * dx + dy * dy;
#else
intN magN = convert_intN(abs(dx) + abs(dy));
#endif
#if cn == 1
res.z = magN;
res.x = dx;
res.y = dy;
#else
res.z = max(magN.x, max(magN.y, magN.z));
if (res.z == magN.y)
{
smem[lidy][0] = loadpix(src + mad24(src_step, min(gidy, rows - 1), mad24(max(gidx - 1, 0), cn, src_offset)));
smem[lidy][17] = loadpix(src + mad24(src_step, min(gidy, rows - 1), mad24(min(gidx + 16, cols - 1), cn, src_offset)));
dx.x = dx.y;
dy.x = dy.y;
}
barrier(CLK_LOCAL_MEM_FENCE);
if (gidy < rows && gidx < cols)
else if (res.z == magN.z)
{
storepix(smem[lidy][lidx + 2] - smem[lidy][lidx],
dx_buf + mad24(gidy, dx_buf_step, mad24(gidx, shortSize, dx_buf_offset)));
storepix(mad24(2, smem[lidy][lidx + 1], smem[lidy][lidx] + smem[lidy][lidx + 2]),
dy_buf + mad24(gidy, dy_buf_step, mad24(gidx, shortSize, dy_buf_offset)));
dx.x = dx.z;
dy.x = dy.z;
}
}
#elif defined OP_MAG_BUF || defined OP_MAG
inline intT calc(shortT x, shortT y)
{
#ifdef L2GRAD
intT intx = convertToIntT(x), inty = convertToIntT(y);
return intx * intx + inty * inty;
#else
return convertToIntT( (x >= (shortT)(0) ? x : -x) + (y >= (shortT)(0) ? y : -y) );
res.x = dx.x;
res.y = dy.x;
#endif
}
#ifdef OP_MAG
return res;
}
// calculate the magnitude of the filter pass combining both x and y directions
// This is the non-buffered version(non-3x3 sobel)
//
// dx_buf dx buffer, calculated from calcSobelRowPass
// dy_buf dy buffer, calculated from calcSobelRowPass
// dx direvitive in x direction output
// dy direvitive in y direction output
// mag magnitude direvitive of xy output
__kernel void calcMagnitude(__global const uchar * dxptr, int dx_step, int dx_offset,
__global const uchar * dyptr, int dy_step, int dy_offset,
__global uchar * magptr, int mag_step, int mag_offset, int rows, int cols)
__kernel void stage1_with_sobel(__global const uchar *src, int src_step, int src_offset, int rows, int cols,
__global uchar *map, int map_step, int map_offset,
int low_thr, int high_thr)
{
int x = get_global_id(0);
int y = get_global_id(1);
__local intN smem[(GRP_SIZEX + 4) * (GRP_SIZEY + 4)];
if (y < rows && x < cols)
{
int dx_index = mad24(dx_step, y, mad24(x, (int)sizeof(short) * cn, dx_offset));
int dy_index = mad24(dy_step, y, mad24(x, (int)sizeof(short) * cn, dy_offset));
int mag_index = mad24(mag_step, y + 1, mad24(x + 1, (int)sizeof(int), mag_offset));
__global short * dx = (__global short *)(dxptr + dx_index);
__global short * dy = (__global short *)(dyptr + dy_index);
__global int * mag = (__global int *)(magptr + mag_index);
int lidx = get_local_id(0);
int lidy = get_local_id(1);
int cmag = calc(dx[0], dy[0]);
#if cn > 1
short cx = dx[0], cy = dy[0];
int pmag;
int start_x = GRP_SIZEX * get_group_id(0);
int start_y = GRP_SIZEY * get_group_id(1);
#pragma unroll
for (int i = 1; i < cn; ++i)
int i = lidx + lidy * GRP_SIZEX;
for (int j = i; j < (GRP_SIZEX + 4) * (GRP_SIZEY + 4); j += GRP_SIZEX * GRP_SIZEY)
{
pmag = calc(dx[i], dy[i]);
if (pmag > cmag)
cmag = pmag, cx = dx[i], cy = dy[i];
int x = clamp(start_x - 2 + (j % (GRP_SIZEX + 4)), 0, cols - 1);
int y = clamp(start_y - 2 + (j / (GRP_SIZEX + 4)), 0, rows - 1);
smem[j] = loadpix(src + mad24(y, src_step, mad24(x, cn * (int)sizeof(TYPE), src_offset)));
}
dx[0] = cx, dy[0] = cy;
#endif
mag[0] = cmag;
}
}
barrier(CLK_LOCAL_MEM_FENCE);
#elif defined OP_MAG_BUF
//// Sobel, Magnitude
//
#if cn != 3
#define loadpix(addr) *(__global const shortT *)(addr)
#define shortSize (int)sizeof(shortT)
#else
#define loadpix(addr) vload3(0, (__global const short *)(addr))
#define shortSize (int)sizeof(short)*cn
#endif
__local int mag[(GRP_SIZEX + 2) * (GRP_SIZEY + 2)];
// calculate the magnitude of the filter pass combining both x and y directions
// This is the buffered version(3x3 sobel)
//
// dx_buf dx buffer, calculated from calcSobelRowPass
// dy_buf dy buffer, calculated from calcSobelRowPass
// dx direvitive in x direction output
// dy direvitive in y direction output
// mag magnitude direvitive of xy output
__kernel void calcMagnitude_buf(__global const uchar * dx_buf, int dx_buf_step, int dx_buf_offset,
__global const uchar * dy_buf, int dy_buf_step, int dy_buf_offset,
__global uchar * dx, int dx_step, int dx_offset,
__global uchar * dy, int dy_step, int dy_offset,
__global uchar * mag, int mag_step, int mag_offset, int rows, int cols)
{
int gidx = get_global_id(0);
int gidy = get_global_id(1);
lidx++;
lidy++;
int lidx = get_local_id(0);
int lidy = get_local_id(1);
if (i < GRP_SIZEX + 2)
{
int grp_sizey = min(GRP_SIZEY + 1, rows - start_y);
mag[i] = (sobel(i, smem)).z;
mag[i + grp_sizey * (GRP_SIZEX + 2)] = (sobel(i + grp_sizey * (GRP_SIZEX + 4), smem)).z;
}
if (i < GRP_SIZEY + 2)
{
int grp_sizex = min(GRP_SIZEX + 1, cols - start_x);
mag[i * (GRP_SIZEX + 2)] = (sobel(i * (GRP_SIZEX + 4), smem)).z;
mag[i * (GRP_SIZEX + 2) + grp_sizex] = (sobel(i * (GRP_SIZEX + 4) + grp_sizex, smem)).z;
}
__local shortT sdx[18][16];
__local shortT sdy[18][16];
int idx = lidx + lidy * (GRP_SIZEX + 4);
i = lidx + lidy * (GRP_SIZEX + 2);
sdx[lidy + 1][lidx] = loadpix(dx_buf + mad24(min(gidy, rows - 1), dx_buf_step, mad24(gidx, shortSize, dx_buf_offset)));
sdy[lidy + 1][lidx] = loadpix(dy_buf + mad24(min(gidy, rows - 1), dy_buf_step, mad24(gidx, shortSize, dy_buf_offset)));
if (lidy == 0)
{
sdx[0][lidx] = loadpix(dx_buf + mad24(clamp(gidy - 1, 0, rows - 1), dx_buf_step, mad24(gidx, shortSize, dx_buf_offset)));
sdx[17][lidx] = loadpix(dx_buf + mad24(min(gidy + 16, rows - 1), dx_buf_step, mad24(gidx, shortSize, dx_buf_offset)));
int3 res = sobel(idx, smem);
mag[i] = res.z;
int x = res.x;
int y = res.y;
sdy[0][lidx] = loadpix(dy_buf + mad24(clamp(gidy - 1, 0, rows - 1), dy_buf_step, mad24(gidx, shortSize, dy_buf_offset)));
sdy[17][lidx] = loadpix(dy_buf + mad24(min(gidy + 16, rows - 1), dy_buf_step, mad24(gidx, shortSize, dy_buf_offset)));
}
barrier(CLK_LOCAL_MEM_FENCE);
if (gidx < cols && gidy < rows)
{
shortT x = sdx[lidy + 1][lidx] * (shortT)(2) + sdx[lidy][lidx] + sdx[lidy + 2][lidx];
shortT y = -sdy[lidy][lidx] + sdy[lidy + 2][lidx];
//// Threshold + Non maxima suppression
//
#if cn == 1
*(__global short *)(dx + mad24(gidy, dx_step, mad24(gidx, shortSize, dx_offset))) = x;
*(__global short *)(dy + mad24(gidy, dy_step, mad24(gidx, shortSize, dy_offset))) = y;
/*
Sector numbers
*(__global int *)(mag + mad24(gidy + 1, mag_step, mad24(gidx + 1, (int)sizeof(int), mag_offset))) = calc(x, y);
#elif cn == 3
intT magv = calc(x, y);
short cx = x.x, cy = y.x;
int cmag = magv.x;
3 2 1
* * *
* * *
0*******0
* * *
* * *
1 2 3
if (cmag < magv.y)
cx = x.y, cy = y.y, cmag = magv.y;
if (cmag < magv.z)
cx = x.z, cy = y.z, cmag = magv.z;
We need to determine arctg(dy / dx) to one of the four directions: 0, 45, 90 or 135 degrees.
Therefore if abs(dy / dx) belongs to the interval
[0, tg(22.5)] -> 0 direction
[tg(22.5), tg(67.5)] -> 1 or 3
[tg(67,5), +oo) -> 2
*(__global short *)(dx + mad24(gidy, dx_step, mad24(gidx, shortSize, dx_offset))) = cx;
*(__global short *)(dy + mad24(gidy, dy_step, mad24(gidx, shortSize, dy_offset))) = cy;
Since tg(67.5) = 1 / tg(22.5), if we take
a = abs(dy / dx) * tg(22.5) and b = abs(dy / dx) * tg(67.5)
we can get another intervals
*(__global int *)(mag + mad24(gidy + 1, mag_step, mad24(gidx + 1, (int)sizeof(int), mag_offset))) = cmag;
#endif
}
}
in case a:
[0, tg(22.5)^2] -> 0
[tg(22.5)^2, 1] -> 1, 3
[1, +oo) -> 2
#endif
in case b:
[0, 1] -> 0
[1, tg(67.5)^2] -> 1,3
[tg(67.5)^2, +oo) -> 2
#elif defined OP_MAP
//////////////////////////////////////////////////////////////////////////////////////////
// 0.4142135623730950488016887242097 is tan(22.5)
#define CANNY_SHIFT 15
#define TG22 (int)(0.4142135623730950488016887242097f*(1<<CANNY_SHIFT) + 0.5f)
// First pass of edge detection and non-maximum suppression
// edgetype is set to for each pixel:
// 0 - below low thres, not an edge
// 1 - maybe an edge
// 2 - is an edge, either magnitude is greater than high thres, or
// Given estimates of the image gradients, a search is then carried out
// to determine if the gradient magnitude assumes a local maximum in the gradient direction.
// if the rounded gradient angle is zero degrees (i.e. the edge is in the north-south direction) the point will be considered to be on the edge if its gradient magnitude is greater than the magnitudes in the west and east directions,
// if the rounded gradient angle is 90 degrees (i.e. the edge is in the east-west direction) the point will be considered to be on the edge if its gradient magnitude is greater than the magnitudes in the north and south directions,
// if the rounded gradient angle is 135 degrees (i.e. the edge is in the north east-south west direction) the point will be considered to be on the edge if its gradient magnitude is greater than the magnitudes in the north west and south east directions,
// if the rounded gradient angle is 45 degrees (i.e. the edge is in the north west-south east direction)the point will be considered to be on the edge if its gradient magnitude is greater than the magnitudes in the north east and south west directions.
//
// dx, dy direvitives of x and y direction
// mag magnitudes calculated from calcMagnitude function
// map output containing raw edge types
__kernel void calcMap(__global const uchar * dx, int dx_step, int dx_offset,
__global const uchar * dy, int dy_step, int dy_offset,
__global const uchar * mag, int mag_step, int mag_offset,
__global uchar * map, int map_step, int map_offset,
int rows, int cols, int low_thresh, int high_thresh)
{
__local int smem[18][18];
that can help to find direction without conditions.
0 - might belong to an edge
1 - pixel doesn't belong to an edge
2 - belong to an edge
*/
int gidx = get_global_id(0);
int gidy = get_global_id(1);
int lidx = get_local_id(0);
int lidy = get_local_id(1);
int grp_idx = get_global_id(0) & 0xFFFFF0;
int grp_idy = get_global_id(1) & 0xFFFFF0;
int tid = mad24(lidy, 16, lidx);
int lx = tid % 18;
int ly = tid / 18;
if (gidx >= cols || gidy >= rows)
return;
mag += mag_offset;
if (ly < 14)
smem[ly][lx] = *(__global const int *)(mag +
mad24(mag_step, min(grp_idy + ly, rows - 1), (int)sizeof(int) * (grp_idx + lx)));
if (ly < 4 && grp_idy + ly + 14 <= rows && grp_idx + lx <= cols)
smem[ly + 14][lx] = *(__global const int *)(mag +
mad24(mag_step, min(grp_idy + ly + 14, rows - 1), (int)sizeof(int) * (grp_idx + lx)));
barrier(CLK_LOCAL_MEM_FENCE);
int mag0 = mag[i];
if (gidy < rows && gidx < cols)
int value = 1;
if (mag0 > low_thr)
{
// 0 - the pixel can not belong to an edge
// 1 - the pixel might belong to an edge
// 2 - the pixel does belong to an edge
int edge_type = 0;
int m = smem[lidy + 1][lidx + 1];
int a = (y / (float)x) * TG22;
int b = (y / (float)x) * TG67;
if (m > low_thresh)
{
short xs = *(__global const short *)(dx + mad24(gidy, dx_step, mad24(gidx, (int)sizeof(short) * cn, dx_offset)));
short ys = *(__global const short *)(dy + mad24(gidy, dy_step, mad24(gidx, (int)sizeof(short) * cn, dy_offset)));
int x = abs(xs), y = abs(ys);
a = min((int)abs(a), 1) + 1;
b = min((int)abs(b), 1);
int tg22x = x * TG22;
y <<= CANNY_SHIFT;
// a = { 1, 2 }
// b = { 0, 1 }
// a * b = { 0, 1, 2 } - directions that we need ( + 3 if x ^ y < 0)
if (y < tg22x)
{
if (m > smem[lidy + 1][lidx] && m >= smem[lidy + 1][lidx + 2])
edge_type = 1 + (int)(m > high_thresh);
}
else
{
int tg67x = tg22x + (x << (1 + CANNY_SHIFT));
if (y > tg67x)
{
if (m > smem[lidy][lidx + 1]&& m >= smem[lidy + 2][lidx + 1])
edge_type = 1 + (int)(m > high_thresh);
}
else
int dir3 = (a * b) & (((x ^ y) & 0x80000000) >> 31); // if a = 1, b = 1, dy ^ dx < 0
int dir = a * b + 2 * dir3;
int prev_mag = mag[(lidy + prev[dir][0]) * (GRP_SIZEX + 2) + lidx + prev[dir][1]];
int next_mag = mag[(lidy + next[dir][0]) * (GRP_SIZEX + 2) + lidx + next[dir][1]] + (dir & 1);
if (mag0 > prev_mag && mag0 >= next_mag)
{
int s = (xs ^ ys) < 0 ? -1 : 1;
if (m > smem[lidy][lidx + 1 - s]&& m > smem[lidy + 2][lidx + 1 + s])
edge_type = 1 + (int)(m > high_thresh);
}
value = (mag0 > high_thr) ? 2 : 0;
}
}
*(__global int *)(map + mad24(map_step, gidy + 1, mad24(gidx + 1, (int)sizeof(int), + map_offset))) = edge_type;
}
storepix(value, map + mad24(gidy, map_step, mad24(gidx, (int)sizeof(int), map_offset)));
}
#undef CANNY_SHIFT
#undef TG22
#elif defined WITHOUT_SOBEL
#elif defined OP_HYST_LOCAL
/*
stage1_without_sobel:
Calc magnitudes
Non maxima suppression
Double thresholding
*/
struct PtrStepSz
{
__global uchar * ptr;
int step, rows, cols;
#define loadpix(addr) (__global short *)(addr)
#define storepix(val, addr) *(__global int *)(addr) = (int)(val)
#ifdef L2GRAD
#define dist(x, y) ((int)(x) * (x) + (int)(y) * (y))
#else
#define dist(x, y) (abs(x) + abs(y))
#endif
__constant int prev[4][2] = {
{ 0, -1 },
{ -1, -1 },
{ -1, 0 },
{ -1, 1 }
};
inline int get(struct PtrStepSz data, int y, int x)
{
return *(__global int *)(data.ptr + mad24(data.step, y + 1, (int)sizeof(int) * (x + 1)));
}
__constant int next[4][2] = {
{ 0, 1 },
{ 1, 1 },
{ 1, 0 },
{ 1, -1 }
};
inline void set(struct PtrStepSz data, int y, int x, int value)
__kernel void stage1_without_sobel(__global const uchar *dxptr, int dx_step, int dx_offset,
__global const uchar *dyptr, int dy_step, int dy_offset,
__global uchar *map, int map_step, int map_offset, int rows, int cols,
int low_thr, int high_thr)
{
*(__global int *)(data.ptr + mad24(data.step, y + 1, (int)sizeof(int) * (x + 1))) = value;
}
int start_x = get_group_id(0) * GRP_SIZEX;
int start_y = get_group_id(1) * GRP_SIZEY;
// perform Hysteresis for pixel whose edge type is 1
//
// If candidate pixel (edge type is 1) has a neighbour pixel (in 3x3 area) with type 2, it is believed to be part of an edge and
// marked as edge. Each thread will iterate for 16 times to connect local edges.
// Candidate pixel being identified as edge will then be tested if there is nearby potiential edge points. If there is, counter will
// be incremented by 1 and the point location is stored. These potiential candidates will be processed further in next kernel.
//
// map raw edge type results calculated from calcMap.
// stack the potiential edge points found in this kernel call
// counter the number of potiential edge points
int lidx = get_local_id(0);
int lidy = get_local_id(1);
__kernel void edgesHysteresisLocal(__global uchar * map_ptr, int map_step, int map_offset,
__global ushort2 * st, __global unsigned int * counter,
int rows, int cols)
{
struct PtrStepSz map = { map_ptr + map_offset, map_step, rows + 1, cols + 1 };
__local int smem[18][18];
int2 blockIdx = (int2)(get_group_id(0), get_group_id(1));
int2 blockDim = (int2)(get_local_size(0), get_local_size(1));
int2 threadIdx = (int2)(get_local_id(0), get_local_id(1));
const int x = blockIdx.x * blockDim.x + threadIdx.x;
const int y = blockIdx.y * blockDim.y + threadIdx.y;
smem[threadIdx.y + 1][threadIdx.x + 1] = x < map.cols && y < map.rows ? get(map, y, x) : 0;
if (threadIdx.y == 0)
smem[0][threadIdx.x + 1] = x < map.cols ? get(map, y - 1, x) : 0;
if (threadIdx.y == blockDim.y - 1)
smem[blockDim.y + 1][threadIdx.x + 1] = y + 1 < map.rows ? get(map, y + 1, x) : 0;
if (threadIdx.x == 0)
smem[threadIdx.y + 1][0] = y < map.rows ? get(map, y, x - 1) : 0;
if (threadIdx.x == blockDim.x - 1)
smem[threadIdx.y + 1][blockDim.x + 1] = x + 1 < map.cols && y < map.rows ? get(map, y, x + 1) : 0;
if (threadIdx.x == 0 && threadIdx.y == 0)
smem[0][0] = y > 0 && x > 0 ? get(map, y - 1, x - 1) : 0;
if (threadIdx.x == blockDim.x - 1 && threadIdx.y == 0)
smem[0][blockDim.x + 1] = y > 0 && x + 1 < map.cols ? get(map, y - 1, x + 1) : 0;
if (threadIdx.x == 0 && threadIdx.y == blockDim.y - 1)
smem[blockDim.y + 1][0] = y + 1 < map.rows && x > 0 ? get(map, y + 1, x - 1) : 0;
if (threadIdx.x == blockDim.x - 1 && threadIdx.y == blockDim.y - 1)
smem[blockDim.y + 1][blockDim.x + 1] = y + 1 < map.rows && x + 1 < map.cols ? get(map, y + 1, x + 1) : 0;
__local int mag[(GRP_SIZEX + 2) * (GRP_SIZEY + 2)];
__local short2 sigma[(GRP_SIZEX + 2) * (GRP_SIZEY + 2)];
barrier(CLK_LOCAL_MEM_FENCE);
#pragma unroll
for (int i = lidx + lidy * GRP_SIZEX; i < (GRP_SIZEX + 2) * (GRP_SIZEY + 2); i += GRP_SIZEX * GRP_SIZEY)
{
int x = clamp(start_x - 1 + i % (GRP_SIZEX + 2), 0, cols - 1);
int y = clamp(start_y - 1 + i / (GRP_SIZEX + 2), 0, rows - 1);
if (x >= cols || y >= rows)
return;
int dx_index = mad24(y, dx_step, mad24(x, cn * (int)sizeof(short), dx_offset));
int dy_index = mad24(y, dy_step, mad24(x, cn * (int)sizeof(short), dy_offset));
int n;
__global short *dx = loadpix(dxptr + dx_index);
__global short *dy = loadpix(dyptr + dy_index);
#pragma unroll
for (int k = 0; k < 16; ++k)
int mag0 = dist(dx[0], dy[0]);
#if cn > 1
short cdx = dx[0], cdy = dy[0];
#pragma unroll
for (int j = 1; j < cn; ++j)
{
n = 0;
if (smem[threadIdx.y + 1][threadIdx.x + 1] == 1)
int mag1 = dist(dx[j], dy[j]);
if (mag1 > mag0)
{
n += smem[threadIdx.y ][threadIdx.x ] == 2;
n += smem[threadIdx.y ][threadIdx.x + 1] == 2;
n += smem[threadIdx.y ][threadIdx.x + 2] == 2;
mag0 = mag1;
cdx = dx[j];
cdy = dy[j];
}
}
dx[0] = cdx;
dy[0] = cdy;
#endif
mag[i] = mag0;
sigma[i] = (short2)(dx[0], dy[0]);
}
n += smem[threadIdx.y + 1][threadIdx.x ] == 2;
n += smem[threadIdx.y + 1][threadIdx.x + 2] == 2;
barrier(CLK_LOCAL_MEM_FENCE);
n += smem[threadIdx.y + 2][threadIdx.x ] == 2;
n += smem[threadIdx.y + 2][threadIdx.x + 1] == 2;
n += smem[threadIdx.y + 2][threadIdx.x + 2] == 2;
}
int gidx = get_global_id(0);
int gidy = get_global_id(1);
if (n > 0)
smem[threadIdx.y + 1][threadIdx.x + 1] = 2;
}
if (gidx >= cols || gidy >= rows)
return;
lidx++;
lidy++;
const int e = smem[threadIdx.y + 1][threadIdx.x + 1];
set(map, y, x, e);
n = 0;
int mag0 = mag[lidx + lidy * (GRP_SIZEX + 2)];
short x = (sigma[lidx + lidy * (GRP_SIZEX + 2)]).x;
short y = (sigma[lidx + lidy * (GRP_SIZEX + 2)]).y;
if (e == 2)
int value = 1;
if (mag0 > low_thr)
{
n += smem[threadIdx.y ][threadIdx.x ] == 1;
n += smem[threadIdx.y ][threadIdx.x + 1] == 1;
n += smem[threadIdx.y ][threadIdx.x + 2] == 1;
int a = (y / (float)x) * TG22;
int b = (y / (float)x) * TG67;
n += smem[threadIdx.y + 1][threadIdx.x ] == 1;
n += smem[threadIdx.y + 1][threadIdx.x + 2] == 1;
a = min((int)abs(a), 1) + 1;
b = min((int)abs(b), 1);
n += smem[threadIdx.y + 2][threadIdx.x ] == 1;
n += smem[threadIdx.y + 2][threadIdx.x + 1] == 1;
n += smem[threadIdx.y + 2][threadIdx.x + 2] == 1;
}
int dir3 = (a * b) & (((x ^ y) & 0x80000000) >> 31);
int dir = a * b + 2 * dir3;
int prev_mag = mag[(lidy + prev[dir][0]) * (GRP_SIZEX + 2) + lidx + prev[dir][1]];
int next_mag = mag[(lidy + next[dir][0]) * (GRP_SIZEX + 2) + lidx + next[dir][1]] + (dir & 1);
if (n > 0)
if (mag0 > prev_mag && mag0 >= next_mag)
{
const int ind = atomic_inc(counter);
st[ind] = (ushort2)(x + 1, y + 1);
value = (mag0 > high_thr) ? 2 : 0;
}
}
storepix(value, map + mad24(gidy, map_step, mad24(gidx, (int)sizeof(int), map_offset)));
}
#elif defined OP_HYST_GLOBAL
#undef TG22
#undef CANNY_SHIFT
__constant int c_dx[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
__constant int c_dy[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
#elif defined STAGE2
/*
stage2:
hysteresis (add edges labeled 0 if they are connected with an edge labeled 2)
*/
#define loadpix(addr) *(__global int *)(addr)
#define storepix(val, addr) *(__global int *)(addr) = (int)(val)
#define l_stack_size 256
#define p_stack_size 8
#define stack_size 512
#define map_index mad24(map_step, pos.y, pos.x * (int)sizeof(int))
__constant short move_dir[2][8] = {
{ -1, -1, -1, 0, 0, 1, 1, 1 },
{ -1, 0, 1, -1, 1, -1, 0, 1 }
};
__kernel void edgesHysteresisGlobal(__global uchar * map, int map_step, int map_offset,
__global ushort2 * st1, __global ushort2 * st2, __global int * counter,
int rows, int cols, int count)
__kernel void stage2_hysteresis(__global uchar *map, int map_step, int map_offset, int rows, int cols)
{
map += map_offset;
int lidx = get_local_id(0);
int x = get_global_id(0);
int y0 = get_global_id(1) * PIX_PER_WI;
int grp_idx = get_group_id(0);
int grp_idy = get_group_id(1);
int lid = get_local_id(0) + get_local_id(1) * 32;
__local unsigned int s_counter, s_ind;
__local ushort2 s_st[stack_size];
__local ushort2 l_stack[l_stack_size];
__local int l_counter;
if (lidx == 0)
s_counter = 0;
if (lid == 0)
l_counter = 0;
barrier(CLK_LOCAL_MEM_FENCE);
int ind = mad24(grp_idy, (int)get_local_size(0), grp_idx);
if (ind < count)
{
ushort2 pos = st1[ind];
if (lidx < 8)
#pragma unroll
for (int y = y0; y < min(y0 + PIX_PER_WI, rows); ++y)
{
pos.x += c_dx[lidx];
pos.y += c_dy[lidx];
if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows && *(__global int *)(map + map_index) == 1)
int type = loadpix(map + mad24(y, map_step, x * (int)sizeof(int)));
if (type == 2)
{
*(__global int *)(map + map_index) = 2;
ind = atomic_inc(&s_counter);
s_st[ind] = pos;
l_stack[atomic_inc(&l_counter)] = (ushort2)(x, y);
}
}
barrier(CLK_LOCAL_MEM_FENCE);
while (s_counter > 0 && s_counter <= stack_size - get_local_size(0))
{
const int subTaskIdx = lidx >> 3;
const int portion = min(s_counter, (uint)(get_local_size(0)>> 3));
ushort2 p_stack[p_stack_size];
int p_counter = 0;
if (subTaskIdx < portion)
pos = s_st[s_counter - 1 - subTaskIdx];
barrier(CLK_LOCAL_MEM_FENCE);
while(l_counter != 0)
{
int mod = l_counter % 64;
int pix_per_thr = l_counter / 64 + (lid < mod) ? 1 : 0;
if (lidx == 0)
s_counter -= portion;
barrier(CLK_LOCAL_MEM_FENCE);
#pragma unroll
for (int i = 0; i < pix_per_thr; ++i)
{
ushort2 pos = l_stack[ atomic_dec(&l_counter) - 1 ];
if (subTaskIdx < portion)
#pragma unroll
for (int j = 0; j < 8; ++j)
{
pos.x += c_dx[lidx & 7];
pos.y += c_dy[lidx & 7];
if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows && *(__global int *)(map + map_index) == 1)
ushort posx = pos.x + move_dir[0][j];
ushort posy = pos.y + move_dir[1][j];
if (posx < 0 || posy < 0 || posx >= cols || posy >= rows)
continue;
__global uchar *addr = map + mad24(posy, map_step, posx * (int)sizeof(int));
int type = loadpix(addr);
if (type == 0)
{
*(__global int *)(map + map_index) = 2;
ind = atomic_inc(&s_counter);
s_st[ind] = pos;
p_stack[p_counter++] = (ushort2)(posx, posy);
storepix(2, addr);
}
}
barrier(CLK_LOCAL_MEM_FENCE);
}
barrier(CLK_LOCAL_MEM_FENCE);
if (s_counter > 0)
while (p_counter > 0)
{
if (lidx == 0)
{
ind = atomic_add(counter, s_counter);
s_ind = ind - s_counter;
l_stack[ atomic_inc(&l_counter) ] = p_stack[--p_counter];
}
barrier(CLK_LOCAL_MEM_FENCE);
ind = s_ind;
for (int i = lidx; i < (int)s_counter; i += get_local_size(0))
st2[ind + i] = s_st[i];
}
}
}
#undef map_index
#undef stack_size
#elif defined OP_EDGES
#elif defined GET_EDGES
// Get the edge result. egde type of value 2 will be marked as an edge point and set to 255. Otherwise 0.
// map edge type mappings
// dst edge output
__kernel void getEdges(__global const uchar * mapptr, int map_step, int map_offset,
__global uchar * dst, int dst_step, int dst_offset, int rows, int cols)
__kernel void getEdges(__global const uchar *mapptr, int map_step, int map_offset, int rows, int cols,
__global uchar *dst, int dst_step, int dst_offset)
{
int x = get_global_id(0);
int y = get_global_id(1);
int y0 = get_global_id(1) * PIX_PER_WI;
if (y < rows && x < cols)
#pragma unroll
for (int y = y0; y < min(y0 + PIX_PER_WI, rows); ++y)
{
int map_index = mad24(map_step, y + 1, mad24(x + 1, (int)sizeof(int), map_offset));
int dst_index = mad24(dst_step, y, x + dst_offset);
int map_index = mad24(map_step, y, mad24(x, (int)sizeof(int), map_offset));
int dst_index = mad24(dst_step, y, x) + dst_offset;
__global const int * map = (__global const int *)(mapptr + map_index);
dst[dst_index] = (uchar)(-(map[0] >> 1));
}
}

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