Clean up Gaussian Blur.

Remove old code. Something is still not right here with smoothing not
even.


Former-commit-id: f1d5ac17714dbbf71aae5de61f7ed3c4538934ed
Former-commit-id: ec7f0d53d5ef132102808bcef83aea84453b0387
Former-commit-id: 81ca8195d1c72810e776de098086c00dc7aeecfc

src/ImageProcessor/Filters/Convolution/Convolution2DFilter - Copy.cs

@@ -1,99 +0,0 @@
-// <copyright file="Convolution2DFilter.cs" company="James South">
-// Copyright (c) James South and contributors.
-// Licensed under the Apache License, Version 2.0.
-// </copyright>
-
-namespace ImageProcessor.Filters
-{
-    using System;
-    using System.Threading.Tasks;
-
-    /// <summary>
-    /// Defines a filter that uses a matrix to perform convolution across two dimensions against an image.
-    /// </summary>
-    public abstract class Convolution2DFilter : ParallelImageProcessor
-    {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
-        public abstract float[,] KernelX { get; }
-
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
-        public abstract float[,] KernelY { get; }
-
-        /// <inheritdoc/>
-        protected override void Apply(ImageBase target, ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle, int startY, int endY)
-        {
-            float[,] kernelX = this.KernelX;
-            float[,] kernelY = this.KernelY;
-            int kernelYLength = kernelY.GetLength(0);
-            int kernelXLength = kernelX.GetLength(0);
-            int radiusY = kernelYLength >> 1;
-            int radiusX = kernelXLength >> 1;
-
-            int sourceY = sourceRectangle.Y;
-            int sourceBottom = sourceRectangle.Bottom;
-            int startX = sourceRectangle.X;
-            int endX = sourceRectangle.Right;
-            int maxY = sourceBottom - 1;
-            int maxX = endX - 1;
-
-            Parallel.For(
-                startY,
-                endY,
-                y =>
-                {
-                    if (y >= sourceY && y < sourceBottom)
-                    {
-                        for (int x = startX; x < endX; x++)
-                        {
-                            float rX = 0;
-                            float gX = 0;
-                            float bX = 0;
-                            float rY = 0;
-                            float gY = 0;
-                            float bY = 0;
-
-                            // Apply each matrix multiplier to the color components for each pixel.
-                            for (int fy = 0; fy < kernelYLength; fy++)
-                            {
-                                int fyr = fy - radiusY;
-                                int offsetY = y + fyr;
-
-                                offsetY = offsetY.Clamp(0, maxY);
-
-                                for (int fx = 0; fx < kernelXLength; fx++)
-                                {
-                                    int fxr = fx - radiusX;
-                                    int offsetX = x + fxr;
-
-                                    offsetX = offsetX.Clamp(0, maxX);
-                                 
-                                    Color currentColor = source[offsetX, offsetY];
-                                    float r = currentColor.R;
-                                    float g = currentColor.G;
-                                    float b = currentColor.B;
-
-                                    rX += kernelX[fx, fy] * r;
-                                    gX += kernelX[fx, fy] * g;
-                                    bX += kernelX[fx, fy] * b;
-
-                                    rY += kernelY[fy, fx] * r;
-                                    gY += kernelY[fy, fx] * g;
-                                    bY += kernelY[fy, fx] * b;
-                                }
-                            }
-
-                            float red = (float)Math.Sqrt((rX * rX) + (rY * rY));
-                            float green = (float)Math.Sqrt((gX * gX) + (gY * gY));
-                            float blue = (float)Math.Sqrt((bX * bX) + (bY * bY));
-
-                            target[x, y] = new Color(red, green, blue);
-                        }
-                    }
-                });
-        }
-    }
-}

src/ImageProcessor/Filters/Convolution/Convolution2DFilter.cs

@@ -28,8 +28,12 @@ namespace ImageProcessor.Filters
         {
             float[,] kernelX = this.KernelX;
             float[,] kernelY = this.KernelY;
-            int kernelLength = kernelX.GetLength(0);
+            int kernelYHeight = kernelY.GetLength(0);
-            int radius = kernelLength >> 1;
+            int kernelYWidth = kernelY.GetLength(1);
+            int kernelXHeight = kernelX.GetLength(0);
+            int kernelXWidth = kernelX.GetLength(0);
+            int radiusY = kernelYHeight >> 1;
+            int radiusX = kernelXWidth >> 1;
 
             int sourceY = sourceRectangle.Y;
             int sourceBottom = sourceRectangle.Bottom;
@@ -55,16 +59,16 @@ namespace ImageProcessor.Filters
                             float bY = 0;
 
                             // Apply each matrix multiplier to the color components for each pixel.
-                            for (int fy = 0; fy < kernelLength; fy++)
+                            for (int fy = 0; fy < kernelYHeight; fy++)
                             {
-                                int fyr = fy - radius;
+                                int fyr = fy - radiusY;
                                 int offsetY = y + fyr;
 
                                 offsetY = offsetY.Clamp(0, maxY);
 
-                                for (int fx = 0; fx < kernelLength; fx++)
+                                for (int fx = 0; fx < kernelXWidth; fx++)
                                 {
-                                    int fxr = fx - radius;
+                                    int fxr = fx - radiusX;
                                     int offsetX = x + fxr;
 
                                     offsetX = offsetX.Clamp(0, maxX);
@@ -74,13 +78,19 @@ namespace ImageProcessor.Filters
                                     float g = currentColor.G;
                                     float b = currentColor.B;
 
-                                    rX += kernelX[fy, fx] * r;
+                                    if (fy < kernelXHeight)
-                                    gX += kernelX[fy, fx] * g;
+                                    {
-                                    bX += kernelX[fy, fx] * b;
+                                        rX += kernelX[fy, fx] * r;
+                                        gX += kernelX[fy, fx] * g;
+                                        bX += kernelX[fy, fx] * b;
+                                    }
 
-                                    rY += kernelY[fy, fx] * r;
+                                    if (fx < kernelYWidth)
-                                    gY += kernelY[fy, fx] * g;
+                                    {
-                                    bY += kernelY[fy, fx] * b;
+                                        rY += kernelY[fy, fx] * r;
+                                        gY += kernelY[fy, fx] * g;
+                                        bY += kernelY[fy, fx] * b;
+                                    }
                                 }
                             }
 

src/ImageProcessor/Filters/Convolution/GuassianBlur.cs

@@ -1,28 +1,47 @@
-namespace ImageProcessor.Filters.Convolution
+// <copyright file="GuassianBlur.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
 {
     using System;
 
+    /// <summary>
+    /// Applies a Gaussian blur to the image.
+    /// TODO: Something is not right here. The output blur is more like a motion blur.
+    /// </summary>
     public class GuassianBlur : Convolution2DFilter
     {
-        private int kernelSize;
+        /// <summary>
+        /// The maximum size of the kernal in either direction.
+        /// </summary>
+        private readonly int kernelSize;
 
-        private float standardDeviation;
+        /// <summary>
+        /// The standard deviation (weight)
+        /// </summary>
+        private readonly float standardDeviation;
 
+        /// <summary>
+        /// The vertical kernel
+        /// </summary>
         private float[,] kernelY;
+
+        /// <summary>
+        /// The horizontal kernel
+        /// </summary>
         private float[,] kernelX;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="GuassianBlur"/> class.
         /// </summary>
-        /// <param name="size">
-        /// The size.
-        /// </param>
         /// <param name="standardDeviation">
         /// The standard deviation 'sigma' value for calculating Gaussian curves.
         /// </param>
-        public GuassianBlur(int size, float standardDeviation = 1.4f)
+        public GuassianBlur(float standardDeviation = 3f)
         {
-            this.kernelSize = size;
+            this.kernelSize = ((int)Math.Ceiling(standardDeviation * 3) * 2) + 1;
             this.standardDeviation = standardDeviation;
         }
 
@@ -46,44 +65,10 @@
             }
         }
 
-        /// <summary>
-        /// Create a 2 dimensional Gaussian kernel using the Gaussian G(x y) function
-        /// </summary>
-        private void CreateGaussianKernel2D()
-        {
-            int size = this.kernelSize;
-            float[,] kernel = new float[size, size];
-
-            int midpoint = size / 2;
-            float sum = 0;
-            for (int i = 0; i < size; i++)
-            {
-                int x = i - midpoint;
-
-                for (int j = 0; j < size; j++)
-                {
-                    int y = j - midpoint;
-                    float gxy = this.Gaussian2D(x, y);
-                    sum += gxy;
-                    kernel[i, j] = gxy;
-                }
-            }
-
-            // Normalise kernel so that the sum of all weights equals 1
-            //for (int i = 0; i < size; i++)
-            //{
-            //    for (int j = 0; j < size; j++)
-            //    {
-            //        kernel[i, 0] = kernel[i, j] / sum;
-            //    }
-            //}
-
-            this.kernelY = kernel;
-        }
-
         /// <summary>
         /// Create a 1 dimensional Gaussian kernel using the Gaussian G(x) function
         /// </summary>
+        /// <param name="horizontal">Whether to calculate a horizontal kernel.</param>
         /// <returns>The <see cref="T:float[,]"/></returns>
         private float[,] CreateGaussianKernel(bool horizontal)
         {
@@ -91,10 +76,10 @@
             float[,] kernel = horizontal ? new float[1, size] : new float[size, 1];
             float sum = 0.0f;
 
-            int midpoint = size / 2;
+            float midpoint = (size - 1) / 2f;
             for (int i = 0; i < size; i++)
             {
-                int x = i - midpoint;
+                float x = i - midpoint;
                 float gx = this.Gaussian(x);
                 sum += gx;
                 if (horizontal)
@@ -145,27 +130,5 @@
 
             return left * right;
         }
-
-        /// <summary>
-        /// Implementation of 2D Gaussian G(x) function
-        /// </summary>
-        /// <param name="x">The x provided to G(x y)</param>
-        /// <param name="y">The y provided to G(x y)</param>
-        /// <returns>The Gaussian G(x y)</returns>
-        private float Gaussian2D(float x, float y)
-        {
-            const float Numerator = 1.0f;
-            float deviation = this.standardDeviation;
-            double pow = Math.Pow(deviation, 2);
-            float denominator = (float)((2 * Math.PI) * pow);
-
-            float exponentNumerator = (-x * x) + (-y * y);
-            float exponentDenominator = (float)(2 * pow);
-
-            float left = Numerator / denominator;
-            float right = (float)Math.Exp(exponentNumerator / exponentDenominator);
-
-            return left * right;
-        }
     }
 }

src/ImageProcessor/project.lock.json.REMOVED.git-id

@@ -1 +1 @@
-3f05708641eb3ed085d4689aae4a960eb067fd16
+eb00c54ee74016c2b70f81963e7e8f83cb2dd54b

tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs

@@ -6,7 +6,6 @@ namespace ImageProcessor.Tests
     using System.Numerics;
 
     using ImageProcessor.Filters;
-    using ImageProcessor.Filters.Convolution;
 
     using Xunit;
 
@@ -39,7 +38,7 @@ namespace ImageProcessor.Tests
             //{ "RobertsCross", new RobertsCross() },
             //{ "Scharr", new Scharr() },
             //{ "Sobel", new Sobel() },
-            { "GuassianBlur", new GuassianBlur(20) }
+            { "GuassianBlur", new GuassianBlur(5) }
         };
 
         [Theory]

tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs

@@ -22,6 +22,7 @@ namespace ImageProcessor.Tests
             //"../../TestImages/Formats/Jpg/Backdrop.jpg",
             //"../../TestImages/Formats/Jpg/Calliphora.jpg",
             "../../TestImages/Formats/Jpg/ant.jpg",
+            "../../TestImages/Formats/Jpg/parachute.jpg",
             //"../../TestImages/Formats/Jpg/lomo.jpg",
             //"../../TestImages/Formats/Jpg/shaftesbury.jpg",
             //"../../TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg",
@@ -31,6 +32,7 @@ namespace ImageProcessor.Tests
             //"../../TestImages/Formats/Png/gamma-1.0-or-2.2.png",
             //"../../TestImages/Formats/Png/splash.png",
             //"../../TestImages/Formats/Gif/leaf.gif",
+            "../../TestImages/Formats/Gif/ben2.gif",
             //"../../TestImages/Formats/Gif/rings.gif",
             //"../../TestImages/Formats/Gif/ani2.gif",
             //"../../TestImages/Formats/Gif/giphy.gif"

tests/ImageProcessor.Tests/TestImages/Formats/Gif/ben2.gif

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e69e47e78320e848efd07d83e265328a749cafde65291c0d7e7bdba90ba658c3
+size 50960

tests/ImageProcessor.Tests/TestImages/Formats/Jpg/parachute.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:88f4e06fb00ecdcc663a8ba4227dc89be2e3b000bd39246d6bc4adb6450520b3
+size 28324