public static byte[,] Sharpen(byte[,] input, int w)
{
var imageToSharpen = Convolution.Convolve(input, Laplacian3X3, 1);
var image = new byte[imageToSharpen.GetLength(0), imageToSharpen.GetLength(1)];
for (var x = 0; x < imageToSharpen.GetLength(0); x++)
{
for (var y = 0; y < imageToSharpen.GetLength(1); y++)
{
image[x, y] = (byte)Math.Round(HelperFunctions.ImageClamp(input[x, y] - w * imageToSharpen[x, y]));
}
}
return(image);
}
/// <summary>
/// Edge detection using 4 Sobel kernels
/// </summary>
public static byte[,] DetectEdges(byte[,] input)
{
Console.WriteLine("[Pre-processing] Applying Edge Detection using 4 Sobel kernels...");
var image1 = Convolution.Convolve(input, SobelKernel3X3V, 1);
var image2 = Convolution.Convolve(input, SobelKernel3X3H, 1);
var midImage1 = new byte[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage1.GetLength(0); x++)
{
for (var y = 0; y < midImage1.GetLength(1); y++)
{
var final = Math.Sqrt(image1[x, y] * image1[x, y] + image2[x, y] * image2[x, y]);
midImage1[x, y] = (byte)ImageClamp2(Math.Round(final));
}
}
var image3 = Convolution.Convolve(input, SobelKernel3X3Minv, 1);
var image4 = Convolution.Convolve(input, SobelKernel3X3Minh, 1);
var midImage2 = new byte[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage2.GetLength(0); x++)
{
for (var y = 0; y < midImage2.GetLength(1); y++)
{
var final = Math.Sqrt(image3[x, y] * image3[x, y] + image4[x, y] * image4[x, y]);
midImage2[x, y] = (byte)ImageClamp2(Math.Round(final));
}
}
var finalImage = new byte[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage2.GetLength(0); x++)
{
for (var y = 0; y < midImage2.GetLength(1); y++)
{
var final = Math.Sqrt(midImage1[x, y] * midImage1[x, y] + midImage2[x, y] * midImage2[x, y]);
finalImage[x, y] = (byte)ImageClamp2(Math.Round(final));
}
}
return(finalImage);
}
/// <summary>
/// Perform Canny edge detection
/// </summary>
public static byte[,] CannyEdgeDetector(byte[,] input, int blur = 1, byte high = 90, byte low = 90)
{
var copy = BilateralFilter.BilateralFilter2D(input); // Preprocessing before detecting edges
// ======================= Adapted Sobel edge detection from earlier implementation =======================
var image1 = Convolution.Convolve(copy, EdgeDetection.SobelKernel3X3V, 1);
var image2 = Convolution.Convolve(copy, EdgeDetection.SobelKernel3X3H, 1);
var midImage1 = new double[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage1.GetLength(0); x++)
{
for (var y = 0; y < midImage1.GetLength(1); y++)
{
var final = Math.Sqrt(image1[x, y] * image1[x, y] + image2[x, y] * image2[x, y]);
midImage1[x, y] = (byte)EdgeDetection.ImageClamp2(Math.Round(final));
}
}
var image3 = Convolution.Convolve(copy, EdgeDetection.SobelKernel3X3Minv, 1);
var image4 = Convolution.Convolve(copy, EdgeDetection.SobelKernel3X3Minh, 1);
var midImage2 = new double[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage2.GetLength(0); x++)
{
for (var y = 0; y < midImage2.GetLength(1); y++)
{
var final = Math.Sqrt(image3[x, y] * image3[x, y] + image4[x, y] * image4[x, y]);
midImage2[x, y] = (byte)EdgeDetection.ImageClamp2(Math.Round(final));
}
}
var imageG = new double[image1.GetLength(0), image1.GetLength(1)];
for (var x = 0; x < midImage2.GetLength(0); x++)
{
for (var y = 0; y < midImage2.GetLength(1); y++)
{
var final = midImage1[x, y] + midImage2[x, y];/*Math.Sqrt(midImage1[x, y] * midImage1[x, y] + midImage2[x, y] * midImage2[x, y]);*/
imageG[x, y] = (byte)EdgeDetection.ImageClamp2(Math.Round(final));
}
}
var imageT = new int[midImage1.GetLength(0), midImage1.GetLength(1)];
for (var x = 0; x < imageT.GetLength(0); x++)
{
for (var y = 0; y < imageT.GetLength(1); y++)
{
imageT[x, y] = (int)Math.Round(Math.Atan2(midImage2[x, y], midImage2[x, y]) * (5.0 / Math.PI) + 5) % 5;
}
}
// ========================================================================================================
var suppressed = Suppress(imageG, imageT); //Perform Non-maximum suppression
var highEdges = HelperFunctions.ThresholdDouble(suppressed, high); // Keep the strong edges in one map
var lowEdges = HelperFunctions.ThresholdDouble(suppressed, low); // Keep weaker edges in another map
var highEdgesByte = Double2DtoByte2D(highEdges);
var lowEdgesByte = Double2DtoByte2D(lowEdges);
var CombinedThresholds = BinaryOperators.ORoperator(highEdgesByte, lowEdgesByte);
// Hysteresis to trace edges
return(Hysteresis(highEdgesByte, CombinedThresholds));
}