Merge pull request #12279 from savuor:cvtcolor_bgr2gray_8u_15bits

* bgr2gray 8u fixed to be in conformance with IPP code

* coefficients fixed so their sum is 32768

* java test for CascadeDetect fixed: equalizeHist added

modules/imgproc/src/color.hpp

@@ -22,11 +22,15 @@ const float R2YF = 0.299f;
 
 enum
 {
+    gray_shift = 15,
     yuv_shift = 14,
     xyz_shift = 12,
     R2Y = 4899, // == R2YF*16384
     G2Y = 9617, // == G2YF*16384
     B2Y = 1868, // == B2YF*16384
+    RY15 =  9798, // == R2YF*32768 + 0.5
+    GY15 = 19235, // == G2YF*32768 + 0.5
+    BY15 =  3735, // == B2YF*32768 + 0.5
     BLOCK_SIZE = 256
 };
 

modules/imgproc/src/color_rgb.cpp

@@ -717,10 +717,10 @@ template<> struct RGB2Gray<uchar>
 
     RGB2Gray(int _srccn, int blueIdx, const int* coeffs) : srccn(_srccn)
     {
-        const int coeffs0[] = { R2Y, G2Y, B2Y };
+        const int coeffs0[] = { RY15, GY15, BY15 };
         if(!coeffs) coeffs = coeffs0;
 
-        int b = 0, g = 0, r = (1 << (yuv_shift-1));
+        int b = 0, g = 0, r = (1 << (gray_shift-1));
         int db = coeffs[blueIdx^2], dg = coeffs[1], dr = coeffs[blueIdx];
 
         for( int i = 0; i < 256; i++, b += db, g += dg, r += dr )
@@ -735,7 +735,7 @@ template<> struct RGB2Gray<uchar>
         int scn = srccn;
         const int* _tab = tab;
         for(int i = 0; i < n; i++, src += scn)
-            dst[i] = (uchar)((_tab[src[0]] + _tab[src[1]+256] + _tab[src[2]+512]) >> yuv_shift);
+            dst[i] = (uchar)((_tab[src[0]] + _tab[src[1]+256] + _tab[src[2]+512]) >> gray_shift);
     }
     int srccn;
     int tab[256*3];

modules/imgproc/src/opencl/color_rgb.cl

@@ -75,10 +75,14 @@
 
 enum
 {
+    gray_shift = 15,
     yuv_shift  = 14,
     R2Y        = 4899,
     G2Y        = 9617,
-    B2Y        = 1868
+    B2Y        = 1868,
+    RY15 = 9798,  // == R2YF*32768 + 0.5
+    GY15 = 19235, // == G2YF*32768 + 0.5
+    BY15 = 3735   // == B2YF*32768 + 0.5
 };
 
 //constants for conversion from/to RGB and Gray, YUV, YCrCb according to BT.601
@@ -129,6 +133,8 @@ __kernel void RGB2Gray(__global const uchar * srcptr, int src_step, int src_offs
                 DATA_TYPE_3 src_pix = vload3(0, src);
 #ifdef DEPTH_5
                 dst[0] = fma(src_pix.B_COMP, B2YF, fma(src_pix.G_COMP, G2YF, src_pix.R_COMP * R2YF));
+#elif defined(DEPTH_0)
+                dst[0] = (DATA_TYPE)CV_DESCALE(mad24(src_pix.B_COMP, BY15, mad24(src_pix.G_COMP, GY15, mul24(src_pix.R_COMP, RY15))), gray_shift);
 #else
                 dst[0] = (DATA_TYPE)CV_DESCALE(mad24(src_pix.B_COMP, B2Y, mad24(src_pix.G_COMP, G2Y, mul24(src_pix.R_COMP, R2Y))), yuv_shift);
 #endif

modules/objdetect/misc/java/test/CascadeClassifierTest.java

@@ -36,9 +36,9 @@ public class CascadeClassifierTest extends OpenCVTestCase {
 
         Mat greyLena = new Mat();
         Imgproc.cvtColor(rgbLena, greyLena, Imgproc.COLOR_RGB2GRAY);
+        Imgproc.equalizeHist(greyLena, greyLena);
 
-        // TODO: doesn't detect with 1.1 scale
-        cc.detectMultiScale(greyLena, faces, 1.09, 3, Objdetect.CASCADE_SCALE_IMAGE, new Size(30, 30), new Size());
+        cc.detectMultiScale(greyLena, faces, 1.1, 3, Objdetect.CASCADE_SCALE_IMAGE, new Size(30, 30), new Size());
         assertEquals(1, faces.total());
     }