/// <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));
}
private void applyButton_Click(object sender, EventArgs e)
{
if (this._inputImage == null)
{
return;
}
this._outputImage?.Dispose();
this._outputImage = new Bitmap(this._inputImage.Size.Width, this._inputImage.Size.Height);
var image = new Color[this._inputImage.Size.Width, this._inputImage.Size.Height];
var image2 = new Color[this._inputImage2.Size.Width, this._inputImage2.Size.Height];
// Setup progress bar
this.progressBar.Visible = true;
this.progressBar.Minimum = 1;
this.progressBar.Maximum = this._inputImage.Size.Width * this._inputImage.Size.Height;
this.progressBar.Value = 1;
this.progressBar.Step = 1;
// Copy input Bitmap to array
for (var x = 0; x < this._inputImage.Size.Width; x++)
{
for (var y = 0; y < this._inputImage.Size.Height; y++)
{
image[x, y] = this._inputImage.GetPixel(x, y); // Set pixel color in array at (x,y)
}
}
// Copy input Bitmap to array for the control image
for (var x = 0; x < this._inputImage2.Size.Width; x++)
{
for (var y = 0; y < this._inputImage2.Size.Height; y++)
{
image2[x, y] = this._inputImage2.GetPixel(x, y); // Set pixel color in array at (x,y)
}
}
//==================================================================================
//================================= PIPELINE =======================================
//==================================================================================
//RESET VARS FROM PREVIOUS IMAGE:
FloodFill.ObjectCount = 0;
FloodFill.Objects = new List <PictureObject>();
//===================== Preprocessing: Filtering, Segmentation =====================
var greyscale = HelperFunctions.Greyscalize(image);
HelperFunctions.GlobalMask = HelperFunctions.Greyscalize(image2);
//===================== Edge Detection =============================================
var detectSides = CannyEdge.CannyEdgeDetector(greyscale, 1, GlobalThreshold.OtsuThreshold(greyscale));
//===================== Find sides of road poles using Hough transform =============
var lines = HoughTransform.FoundLines(detectSides, 0, 0);
var cartLines = HoughExtensions.GetAllCartesianLines(lines, detectSides);
var pairs = HoughExtensions.GetPairs(cartLines, detectSides.GetLength(1));
var roughPairs = HoughExtensions.GetRoughPairs(cartLines, detectSides.GetLength(1));
//===================== Find lower and upper boundaries of poles ===================
var workingImage = BilateralFilter.BilateralFilter2D(greyscale);
workingImage = EdgeDetection.DetectEdges(HelperFunctions.Threshold(workingImage, GlobalThreshold.OtsuThreshold(workingImage)));
detectSides = HoughExtensions.CleanOutsidePairs(workingImage, roughPairs);
detectSides = FloodFill.MarkObjects(detectSides);
detectSides = FloodFill.filterObjects(detectSides);
//==================================================================================
//==================================================================================
//==================================================================================
var nDV = ValueCounter(detectSides);
this.label2.Text = "Number of distinct values: " + nDV;
Console.ForegroundColor = ConsoleColor.Magenta;
Console.WriteLine("[Done] Final image with size " + detectSides.GetLength(0) + "x" + detectSides.GetLength(1) + " and " + nDV + " distinct Values");
Console.ResetColor();
var newImage = Colorize(detectSides);
DrawBoundingBox(newImage);
var outputResized = new Bitmap(this._outputImage, detectSides.GetLength(0), detectSides.GetLength(1));
// Copy array to output Bitmap
for (var x = 0; x < newImage.GetLength(0); x++)
{
for (var y = 0; y < newImage.GetLength(1); y++)
{
outputResized.SetPixel(x, y, newImage[x, y]); // Set the pixel color at coordinate (x,y)
}
}
var g = Graphics.FromImage(outputResized);
DrawPairs(pairs, outputResized); // Draw pairs generated by hough transform
FloodFill.DrawFinal(this._inputImage, pairs);
pictureBox2.Image = this._inputImage; // Display output image - replace InputImage with OutputResized to see hough pairs and object map with bounding boxes
progressBar.Visible = true; // Hide progress bar
}
