Add ocl CLACH implementation.

Test cases (accuracy and performance) are provided.

modules/ocl/include/opencv2/ocl/ocl.hpp

@@ -483,6 +483,23 @@ namespace cv
         CV_EXPORTS void calcHist(const oclMat &mat_src, oclMat &mat_hist);
         //! only 8UC1 and 256 bins is supported now
         CV_EXPORTS void equalizeHist(const oclMat &mat_src, oclMat &mat_dst);
+        
+        //! only 8UC1 is supported now
+        class CV_EXPORTS CLAHE
+        {
+        public:
+            virtual void apply(const oclMat &src, oclMat &dst) = 0;
+
+            virtual void setClipLimit(double clipLimit) = 0;
+            virtual double getClipLimit() const = 0;
+
+            virtual void setTilesGridSize(Size tileGridSize) = 0;
+            virtual Size getTilesGridSize() const = 0;
+
+            virtual void collectGarbage() = 0;
+        };
+        CV_EXPORTS Ptr<cv::ocl::CLAHE> createCLAHE(double clipLimit = 40.0, Size tileGridSize = Size(8, 8));
+        
         //! bilateralFilter
         // supports 8UC1 8UC4
         CV_EXPORTS void bilateralFilter(const oclMat& src, oclMat& dst, int d, double sigmaColor, double sigmaSpave, int borderType=BORDER_DEFAULT);

modules/ocl/perf/perf_imgproc.cpp

@@ -921,4 +921,51 @@ PERFTEST(remap)
         }
 
     }
-}
+}
+///////////// CLAHE ////////////////////////
+PERFTEST(CLAHE)
+{
+    Mat src, dst, ocl_dst;
+    cv::ocl::oclMat d_src, d_dst;
+    int all_type[] = {CV_8UC1};
+    std::string type_name[] = {"CV_8UC1"};
+
+    double clipLimit = 40.0;
+
+    cv::Ptr<cv::CLAHE>      clahe   = cv::createCLAHE(clipLimit);
+    cv::Ptr<cv::ocl::CLAHE> d_clahe = cv::ocl::createCLAHE(clipLimit);
+
+    for (int size = Min_Size; size <= Max_Size; size *= Multiple)
+    {
+        for (size_t j = 0; j < sizeof(all_type) / sizeof(int); j++)
+        {
+            SUBTEST << size << 'x' << size << "; " << type_name[j] ;
+
+            gen(src, size, size, all_type[j], 0, 256);
+
+            CPU_ON;
+            clahe->apply(src, dst);
+            CPU_OFF;
+
+            d_src.upload(src);
+
+            WARMUP_ON;
+            d_clahe->apply(d_src, d_dst);
+            WARMUP_OFF;
+
+            ocl_dst = d_dst;
+
+            TestSystem::instance().ExpectedMatNear(dst, ocl_dst, 1.0);
+
+            GPU_ON;
+            d_clahe->apply(d_src, d_dst);
+            GPU_OFF;
+
+            GPU_FULL_ON;
+            d_src.upload(src);
+            d_clahe->apply(d_src, d_dst);
+            d_dst.download(dst);
+            GPU_FULL_OFF;
+        }
+    }
+}

modules/ocl/src/imgproc.cpp

@@ -25,6 +25,7 @@
 //    Xu Pang, pangxu010@163.com
 //    Wu Zailong, bullet@yeah.net
 //    Wenju He, wenju@multicorewareinc.com
+//    Sen Liu, swjtuls1987@126.com
 //
 // Redistribution and use in source and binary forms, with or without modification,
 // are permitted provided that the following conditions are met:
@@ -80,6 +81,7 @@ namespace cv
         extern const char *imgproc_calcHarris;
         extern const char *imgproc_calcMinEigenVal;
         extern const char *imgproc_convolve;
+        extern const char *imgproc_clahe;
         ////////////////////////////////////OpenCL call wrappers////////////////////////////
 
         template <typename T> struct index_and_sizeof;
@@ -1511,6 +1513,189 @@ namespace cv
             openCLExecuteKernel(clCxt, &imgproc_histogram, kernelName, globalThreads, localThreads, args, -1, -1);
             LUT(mat_src, lut, mat_dst);
         }
+
+        ////////////////////////////////////////////////////////////////////////
+        // CLAHE
+        namespace clahe
+        {
+            inline int divUp(int total, int grain)
+            {
+                return (total + grain - 1) / grain * grain;
+            }
+
+            static void calcLut(const oclMat &src, oclMat &dst,
+                const int tilesX, const int tilesY, const cv::Size tileSize,
+                const int clipLimit, const float lutScale)
+            {
+                cl_int2 tile_size;
+                tile_size.s[0] = tileSize.width;
+                tile_size.s[1] = tileSize.height;
+
+                std::vector<pair<size_t , const void *> > args;
+                args.push_back( std::make_pair( sizeof(cl_mem), (void *)&src.data ));
+                args.push_back( std::make_pair( sizeof(cl_mem), (void *)&dst.data ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&src.step ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&dst.step ));
+                args.push_back( std::make_pair( sizeof(cl_int2), (void *)&tile_size ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&tilesX ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&clipLimit ));
+                args.push_back( std::make_pair( sizeof(cl_float), (void *)&lutScale ));
+
+                String kernelName = "calcLut";
+                size_t localThreads[3]  = { 32, 8, 1 };
+                size_t globalThreads[3] = { tilesX * localThreads[0], tilesY * localThreads[1], 1 };
+                bool is_cpu = queryDeviceInfo<IS_CPU_DEVICE, bool>();
+                if (is_cpu)
+                {
+                    openCLExecuteKernel(Context::getContext(), &imgproc_clahe, kernelName, globalThreads, localThreads, args, -1, -1, (char*)" -D CPU");
+                }
+                else
+                {
+                    cl_kernel kernel = openCLGetKernelFromSource(Context::getContext(), &imgproc_clahe, kernelName);
+                    int wave_size = queryDeviceInfo<WAVEFRONT_SIZE, int>(kernel);
+                    openCLSafeCall(clReleaseKernel(kernel));
+
+                    static char opt[20] = {0};
+                    sprintf(opt, " -D WAVE_SIZE=%d", wave_size);
+                    openCLExecuteKernel(Context::getContext(), &imgproc_clahe, kernelName, globalThreads, localThreads, args, -1, -1, opt);
+                }
+            }
+
+            static void transform(const oclMat &src, oclMat &dst, const oclMat &lut,
+                const int tilesX, const int tilesY, const cv::Size tileSize)
+            {
+                cl_int2 tile_size;
+                tile_size.s[0] = tileSize.width;
+                tile_size.s[1] = tileSize.height;
+
+                std::vector<pair<size_t , const void *> > args;
+                args.push_back( std::make_pair( sizeof(cl_mem), (void *)&src.data ));
+                args.push_back( std::make_pair( sizeof(cl_mem), (void *)&dst.data ));
+                args.push_back( std::make_pair( sizeof(cl_mem), (void *)&lut.data ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&src.step ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&dst.step ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&lut.step ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&src.cols ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&src.rows ));
+                args.push_back( std::make_pair( sizeof(cl_int2), (void *)&tile_size ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&tilesX ));
+                args.push_back( std::make_pair( sizeof(cl_int), (void *)&tilesY ));
+
+                String kernelName = "transform";
+                size_t localThreads[3]  = { 32, 8, 1 };
+                size_t globalThreads[3] = { divUp(src.cols, localThreads[0]), divUp(src.rows, localThreads[1]), 1 };
+
+                openCLExecuteKernel(Context::getContext(), &imgproc_clahe, kernelName, globalThreads, localThreads, args, -1, -1);
+            }
+        }
+
+        namespace
+        {
+            class CLAHE_Impl : public cv::ocl::CLAHE
+            {
+            public:
+                CLAHE_Impl(double clipLimit = 40.0, int tilesX = 8, int tilesY = 8);
+
+                cv::AlgorithmInfo* info() const;
+
+                void apply(const oclMat &src, oclMat &dst);
+
+                void setClipLimit(double clipLimit);
+                double getClipLimit() const;
+
+                void setTilesGridSize(cv::Size tileGridSize);
+                cv::Size getTilesGridSize() const;
+
+                void collectGarbage();
+
+            private:
+                double clipLimit_;
+                int tilesX_;
+                int tilesY_;
+
+                oclMat srcExt_;
+                oclMat lut_;
+            };
+
+            CLAHE_Impl::CLAHE_Impl(double clipLimit, int tilesX, int tilesY) :
+            clipLimit_(clipLimit), tilesX_(tilesX), tilesY_(tilesY)
+            {
+            }
+
+            void CLAHE_Impl::apply(const oclMat &src, oclMat &dst)
+            {
+                CV_Assert( src.type() == CV_8UC1 );
+
+                dst.create( src.size(), src.type() );
+
+                const int histSize = 256;
+
+                ensureSizeIsEnough(tilesX_ * tilesY_, histSize, CV_8UC1, lut_);
+
+                cv::Size tileSize;
+                oclMat srcForLut;
+
+                if (src.cols % tilesX_ == 0 && src.rows % tilesY_ == 0)
+                {
+                    tileSize = cv::Size(src.cols / tilesX_, src.rows / tilesY_);
+                    srcForLut = src;
+                }
+                else
+                {
+                    cv::ocl::copyMakeBorder(src, srcExt_, 0, tilesY_ - (src.rows % tilesY_), 0, tilesX_ - (src.cols % tilesX_), cv::BORDER_REFLECT_101, cv::Scalar());
+
+                    tileSize = cv::Size(srcExt_.cols / tilesX_, srcExt_.rows / tilesY_);
+                    srcForLut = srcExt_;
+                }
+
+                const int tileSizeTotal = tileSize.area();
+                const float lutScale = static_cast<float>(histSize - 1) / tileSizeTotal;
+
+                int clipLimit = 0;
+                if (clipLimit_ > 0.0)
+                {
+                    clipLimit = static_cast<int>(clipLimit_ * tileSizeTotal / histSize);
+                    clipLimit = std::max(clipLimit, 1);
+                }
+
+                clahe::calcLut(srcForLut, lut_, tilesX_, tilesY_, tileSize, clipLimit, lutScale);
+                //finish();
+                clahe::transform(src, dst, lut_, tilesX_, tilesY_, tileSize);
+            }
+
+            void CLAHE_Impl::setClipLimit(double clipLimit)
+            {
+                clipLimit_ = clipLimit;
+            }
+
+            double CLAHE_Impl::getClipLimit() const
+            {
+                return clipLimit_;
+            }
+
+            void CLAHE_Impl::setTilesGridSize(cv::Size tileGridSize)
+            {
+                tilesX_ = tileGridSize.width;
+                tilesY_ = tileGridSize.height;
+            }
+
+            cv::Size CLAHE_Impl::getTilesGridSize() const
+            {
+                return cv::Size(tilesX_, tilesY_);
+            }
+
+            void CLAHE_Impl::collectGarbage()
+            {
+                srcExt_.release();
+                lut_.release();
+            }
+        }
+
+        cv::Ptr<cv::ocl::CLAHE> createCLAHE(double clipLimit, cv::Size tileGridSize)
+        {
+            return new CLAHE_Impl(clipLimit, tileGridSize.width, tileGridSize.height);
+        }
+
         //////////////////////////////////bilateralFilter////////////////////////////////////////////////////
         static void
         oclbilateralFilter_8u( const oclMat &src, oclMat &dst, int d,

modules/ocl/src/opencl/imgproc_clahe.cl

@@ -0,0 +1,275 @@
+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                           License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2010-2012, Multicoreware, Inc., all rights reserved.
+// Copyright (C) 2010-2012, Advanced Micro Devices, Inc., all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// @Authors
+//    Sen Liu, swjtuls1987@126.com
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other oclMaterials provided with the distribution.
+//
+//   * The name of the copyright holders may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors as is and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+#ifndef WAVE_SIZE
+#define WAVE_SIZE 1
+#endif
+
+int calc_lut(__local int* smem, int val, int tid)
+{
+    smem[tid] = val;
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid == 0)
+    {
+        for (int i = 1; i < 256; ++i)
+        {
+            smem[i] += smem[i - 1];
+        }
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    return smem[tid];
+}
+
+#ifdef CPU
+void reduce(volatile __local int* smem, int val, int tid)
+{
+    smem[tid] = val;
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 128)
+    { 
+        smem[tid] = val += smem[tid + 128];
+    } 
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 64)
+    { 
+        smem[tid] = val += smem[tid + 64];
+    } 
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 32)
+    {
+        smem[tid] += smem[tid + 32];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 16)
+    {
+        smem[tid] += smem[tid + 16];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 8)
+    {
+        smem[tid] += smem[tid + 8];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 4)
+    {
+        smem[tid] += smem[tid + 4];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 2)
+    {
+        smem[tid] += smem[tid + 2];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 1)
+    {
+        smem[256] = smem[tid] + smem[tid + 1];
+    }
+    barrier(CLK_LOCAL_MEM_FENCE);
+}
+#else
+void reduce(__local volatile int* smem, int val, int tid)
+{
+    smem[tid] = val;
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 128)
+    { 
+        smem[tid] = val += smem[tid + 128];
+    } 
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 64)
+    { 
+        smem[tid] = val += smem[tid + 64];
+    } 
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (tid < 32)
+    {
+        smem[tid] += smem[tid + 32];
+#if WAVE_SIZE < 32
+    } barrier(CLK_LOCAL_MEM_FENCE);
+    if (tid < 16) {
+#endif
+        smem[tid] += smem[tid + 16];
+#if WAVE_SIZE < 16
+    } barrier(CLK_LOCAL_MEM_FENCE);
+    if (tid < 8) {
+#endif
+        smem[tid] += smem[tid + 8];
+        smem[tid] += smem[tid + 4];
+        smem[tid] += smem[tid + 2];
+        smem[tid] += smem[tid + 1];
+    }
+}
+#endif
+
+__kernel void calcLut(__global __const uchar * src, __global uchar * lut,
+                      const int srcStep, const int dstStep,
+                      const int2 tileSize, const int tilesX,
+                      const int clipLimit, const float lutScale)
+{
+    __local int smem[512];
+
+    const int tx = get_group_id(0);
+    const int ty = get_group_id(1);
+    const unsigned int tid = get_local_id(1) * get_local_size(0)
+                             + get_local_id(0);
+
+    smem[tid] = 0;
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    for (int i = get_local_id(1); i < tileSize.y; i += get_local_size(1))
+    {
+        __global const uchar* srcPtr = src + mad24( ty * tileSize.y + i,
+                                                    srcStep, tx * tileSize.x );
+        for (int j = get_local_id(0); j < tileSize.x; j += get_local_size(0))
+        {
+            const int data = srcPtr[j];
+            atomic_inc(&smem[data]);
+        }
+    }
+
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    int tHistVal = smem[tid];
+
+    barrier(CLK_LOCAL_MEM_FENCE);
+
+    if (clipLimit > 0)
+    {
+        // clip histogram bar
+
+        int clipped = 0;
+        if (tHistVal > clipLimit)
+        {
+            clipped = tHistVal - clipLimit;
+            tHistVal = clipLimit;
+        }
+
+        // find number of overall clipped samples
+
+        reduce(smem, clipped, tid);
+        barrier(CLK_LOCAL_MEM_FENCE);
+#ifdef CPU
+        clipped = smem[256];
+#else
+        clipped = smem[0];
+#endif
+
+        // broadcast evaluated value
+
+        __local int totalClipped;
+
+        if (tid == 0)
+            totalClipped = clipped;
+        barrier(CLK_LOCAL_MEM_FENCE);
+
+        // redistribute clipped samples evenly
+
+        int redistBatch = totalClipped / 256;
+        tHistVal += redistBatch;
+
+        int residual = totalClipped - redistBatch * 256;
+        if (tid < residual)
+            ++tHistVal;
+    }
+
+    const int lutVal = calc_lut(smem, tHistVal, tid);
+    uint ires = (uint)convert_int_rte(lutScale * lutVal);
+    lut[(ty * tilesX + tx) * dstStep + tid] =
+        convert_uchar(clamp(ires, (uint)0, (uint)255));
+}
+
+__kernel void transform(__global __const uchar * src,
+                        __global uchar * dst,
+                        __global uchar * lut,
+                        const int srcStep, const int dstStep, const int lutStep,
+                        const int cols, const int rows,
+                        const int2 tileSize,
+                        const int tilesX, const int tilesY)
+{
+    const int x = get_global_id(0);
+    const int y = get_global_id(1);
+
+    if (x >= cols || y >= rows)
+        return;
+
+    const float tyf = (convert_float(y) / tileSize.y) - 0.5f;
+    int ty1 = convert_int_rtn(tyf);
+    int ty2 = ty1 + 1;
+    const float ya = tyf - ty1;
+    ty1 = max(ty1, 0);
+    ty2 = min(ty2, tilesY - 1);
+
+    const float txf = (convert_float(x) / tileSize.x) - 0.5f;
+    int tx1 = convert_int_rtn(txf);
+    int tx2 = tx1 + 1;
+    const float xa = txf - tx1;
+    tx1 = max(tx1, 0);
+    tx2 = min(tx2, tilesX - 1);
+
+    const int srcVal = src[mad24(y, srcStep, x)];
+
+    float res = 0;
+
+    res += lut[mad24(ty1 * tilesX + tx1, lutStep, srcVal)] * ((1.0f - xa) * (1.0f - ya));
+    res += lut[mad24(ty1 * tilesX + tx2, lutStep, srcVal)] * ((xa) * (1.0f - ya));
+    res += lut[mad24(ty2 * tilesX + tx1, lutStep, srcVal)] * ((1.0f - xa) * (ya));
+    res += lut[mad24(ty2 * tilesX + tx2, lutStep, srcVal)] * ((xa) * (ya));
+
+    uint ires = (uint)convert_int_rte(res);
+    dst[mad24(y, dstStep, x)] = convert_uchar(clamp(ires, (uint)0, (uint)255));
+}

modules/ocl/test/test_imgproc.cpp

@@ -23,6 +23,7 @@
 //    Rock Li, Rock.Li@amd.com
 //    Wu Zailong, bullet@yeah.net
 //    Xu Pang, pangxu010@163.com
+//    Sen Liu, swjtuls1987@126.com
 //
 // Redistribution and use in source and binary forms, with or without modification,
 // are permitted provided that the following conditions are met:
@@ -1393,6 +1394,46 @@ TEST_P(calcHist, Mat)
         EXPECT_MAT_NEAR(dst_hist, cpu_hist, 0.0);
     }
 }
+///////////////////////////////////////////////////////////////////////////////////////////////////////
+// CLAHE
+namespace
+{
+    IMPLEMENT_PARAM_CLASS(ClipLimit, double)
+}
+
+PARAM_TEST_CASE(CLAHE, cv::Size, ClipLimit)
+{
+    cv::Size size;
+    double clipLimit;
+
+    cv::Mat src;
+    cv::Mat dst_gold;
+
+    cv::ocl::oclMat g_src;
+    cv::ocl::oclMat g_dst;
+
+    virtual void SetUp()
+    {
+        size = GET_PARAM(0);
+        clipLimit = GET_PARAM(1);
+
+        cv::RNG &rng = TS::ptr()->get_rng();
+        src = randomMat(rng, size, CV_8UC1, 0, 256, false);
+        g_src.upload(src);
+    }
+};
+
+TEST_P(CLAHE, Accuracy)
+{
+    cv::Ptr<cv::ocl::CLAHE> clahe = cv::ocl::createCLAHE(clipLimit);
+    clahe->apply(g_src, g_dst);
+    cv::Mat dst(g_dst);
+
+    cv::Ptr<cv::CLAHE> clahe_gold = cv::createCLAHE(clipLimit);
+    clahe_gold->apply(src, dst_gold);
+
+    EXPECT_MAT_NEAR(dst_gold, dst, 1.0);
+}
 
 ///////////////////////////Convolve//////////////////////////////////
 PARAM_TEST_CASE(ConvolveTestBase, MatType, bool)
@@ -1643,6 +1684,10 @@ INSTANTIATE_TEST_CASE_P(histTestBase, calcHist, Combine(
                             ONE_TYPE(CV_32SC1) //no use
                         ));
 
+INSTANTIATE_TEST_CASE_P(ImgProc, CLAHE, Combine(
+                        Values(cv::Size(128, 128), cv::Size(113, 113), cv::Size(1300, 1300)),
+                        Values(0.0, 40.0)));
+
 //INSTANTIATE_TEST_CASE_P(ConvolveTestBase, Convolve, Combine(
 //                            Values(CV_32FC1, CV_32FC1),
 //                            Values(false))); // Values(false) is the reserved parameter