From 7810254198d53a90b16f0b2e958e884367b543ec Mon Sep 17 00:00:00 2001
From: yao <bitwangyaoyao@gmail.com>
Date: Fri, 22 Feb 2013 15:48:31 +0800
Subject: [PATCH] Fix ocl::equalizeHist mismatch

---
 modules/ocl/src/imgproc.cpp                  |  8 +++++---
 modules/ocl/src/kernels/imgproc_histogram.cl | 13 +++++++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/modules/ocl/src/imgproc.cpp b/modules/ocl/src/imgproc.cpp
index a93f86ecb9..f7d0c43948 100644
--- a/modules/ocl/src/imgproc.cpp
+++ b/modules/ocl/src/imgproc.cpp
@@ -12,6 +12,7 @@
 //
 // Copyright (C) 2010-2012, Institute Of Software Chinese Academy Of Science, all rights reserved.
 // Copyright (C) 2010-2012, Advanced Micro Devices, Inc., all rights reserved.
+// Copyright (C) 2010-2012, Multicoreware, Inc., all rights reserved.
 // Third party copyrights are property of their respective owners.
 //
 // @Authors
@@ -23,6 +24,7 @@
 //    Zhang Ying, zhangying913@gmail.com
 //    Xu Pang, pangxu010@163.com
 //    Wu Zailong, bullet@yeah.net
+//    Wenju He, wenju@multicorewareinc.com
 //
 // Redistribution and use in source and binary forms, with or without modification,
 // are permitted provided that the following conditions are met:
@@ -1524,7 +1526,7 @@ namespace cv
             mat_dst.create(mat_src.rows, mat_src.cols, CV_8UC1);
 
             oclMat mat_hist(1, 256, CV_32SC1);
-            //mat_hist.setTo(0);
+
             calcHist(mat_src, mat_hist);
 
             Context *clCxt = mat_src.clCxt;
@@ -1533,10 +1535,10 @@ namespace cv
             size_t globalThreads[3] = { 256, 1, 1};
             oclMat lut(1, 256, CV_8UC1);
             vector<pair<size_t , const void *> > args;
-            float scale = 255.f / (mat_src.rows * mat_src.cols);
+            int total = mat_src.rows * mat_src.cols;
             args.push_back( make_pair( sizeof(cl_mem), (void *)&lut.data));
             args.push_back( make_pair( sizeof(cl_mem), (void *)&mat_hist.data));
-            args.push_back( make_pair( sizeof(cl_float), (void *)&scale));
+            args.push_back( make_pair( sizeof(int), (void *)&total));
             openCLExecuteKernel(clCxt, &imgproc_histogram, kernelName, globalThreads, localThreads, args, -1, -1);
             LUT(mat_src, lut, mat_dst);
         }
diff --git a/modules/ocl/src/kernels/imgproc_histogram.cl b/modules/ocl/src/kernels/imgproc_histogram.cl
index 11db9b5138..01e333fbc1 100644
--- a/modules/ocl/src/kernels/imgproc_histogram.cl
+++ b/modules/ocl/src/kernels/imgproc_histogram.cl
@@ -3,12 +3,14 @@
 //
 // Copyright (C) 2010-2012, Institute Of Software Chinese Academy Of Science, all rights reserved.
 // Copyright (C) 2010-2012, Advanced Micro Devices, Inc., all rights reserved.
+// Copyright (C) 2010-2012, Multicoreware, Inc., all rights reserved.
 // Third party copyrights are property of their respective owners.
 //
 // @Authors
 //    Niko Li, newlife20080214@gmail.com
 //    Jia Haipeng, jiahaipeng95@gmail.com
 //    Xu Pang, pangxu010@163.com
+//    Wenju He, wenju@multicorewareinc.com
 // Redistribution and use in source and binary forms, with or without modification,
 // are permitted provided that the following conditions are met:
 //
@@ -189,24 +191,27 @@ __kernel __attribute__((reqd_work_group_size(256,1,1)))void merge_hist(__global
 __kernel __attribute__((reqd_work_group_size(256,1,1)))void calLUT(
                             __global uchar * dst,
                             __constant int * hist,
-                            float scale)
+                            int total)
 {
     int lid = get_local_id(0);
-    __local int sumhist[HISTOGRAM256_BIN_COUNT];
-    //__local uchar lut[HISTOGRAM256_BIN_COUNT+1];
+    __local int sumhist[HISTOGRAM256_BIN_COUNT+1];
 
     sumhist[lid]=hist[lid];
     barrier(CLK_LOCAL_MEM_FENCE);
     if(lid==0)
     {
         int sum = 0;
-        for(int i=0;i<HISTOGRAM256_BIN_COUNT;i++)
+        int i = 0;
+        while (!sumhist[i]) ++i;
+        sumhist[HISTOGRAM256_BIN_COUNT] = sumhist[i];
+        for(sumhist[i++] = 0; i<HISTOGRAM256_BIN_COUNT; i++)
         {
             sum+=sumhist[i];
             sumhist[i]=sum;
         }
     }
     barrier(CLK_LOCAL_MEM_FENCE);
+    float scale = 255.f/(total - sumhist[HISTOGRAM256_BIN_COUNT]);
     dst[lid]= lid == 0 ? 0 : convert_uchar_sat(convert_float(sumhist[lid])*scale);
 }
 /*