Prototype OCL version of gaussian blur with integer arithmetic

modules/imgproc/src/opencl/gaussian_blur_8u.cl

+/*M///////////////////////////////////////////////////////////////////////////////////////
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+//                           License Agreement
+//                For Open Source Computer Vision Library
+//
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+//M*/
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////////////////Macro for border type////////////////////////////////////////////
+/////////////////////////////////////////////////////////////////////////////////////////////////
+
+#ifdef BORDER_CONSTANT
+// CCCCCC|abcdefgh|CCCCCCC
+#define EXTRAPOLATE(x, maxV)
+#elif defined BORDER_REPLICATE
+// aaaaaa|abcdefgh|hhhhhhh
+#define EXTRAPOLATE(x, maxV) \
+    { \
+        (x) = max(min((x), (maxV) - 1), 0); \
+    }
+#elif defined BORDER_WRAP
+// cdefgh|abcdefgh|abcdefg
+#define EXTRAPOLATE(x, maxV) \
+    { \
+        (x) = ( (x) + (maxV) ) % (maxV); \
+    }
+#elif defined BORDER_REFLECT
+// fedcba|abcdefgh|hgfedcb
+#define EXTRAPOLATE(x, maxV) \
+    { \
+        (x) = min(((maxV)-1)*2-(x)+1, max((x),-(x)-1) ); \
+    }
+#elif defined BORDER_REFLECT_101 || defined BORDER_REFLECT101
+// gfedcb|abcdefgh|gfedcba
+#define EXTRAPOLATE(x, maxV) \
+    { \
+        (x) = min(((maxV)-1)*2-(x), max((x),-(x)) ); \
+    }
+#else
+#error No extrapolation method
+#endif
+
+#if CN != 3
+#define loadpix(addr) *(__global const srcT *)(addr)
+#define storepix(val, addr)  *(__global dstT *)(addr) = val
+#define SRCSIZE (int)sizeof(srcT)
+#define DSTSIZE (int)sizeof(dstT)
+#else
+#define loadpix(addr)  vload3(0, (__global const srcT1 *)(addr))
+#define storepix(val, addr) vstore3(val, 0, (__global dstT1 *)(addr))
+#define SRCSIZE (int)sizeof(srcT1)*3
+#define DSTSIZE (int)sizeof(dstT1)*3
+#endif
+
+#define SRC(_x,_y) convertToWT(loadpix(Src + mad24(_y, src_step, SRCSIZE * _x)))
+
+#ifdef BORDER_CONSTANT
+// CCCCCC|abcdefgh|CCCCCCC
+#define ELEM(_x,_y,r_edge,t_edge,const_v) (_x)<0 | (_x) >= (r_edge) | (_y)<0 | (_y) >= (t_edge) ? (const_v) : SRC((_x),(_y))
+#else
+#define ELEM(_x,_y,r_edge,t_edge,const_v) SRC((_x),(_y))
+#endif
+
+#define noconvert
+
+// horizontal and vertical filter kernels
+// should be defined on host during compile time to avoid overhead
+#define DIG(a) a,
+__constant int mat_kernelX[] = { KERNEL_MATRIX_X };
+__constant int mat_kernelY[] = { KERNEL_MATRIX_Y };
+
+__kernel void gaussian_blur_8u(__global uchar* Src, int src_step, int srcOffsetX, int srcOffsetY, int height, int width,
+                         __global uchar* Dst, int dst_step, int dst_offset, int dst_rows, int dst_cols)
+{
+    // RADIUSX, RADIUSY are filter dimensions
+    // BLK_X, BLK_Y are local wrogroup sizes
+    // all these should be defined on host during compile time
+    // first lsmem array for source pixels used in first pass,
+    // second lsmemDy for storing first pass results
+    __local WT lsmem[BLK_Y + 2 * RADIUSY][BLK_X + 2 * RADIUSX];
+    __local WT lsmemDy[BLK_Y][BLK_X + 2 * RADIUSX];
+
+    // get local and global ids - used as image and local memory array indexes
+    int lix = get_local_id(0);
+    int liy = get_local_id(1);
+
+    int x = get_global_id(0);
+    int y = get_global_id(1);
+
+    // calculate pixel position in source image taking image offset into account
+    int srcX = x + srcOffsetX - RADIUSX;
+    int srcY = y + srcOffsetY - RADIUSY;
+    int xb = srcX;
+    int yb = srcY;
+
+    // extrapolate coordinates, if needed
+    // and read my own source pixel into local memory
+    // with account for extra border pixels, which will be read by starting workitems
+    int clocY = liy;
+    int cSrcY = srcY;
+    do
+    {
+        int yb = cSrcY;
+        EXTRAPOLATE(yb, (height));
+
+        int clocX = lix;
+        int cSrcX = srcX;
+        do
+        {
+            int xb = cSrcX;
+            EXTRAPOLATE(xb,(width));
+            lsmem[clocY][clocX] = ELEM(xb, yb, (width), (height), 0 );
+
+            clocX += BLK_X;
+            cSrcX += BLK_X;
+        }
+        while(clocX < BLK_X+(RADIUSX*2));
+
+        clocY += BLK_Y;
+        cSrcY += BLK_Y;
+    }
+    while (clocY < BLK_Y+(RADIUSY*2));
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    // do vertical filter pass
+    // and store intermediate results to second local memory array
+    int i, clocX = lix;
+    WT sum = 0;
+    do
+    {
+        sum = 0;
+        for (i=0; i<=2*RADIUSY; i++)
+            sum = mad(lsmem[liy+i][clocX], mat_kernelY[i], sum);
+        lsmemDy[liy][clocX] = sum;
+        clocX += BLK_X;
+    }
+    while(clocX < BLK_X+(RADIUSX*2));
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    // if this pixel happened to be out of image borders because of global size rounding,
+    // then just return
+    if( x >= dst_cols || y >=dst_rows )
+        return;
+
+    // do second horizontal filter pass
+    // and calculate final result
+    sum = 0;
+    for (i=0; i<=2*RADIUSX; i++)
+        sum = mad(lsmemDy[liy][lix+i], mat_kernelX[i], sum);
+    
+    sum = sum >> (GAUSSIAN_COEF_BITS * 2);
+
+    //store result into destination image
+    storepix(convertToDstT(sum), Dst + mad24(y, dst_step, mad24(x, DSTSIZE, dst_offset)));
+}

modules/imgproc/src/smooth.cpp

@@ -42,6 +42,7 @@
 
 #include "precomp.hpp"
 #include "opencl_kernels.hpp"
+#include <iostream>
 
 /*
  * This file includes the code, contributed by Simon Perreault
@@ -1069,6 +1070,73 @@ static void createGaussianKernels( Mat & kx, Mat & ky, int type, Size ksize,
         ky = getGaussianKernel( ksize.height, sigma2, std::max(depth, CV_32F) );
 }
 
+#define GAUSSIAN_COEF_BITS 11
+
+static bool GaussianBlur_8u(InputArray _src, OutputArray _dst, Size ksize,
+                   double sigma1, double sigma2,
+                   int borderType)
+{
+    int type = _src.type();
+    Mat kx, ky;
+    createGaussianKernels(kx, ky, CV_64F, ksize, sigma1, sigma2);
+    Mat kx_8u, ky_8u;
+
+    int scale_coef = 1 << GAUSSIAN_COEF_BITS;
+    kx.convertTo(kx_8u, CV_32S, scale_coef);
+    ky.convertTo(ky_8u, CV_32S, scale_coef);
+
+    kx_8u.reshape(1, 1);
+    ky_8u.reshape(1, 1);
+
+    Size size = _src.size(), wholeSize;
+    Point origin;
+    int stype = _src.type(), sdepth = CV_MAT_DEPTH(stype), cn = CV_MAT_CN(stype),
+            esz = CV_ELEM_SIZE(stype), wdepth = CV_32S,
+            ddepth = sdepth;
+    size_t src_step = _src.step(), src_offset = _src.offset();
+
+    if ((src_offset % src_step) % esz != 0 || !(borderType == BORDER_CONSTANT || borderType == BORDER_REPLICATE ||
+              borderType == BORDER_REFLECT || borderType == BORDER_WRAP ||
+              borderType == BORDER_REFLECT_101))
+        return false;
+
+    size_t lt2[2] = { 16, 16 };
+    size_t gt2[2] = { lt2[0] * (1 + (size.width - 1) / lt2[0]), lt2[1] * (1 + (size.height - 1) / lt2[1]) };
+
+    char cvt[2][40];
+    const char * const borderMap[] = { "BORDER_CONSTANT", "BORDER_REPLICATE", "BORDER_REFLECT", "BORDER_WRAP",
+                                       "BORDER_REFLECT_101" };
+
+    String opts = cv::format("-D BLK_X=%d -D BLK_Y=%d -D RADIUSX=%d -D RADIUSY=%d%s%s"
+                             " -D srcT=%s -D convertToWT=%s -D WT=%s -D dstT=%s -D convertToDstT=%s"
+                             " -D %s -D srcT1=%s -D dstT1=%s -D CN=%d -D GAUSSIAN_COEF_BITS=%d", (int)lt2[0], (int)lt2[1],
+                             kx.rows / 2, kx.rows / 2,
+                             ocl::kernelToStr(kx_8u, CV_32S, "KERNEL_MATRIX_X").c_str(),
+                             ocl::kernelToStr(ky_8u, CV_32S, "KERNEL_MATRIX_Y").c_str(),
+                             ocl::typeToStr(stype), ocl::convertTypeStr(sdepth, wdepth, cn, cvt[0]),
+                             ocl::typeToStr(CV_MAKE_TYPE(wdepth, cn)), ocl::typeToStr(stype),
+                             ocl::convertTypeStr(wdepth, ddepth, cn, cvt[1]), borderMap[borderType],
+                             ocl::typeToStr(sdepth), ocl::typeToStr(ddepth), cn, GAUSSIAN_COEF_BITS);
+
+    ocl::Kernel k("gaussian_blur_8u", ocl::imgproc::gaussian_blur_8u_oclsrc, opts);
+    if (k.empty())
+        return false;
+
+    UMat src = _src.getUMat();
+    _dst.create(size, stype);
+    UMat dst = _dst.getUMat();
+
+    int src_offset_x = static_cast<int>((src_offset % src_step) / esz);
+    int src_offset_y = static_cast<int>(src_offset / src_step);
+
+    src.locateROI(wholeSize, origin);
+
+    k.args(ocl::KernelArg::PtrReadOnly(src), (int)src_step, src_offset_x, src_offset_y,
+        wholeSize.height, wholeSize.width, ocl::KernelArg::WriteOnly(dst));
+
+    return k.run(2, gt2, lt2, false);
+}
+
 }
 
 cv::Ptr<cv::FilterEngine> cv::createGaussianFilter( int type, Size ksize,
@@ -1082,6 +1150,8 @@ cv::Ptr<cv::FilterEngine> cv::createGaussianFilter( int type, Size ksize,
 }
 
 
+
+
 void cv::GaussianBlur( InputArray _src, OutputArray _dst, Size ksize,
                    double sigma1, double sigma2,
                    int borderType )
@@ -1126,6 +1196,13 @@ void cv::GaussianBlur( InputArray _src, OutputArray _dst, Size ksize,
     }
 #endif
 
+    if (type == CV_8U)
+    {
+        CV_OCL_RUN_(_dst.isUMat() && _src.dims() <= 2 && 
+                (!(borderType & BORDER_ISOLATED) || _src.offset() == 0),
+                GaussianBlur_8u(_src, _dst, ksize, sigma1, sigma2, borderType))
+    }
+
     Mat kx, ky;
     createGaussianKernels(kx, ky, type, ksize, sigma1, sigma2);
     sepFilter2D(_src, _dst, CV_MAT_DEPTH(type), kx, ky, Point(-1,-1), 0, borderType );

modules/imgproc/test/ocl/test_filters.cpp

@@ -219,7 +219,23 @@ OCL_TEST_P(GaussianBlurTest, Mat)
         OCL_OFF(cv::GaussianBlur(src_roi, dst_roi, Size(ksize, ksize), sigma1, sigma2, borderType));
         OCL_ON(cv::GaussianBlur(usrc_roi, udst_roi, Size(ksize, ksize), sigma1, sigma2, borderType));
 
-        Near(CV_MAT_DEPTH(type) == CV_8U ? 3 : 5e-5, false);
+
+        if (checkNorm2(dst_roi, udst_roi) > 2 && CV_MAT_DEPTH(type) == CV_8U)
+        {
+            Mat udst = udst_roi.getMat(ACCESS_READ);
+            Mat diff; 
+            absdiff(dst_roi, udst, diff);
+            int nonZero = countNonZero(diff);
+            double max;
+            Point maxn;
+            minMaxLoc(diff, (double*)0, &max, (Point*) 0, &maxn);
+
+            uchar a = dst_roi.at<uchar>(maxn);
+            uchar b = udst.at<uchar>(maxn);
+
+        }
+
+        Near(CV_MAT_DEPTH(type) == CV_8U ? 2 : 5e-5, false);
     }
 }