From 30926a23dbdd0eca4141c818af8ef2ca11fe3881 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Thu, 15 Sep 2016 16:00:07 +1000
Subject: [PATCH] Add Robinson edge detection operator

Former-commit-id: 1a1c53bdeb6a5a6040ea2da8202693689a8004a4
Former-commit-id: af63533f9f04e814c10bb41a456217fa569846f5
Former-commit-id: cfa93ef57fea2c3c24da41c9da4b7153c91c7d90
---
 README.md                                     |  1 +
 .../Filters/Options/EdgeDetection.cs          |  5 ++
 .../Samplers/DetectEdges.cs                   |  4 +
 .../EdgeDetection/RobinsonProcessor.cs        | 82 +++++++++++++++++++
 .../Processors/Samplers/DetectEdgesTest.cs    |  3 +-
 5 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 src/ImageProcessorCore/Samplers/Processors/Convolution/EdgeDetection/RobinsonProcessor.cs

diff --git a/README.md b/README.md
index c8196c8a5..3caa42b6a 100644
--- a/README.md
+++ b/README.md
@@ -129,6 +129,7 @@ git clone https://github.com/JimBobSquarePants/ImageProcessor
  - [x] LaplacianOfGaussian
  - [x] Prewitt
  - [x] RobertsCross
+ - [x] Robinson
  - [x] Scharr
  - [x] Sobel
 - Blurring/Sharpening
diff --git a/src/ImageProcessorCore/Filters/Options/EdgeDetection.cs b/src/ImageProcessorCore/Filters/Options/EdgeDetection.cs
index f637e4573..0132b10e3 100644
--- a/src/ImageProcessorCore/Filters/Options/EdgeDetection.cs
+++ b/src/ImageProcessorCore/Filters/Options/EdgeDetection.cs
@@ -45,6 +45,11 @@ namespace ImageProcessorCore
         /// </summary>
         RobertsCross,
 
+        /// <summary>
+        /// The Robinson operator filter.
+        /// </summary>
+        Robinson,
+
         /// <summary>
         /// The Scharr operator filter.
         /// </summary>
diff --git a/src/ImageProcessorCore/Samplers/DetectEdges.cs b/src/ImageProcessorCore/Samplers/DetectEdges.cs
index 60006ea72..5281db031 100644
--- a/src/ImageProcessorCore/Samplers/DetectEdges.cs
+++ b/src/ImageProcessorCore/Samplers/DetectEdges.cs
@@ -113,6 +113,10 @@ namespace ImageProcessorCore
                     processor = new RobertsCrossProcessor<TColor, TPacked> { Grayscale = grayscale };
                     break;
 
+                case EdgeDetection.Robinson:
+                    processor = new RobinsonProcessor<TColor, TPacked> { Grayscale = grayscale };
+                    break;
+
                 case EdgeDetection.Scharr:
                     processor = new ScharrProcessor<TColor, TPacked> { Grayscale = grayscale };
                     break;
diff --git a/src/ImageProcessorCore/Samplers/Processors/Convolution/EdgeDetection/RobinsonProcessor.cs b/src/ImageProcessorCore/Samplers/Processors/Convolution/EdgeDetection/RobinsonProcessor.cs
new file mode 100644
index 000000000..31845b4f8
--- /dev/null
+++ b/src/ImageProcessorCore/Samplers/Processors/Convolution/EdgeDetection/RobinsonProcessor.cs
@@ -0,0 +1,82 @@
+// <copyright file="RobinsonProcessor.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessorCore.Processors
+{
+    /// <summary>
+    /// The Kirsch operator filter.
+    /// <see href="http://www.tutorialspoint.com/dip/Robinson_Compass_Mask.htm"/>
+    /// </summary>
+    /// <typeparam name="TColor">The pixel format.</typeparam>
+    /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
+    public class RobinsonProcessor<TColor, TPacked> : EdgeDetectorCompassFilter<TColor, TPacked>
+        where TColor : IPackedVector<TPacked>
+        where TPacked : struct
+    {
+        /// <inheritdoc/>
+        public override float[,] North => new float[,]
+        {
+            { 1, 2, 1 },
+            { 0,  0, 0 },
+            { -1, -2, -1 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] NorthWest => new float[,]
+        {
+            { 2,  1, 0 },
+            { 1,  0, -1 },
+            { 0, -1, -2 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] West => new float[,]
+        {
+            { 1, 0, -1 },
+            { 2, 0, -2 },
+            { 1, 0, -1 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] SouthWest => new float[,]
+        {
+            { 0, -1, -2 },
+            { 1, 0, -1 },
+            { 2, 1,  0 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] South => new float[,]
+        {
+            { -1, -2, -1 },
+            { 0,  0, 0 },
+            { 1,  2,  1 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] SouthEast => new float[,]
+        {
+            { -2, -1, 0 },
+            { -1,  0, 1 },
+            { 0,  1,  2 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] East => new float[,]
+        {
+            { -1, 0, 1 },
+            { -2, 0, 2 },
+            { -1, 0, 1 }
+        };
+
+        /// <inheritdoc/>
+        public override float[,] NorthEast => new float[,]
+        {
+            { 0,  1,  2 },
+            { -1,  0, 1 },
+            { -2, -1, 0 }
+        };
+    }
+}
\ No newline at end of file
diff --git a/tests/ImageProcessorCore.Tests/Processors/Samplers/DetectEdgesTest.cs b/tests/ImageProcessorCore.Tests/Processors/Samplers/DetectEdgesTest.cs
index fde41b5d8..71896b6ef 100644
--- a/tests/ImageProcessorCore.Tests/Processors/Samplers/DetectEdgesTest.cs
+++ b/tests/ImageProcessorCore.Tests/Processors/Samplers/DetectEdgesTest.cs
@@ -21,12 +21,13 @@ namespace ImageProcessorCore.Tests
             EdgeDetection.LaplacianOfGaussian,
             EdgeDetection.Prewitt,
             EdgeDetection.RobertsCross,
+            EdgeDetection.Robinson,
             EdgeDetection.Scharr,
             EdgeDetection.Sobel,
         };
 
         [Theory]
-        [MemberData("DetectEdgesFilters")]
+        [MemberData(nameof(DetectEdgesFilters))]
         public void ImageShouldApplyDetectEdgesFilter(EdgeDetection detector)
         {
             const string path = "TestOutput/DetectEdges";