diff --git a/modules/imgproc/src/canny.cpp b/modules/imgproc/src/canny.cpp
index cf2c6bb294..fa751c9108 100644
--- a/modules/imgproc/src/canny.cpp
+++ b/modules/imgproc/src/canny.cpp
@@ -195,20 +195,20 @@ static bool ocl_Canny(InputArray _src, OutputArray _dst, float low_thresh, float
             hysteresis (add weak edges if they are connected with strong edges)
     */
 
+    int sizey = lSizeY / PIX_PER_WI;
+    if (sizey == 0)
+        sizey = 1;
+
+    size_t globalsize[2] = { size.width, (size.height + PIX_PER_WI - 1) / PIX_PER_WI }, localsize[2] = { lSizeX, sizey };
+
     ocl::Kernel edgesHysteresis("stage2_hysteresis", ocl::imgproc::canny_oclsrc,
-                                format("-D STAGE2 -D PIX_PER_WI=%d", PIX_PER_WI));
+                                format("-D STAGE2 -D PIX_PER_WI=%d -D LOCAL_X=%d -D LOCAL_Y=%d",
+                                PIX_PER_WI, lSizeX, sizey));
 
     if (edgesHysteresis.empty())
         return false;
 
     edgesHysteresis.args(ocl::KernelArg::ReadWrite(map));
-
-    int sizey = lSizeY / PIX_PER_WI;
-    if (sizey == 0)
-        sizey = 1;
-
-    size_t globalsize[2] = { size.width, size.height / PIX_PER_WI }, localsize[2] = { lSizeX, sizey };
-
     if (!edgesHysteresis.run(2, globalsize, localsize, false))
         return false;
 
diff --git a/modules/imgproc/src/deriv.cpp b/modules/imgproc/src/deriv.cpp
index dd8f124e5b..068461a8c3 100644
--- a/modules/imgproc/src/deriv.cpp
+++ b/modules/imgproc/src/deriv.cpp
@@ -671,16 +671,20 @@ static bool ocl_Laplacian5(InputArray _src, OutputArray _dst,
 
     size_t wgs = dev.maxWorkGroupSize();
     size_t lmsz = dev.localMemSize();
-
     size_t src_step = _src.step(), src_offset = _src.offset();
+    const size_t tileSizeYmax = wgs / tileSizeX;
+
+    // workaround for Nvidia: 3 channel vector type takes 4*elem_size in local memory
+    int loc_mem_cn = dev.vendorID() == ocl::Device::VENDOR_NVIDIA && cn == 3 ? 4 : cn;
+
     if (((src_offset % src_step) % esz == 0) &&
         (
          (borderType == BORDER_CONSTANT || borderType == BORDER_REPLICATE) ||
          ((borderType == BORDER_REFLECT || borderType == BORDER_WRAP || borderType == BORDER_REFLECT_101) &&
-          (_src.cols() >= kernelX.cols && _src.rows() >= kernelY.cols))
+          (_src.cols() >= (int) (kernelX.cols + tileSizeX) && _src.rows() >= (int) (kernelY.cols + tileSizeYmax)))
         ) &&
-        (tileSizeX * tileSizeYmin  <= wgs) &&
-        (LAPLACIAN_LOCAL_MEM(tileSizeX, tileSizeYmin, kernelX.cols, cn * 4) <= lmsz)
+        (tileSizeX * tileSizeYmin <= wgs) &&
+        (LAPLACIAN_LOCAL_MEM(tileSizeX, tileSizeYmin, kernelX.cols, loc_mem_cn * 4) <= lmsz)
        )
     {
         Size size = _src.size(), wholeSize;
@@ -688,8 +692,8 @@ static bool ocl_Laplacian5(InputArray _src, OutputArray _dst,
         int dtype = CV_MAKE_TYPE(ddepth, cn);
         int wdepth = CV_32F;
 
-        size_t tileSizeY = wgs / tileSizeX;
-        while ((tileSizeX * tileSizeY > wgs) || (LAPLACIAN_LOCAL_MEM(tileSizeX, tileSizeY, kernelX.cols, cn * 4) > lmsz))
+        size_t tileSizeY = tileSizeYmax;
+        while ((tileSizeX * tileSizeY > wgs) || (LAPLACIAN_LOCAL_MEM(tileSizeX, tileSizeY, kernelX.cols, loc_mem_cn * 4) > lmsz))
         {
             tileSizeY /= 2;
         }
diff --git a/modules/imgproc/src/opencl/canny.cl b/modules/imgproc/src/opencl/canny.cl
index da2750e348..dd455d04b5 100644
--- a/modules/imgproc/src/opencl/canny.cl
+++ b/modules/imgproc/src/opencl/canny.cl
@@ -375,7 +375,8 @@ __kernel void stage1_without_sobel(__global const uchar *dxptr, int dx_step, int
 
 #define loadpix(addr) *(__global int *)(addr)
 #define storepix(val, addr) *(__global int *)(addr) = (int)(val)
-#define l_stack_size 256
+#define LOCAL_TOTAL (LOCAL_X*LOCAL_Y)
+#define l_stack_size (4*LOCAL_TOTAL)
 #define p_stack_size 8
 
 __constant short move_dir[2][8] = {
@@ -390,7 +391,7 @@ __kernel void stage2_hysteresis(__global uchar *map, int map_step, int map_offse
     int x = get_global_id(0);
     int y0 = get_global_id(1) * PIX_PER_WI;
 
-    int lid = get_local_id(0) + get_local_id(1) * 32;
+    int lid = get_local_id(0) + get_local_id(1) * LOCAL_X;
 
     __local ushort2 l_stack[l_stack_size];
     __local int l_counter;
@@ -402,10 +403,13 @@ __kernel void stage2_hysteresis(__global uchar *map, int map_step, int map_offse
     #pragma unroll
     for (int y = y0; y < min(y0 + PIX_PER_WI, rows); ++y)
     {
-        int type = loadpix(map + mad24(y, map_step, x * (int)sizeof(int)));
-        if (type == 2)
+        if (x < cols)
         {
-            l_stack[atomic_inc(&l_counter)] = (ushort2)(x, y);
+            int type = loadpix(map + mad24(y, map_step, x * (int)sizeof(int)));
+            if (type == 2)
+            {
+                l_stack[atomic_inc(&l_counter)] = (ushort2)(x, y);
+            }
         }
     }
     barrier(CLK_LOCAL_MEM_FENCE);
@@ -415,8 +419,8 @@ __kernel void stage2_hysteresis(__global uchar *map, int map_step, int map_offse
 
     while(l_counter != 0)
     {
-        int mod = l_counter % 64;
-        int pix_per_thr = l_counter / 64 + (lid < mod) ? 1 : 0;
+        int mod = l_counter % LOCAL_TOTAL;
+        int pix_per_thr = l_counter / LOCAL_TOTAL + ((lid < mod) ? 1 : 0);
 
         #pragma unroll
         for (int i = 0; i < pix_per_thr; ++i)
diff --git a/modules/imgproc/src/opencl/covardata.cl b/modules/imgproc/src/opencl/covardata.cl
index 8aee637da9..8f67d8ffe7 100644
--- a/modules/imgproc/src/opencl/covardata.cl
+++ b/modules/imgproc/src/opencl/covardata.cl
@@ -16,7 +16,7 @@
 //aaaaaa|abcdefgh|hhhhhhh
 #define EXTRAPOLATE(x, maxV) \
     { \
-        (x) = max(min((x), (maxV) - 1), 0); \
+        (x) = clamp((x), 0, (maxV)-1); \
     }
 #elif defined BORDER_WRAP
 //cdefgh|abcdefgh|abcdefg
diff --git a/modules/imgproc/src/opencl/filterSep_singlePass.cl b/modules/imgproc/src/opencl/filterSep_singlePass.cl
index 8c14f2d77e..1f96d7d6e1 100644
--- a/modules/imgproc/src/opencl/filterSep_singlePass.cl
+++ b/modules/imgproc/src/opencl/filterSep_singlePass.cl
@@ -50,7 +50,7 @@
 // aaaaaa|abcdefgh|hhhhhhh
 #define EXTRAPOLATE(x, maxV) \
     { \
-        (x) = max(min((x), (maxV) - 1), 0); \
+        (x) = clamp((x), 0, (maxV)-1); \
     }
 #elif defined BORDER_WRAP
 // cdefgh|abcdefgh|abcdefg
diff --git a/modules/imgproc/src/opencl/laplacian5.cl b/modules/imgproc/src/opencl/laplacian5.cl
index ed6a0d4263..1404a8c51e 100644
--- a/modules/imgproc/src/opencl/laplacian5.cl
+++ b/modules/imgproc/src/opencl/laplacian5.cl
@@ -49,7 +49,7 @@ __kernel void sumConvert(__global const uchar * src1ptr, int src1_step, int src1
 // aaaaaa|abcdefgh|hhhhhhh
 #define EXTRAPOLATE(x, maxV) \
     { \
-        (x) = max(min((x), (maxV) - 1), 0); \
+        (x) = clamp((x), 0, (maxV)-1); \
     }
 #elif defined BORDER_WRAP
 // cdefgh|abcdefgh|abcdefg