VFT. Bugs in calculate delta LCH ( sign +/-)

Related Work Items: #8000

1 files changed, 43 insertions, 42 deletions

diff --git a/Software/Visual_Studio/PPC/Modules/Tango.PPC.JobsV2/Dialogs/VectorFineTuningDialogVM.cs b/Software/Visual_Studio/PPC/Modules/Tango.PPC.JobsV2/Dialogs/VectorFineTuningDialogVM.cs
index d6f457a90..5d3ab5504 100644
--- a/Software/Visual_Studio/PPC/Modules/Tango.PPC.JobsV2/Dialogs/VectorFineTuningDialogVM.cs
+++ b/Software/Visual_Studio/PPC/Modules/Tango.PPC.JobsV2/Dialogs/VectorFineTuningDialogVM.cs
@@ -1577,53 +1577,54 @@ namespace Tango.PPC.Jobs.Dialogs
 
         double DeltaE_CMC(double L1, double a1, double b1, double L2, double a2, double b2, out double dL, out double dC, out double dH)
         {
-            double h1 = Math.Atan2(b1, a1) * (180 / Math.PI);
-            if (h1 < 0)
-                h1 = h1 + 360;
-            double h2 = Math.Atan2(b2, a2) * (180 / Math.PI);
-            if (h2 < 0)
-                h2 = h2 + 360;
-            double refX_H = h1;
-            //chroma calculation
-            double refX_C = Math.Sqrt(a1 * a1 + b1 * b1);
-            //reference SL parameter
-            double refX_SL;
-            if (L1 <= 16)
-                refX_SL = 0.511;
+            double SL;
+            if (L1 < 16)
+                SL = 0.511;
             else
-                refX_SL = L1 * 0.040975 / (1 + 0.01765 * L1);
-            //reference SC parameter
-            double refX_SC = (0.638 + 0.0638 * refX_C / (1 + 0.0131 * refX_C));
-            //reference CQ parameter
-            double refX_CQ = Math.Pow(refX_C, 4);
-            //reference F parameter
-            double refX_F = Math.Sqrt(refX_CQ / (refX_CQ + 1900));
-            // reference T parameter
-            double refX_T = 0;
-            if ((refX_H > 164) & (refX_H < 345))
-                refX_T = 0.56 + Math.Abs(0.2 * Math.Cos(Math.PI * (refX_H + 168) / 180));
-            else if ((refX_H >= 345) | (refX_H <= 164))
-                refX_T = 0.36 + Math.Abs(0.4 * Math.Cos(Math.PI * (refX_H + 35) / 180));
-            // reference SH parameter
-            double refX_SH = refX_SC * (refX_T * refX_F + 1 - refX_F);
+                SL = L1 * 0.040975 / (1 + 0.01765 * L1);
 
-            //sample parameter calculations
-            //hue calculation
-            double samX_H = h2;
-            //chroma calculation     
-            double samX_C = Math.Sqrt(a2 * a2 + b2 * b2);
+            //chroma calculation
+            double C1 = Math.Sqrt(a1 * a1 + b1 * b1);
+            double C2 = Math.Sqrt(a2 * a2 + b2 * b2);
+            var deltaC = C1 - C2;
+            
+            double SC = (0.0638 * C1 / (1 + 0.0131 * C1)) + 0.638;
+            
+            double C1_P4 = Math.Pow(C1, 4);
+            double F = Math.Sqrt(C1_P4 / (C1_P4 + 1900));
+            
+            double H1 = Math.Atan2(b1, a1) * (180 / Math.PI);
+            if (H1 < 0)
+                H1 = H1 + 360;
 
-            var dl = L1 - L2;
-            var dc = samX_C - refX_C;
-            double da = a1 - a2;
-            double db = b1 - b2;
-            var dh = Math.Sqrt(Math.Max(da * da + db * db - dc * dc, 0.0));
+            double T;
+            if ((H1 >= 164) & (H1 <= 345))
+                T = 0.56 + Math.Abs(0.2 * Math.Cos((H1 + 168) *Math.PI / 180));
+            else //if ((H1 > 345) | (H1 < 164))
+                T = 0.36 + Math.Abs(0.4 * Math.Cos((H1 + 35) *Math.PI / 180));
+            
+            double SH = SC * (T * F + 1 - F);
+              
+            var deltaL = L1 - L2;
+             //hue calculation
+            double delta_a = a1 - a2;
+            double delta_b = b1 - b2;
+            var deltaH = Math.Sqrt(Math.Max(delta_a * delta_a + delta_b * delta_b - deltaC * deltaC, 0.0));
 
-            double dECMC = Math.Sqrt(Math.Pow(dl / (2 * refX_SL), 2) + Math.Pow(dc / refX_SC, 2) + Math.Pow(dh / refX_SH, 2));
+            double dECMC = Math.Sqrt(Math.Pow(deltaL / (2 * SL), 2) + Math.Pow(deltaC / SC, 2) + Math.Pow(deltaH / SH, 2));
 
-            dL = (dl / (2 * refX_SL));
-            dC = (dc / refX_SC);
-            dH = (dh / refX_SH);
+            dL = (deltaL / (2 * SL));
+            dC = (deltaC / SC);
+            
+            LabColor labColor = new LabColor(L1, a1, b1);
+            LabColor trget_labColor = new LabColor(L2, a2, b2);
+            var converter = new ColourfulConverter { WhitePoint = Illuminants.D65 };
+            var LCH_input = converter.ToLChab(labColor);
+            var LCH_target = converter.ToLChab(trget_labColor);
+            if(LCH_target.h > LCH_input.h)
+                dH = (deltaH / SH) * (-1);
+            else
+                dH = (deltaH / SH);
 
             return dECMC;