public void ExtractAnchors(string sourceFileName,
GradientOperator gradientOperator, int gradientThreshold,
int anchorScanInterval, int anchorThreshold)
{
// Arrange
var source = LoadImage(sourceFileName);
var rows = source.Size.Height;
var columns = source.Size.Width;
var gradients = new Gradients(rows, columns);
gradients.ComputeGradient(source, gradientOperator, gradientThreshold);
// Act
var anchors = gradients.ExtractAnchors(anchorScanInterval, anchorThreshold);
// Assert
var anchorMap = new Mat(rows, columns, Depth.U8, 1);
anchorMap.Set(Scalar.All(0));
foreach (var anchor in anchors)
{
anchorMap.SetReal(anchor.Y, anchor.X, 255);
}
var resultFileName = Path.Combine("Output", "ExtractAnchors", $"{Path.GetFileNameWithoutExtension(sourceFileName)}_{gradientOperator}_{gradientThreshold}_{anchorScanInterval}_{anchorThreshold}.png");
SaveImage(anchorMap, resultFileName);
}
public void DrawEdges(Arr source, Arr destination, GradientOperator gradientOperator, int gradientThreshold, int anchorScanInterval, int anchorThreshold)
{
// compute the gradient and direction maps
_gradients.ComputeGradient(source, gradientOperator, gradientThreshold);
// compute the anchors
var anchors = _gradients.ExtractAnchors(anchorScanInterval, anchorThreshold);
// connect the anchors by smart routing
foreach (var anchor in anchors)
{
DrawEdge(anchor.Y, anchor.X, _gradients.GradientMap, _gradients.DirectionMap, destination, _rows, _columns);
}
}
public void ComputeGradient(Arr source, GradientOperator gradientOperator, double gradientThreshold)
{
// gaussian filtering
CV.Smooth(source, _smoothed, SmoothMethod.Gaussian, 5, 5, 1.0);
// calculate gradients
switch (gradientOperator)
{
case GradientOperator.Prewitt:
CV.Filter2D(_smoothed, _gradientX, PrewittX);
CV.Filter2D(_smoothed, _gradientY, PrewittY);
if (gradientThreshold < 0.0)
{
gradientThreshold = 6.0;
}
break;
case GradientOperator.Sobel:
CV.Sobel(_smoothed, _gradientX, 1, 0);
CV.Sobel(_smoothed, _gradientY, 0, 1);
break;
case GradientOperator.Scharr:
CV.Sobel(_smoothed, _gradientX, 1, 0, -1);
CV.Sobel(_smoothed, _gradientY, 0, 1, -1);
break;
default:
throw new Exception($"Unknown gradient operator: {gradientOperator}");
}
// calculate absolute values for gradients
CV.ConvertScaleAbs(_gradientX, _absGradientX);
CV.ConvertScaleAbs(_gradientY, _absGradientY);
// merge gradients
// d = 0.5 * abs(dx) + 0.5 * abs(dy)
CV.AddWeighted(_absGradientX, 0.5, _absGradientY, 0.5, 0.0, GradientMap);
// eliminate gradient weak pixels
CV.Threshold(GradientMap, GradientMap, gradientThreshold, 255, ThresholdTypes.ToZero);
// edge direction
// abs(dx) >= abs(dy) => VERTICAL
CV.Cmp(_absGradientX, _absGradientY, DirectionMap, ComparisonOperation.GreaterOrEqual);
}
public void ComputeGradient(string sourceFileName, GradientOperator gradientOperator, int gradientThreshold)
{
// Arrange
var source = LoadImage(sourceFileName);
var rows = source.Size.Height;
var columns = source.Size.Width;
var gradients = new Gradients(rows, columns);
// Act
gradients.ComputeGradient(source, gradientOperator, gradientThreshold);
// Assert
var gradientFileName = Path.Combine("Output", "ComputeGradient", $"{Path.GetFileNameWithoutExtension(sourceFileName)}_{gradientOperator}_{gradientThreshold}_GradientMap.png");
var directionsFileName = Path.Combine("Output", "ComputeGradient", $"{Path.GetFileNameWithoutExtension(sourceFileName)}_{gradientOperator}_{gradientThreshold}_DirectionsMap.png");
SaveImage(gradients.GradientMap, gradientFileName);
SaveImage(gradients.DirectionMap, directionsFileName);
}
public Edges DrawEdgesParameterFree(Arr source, GradientOperator gradientOperator, int gradientThreshold, int anchorScanInterval, int minLength = 0)
{
// compute the gradient and direction maps
_gradients.ComputeGradient(source, gradientOperator, gradientThreshold);
// compute the normalized cummulative histogram
_gradients.CummulativeHistogram();
// compute the anchors
var anchors = _gradients.ExtractAnchors(anchorScanInterval);
// connect the anchors by smart routing
var edges = new Edges();
foreach (var anchor in anchors)
{
DrawEdge(anchor.Y, anchor.X, _gradients, _edgesMap, edges, _rows, _columns, minLength);
}
return(edges);
}
public void DrawEdges(
string sourceFileName,
GradientOperator gradientOperator, int gradientThreshold,
int anchorScanInterval, int anchorThreshold)
{
// Arrange
var source = LoadImage(sourceFileName);
var rows = source.Size.Height;
var columns = source.Size.Width;
var edgeDrawing = new EdgeDrawing(rows, columns);
var edgesMap = new Mat(rows, columns, Depth.U8, 1);
edgesMap.Set(Scalar.All(0));
// Act
edgeDrawing.DrawEdges(source, edgesMap, gradientOperator, gradientThreshold, anchorScanInterval, anchorThreshold);
// Assert
var resultFileName = Path.Combine("Output", "DrawEdges", $"{Path.GetFileNameWithoutExtension(sourceFileName)}_{gradientOperator}_{gradientThreshold}_{anchorScanInterval}_{anchorThreshold}_EdgesMap.png");
SaveImage(edgesMap, resultFileName);
}
public Edges DrawEdges(Arr source, GradientOperator gradientOperator, int gradientThreshold, int anchorScanInterval, int anchorThreshold, int minLength = 0)
{
// compute the gradient and direction maps
_gradients.ComputeGradient(source, gradientOperator, gradientThreshold);
// compute the anchors
var anchors = _gradients.ExtractAnchors(anchorScanInterval, anchorThreshold);
// initialize the edges map
if (_edgesMap is null)
{
_edgesMap = new Mat(_rows, _columns, Depth.U8, 1);
}
_edgesMap.Set(Scalar.All(0));
// connect the anchors by smart routing
var edges = new Edges();
foreach (var anchor in anchors)
{
DrawEdge(anchor.Y, anchor.X, _gradients, _edgesMap, edges, _rows, _columns, minLength);
}
return(edges);
}
public static MyFilter GradientKernel(GradientOperator operate, GradientDirect direct)
{// please not use MyFilter.GradientDirect.BOTH
MyFilter kernel = null;
switch (operate)
{
case MyFilter.GradientOperator.SOBEL:
kernel = new MyFilter(3);
switch (direct)
{
case MyFilter.GradientDirect.X:
if (_SOBEL_X == null)
{
kernel[0, 0] = 1;
kernel[2, 0] = -1;
kernel[0, 1] = 2;
kernel[2, 1] = -2;
kernel[0, 2] = 1;
kernel[2, 2] = -1;
_SOBEL_X = kernel;
return(kernel);
}
else
{
return(_SOBEL_X);
}
case MyFilter.GradientDirect.Y:
if (_SOBEL_Y == null)
{
kernel[0, 0] = 1;
kernel[1, 0] = 2;
kernel[2, 0] = 1;
kernel[0, 2] = -1;
kernel[1, 2] = -2;
kernel[2, 2] = -1;
_SOBEL_Y = kernel;
return(kernel);
}
else
{
return(_SOBEL_Y);
}
}
break;
case MyFilter.GradientOperator.PREWITT:
kernel = new MyFilter(3);
switch (direct)
{
case MyFilter.GradientDirect.X:
if (_PREWITT_X == null)
{
kernel[0, 0] = 1;
kernel[2, 0] = -1;
kernel[0, 1] = 1;
kernel[2, 1] = -1;
kernel[0, 2] = 1;
kernel[2, 2] = -1;
_PREWITT_X = kernel;
return(kernel);
}
else
{
return(_PREWITT_X);
}
case MyFilter.GradientDirect.Y:
if (_PREWITT_Y == null)
{
kernel[0, 0] = 1;
kernel[1, 0] = 1;
kernel[2, 0] = 1;
kernel[0, 2] = -1;
kernel[1, 2] = -1;
kernel[2, 2] = -1;
_PREWITT_Y = kernel;
return(kernel);
}
else
{
return(_PREWITT_Y);
}
}
break;
case MyFilter.GradientOperator.ROBERT:
kernel = new MyFilter(2);
switch (direct)
{
case MyFilter.GradientDirect.X:
if (_ROBERT_X == null)
{
kernel[0, 0] = -1;
kernel[1, 0] = 0;
kernel[0, 1] = 0;
kernel[1, 1] = 1;
_ROBERT_X = kernel;
return(kernel);
}
else
{
return(_ROBERT_X);
}
case MyFilter.GradientDirect.Y:
if (_ROBERT_Y == null)
{
kernel[0, 0] = 0;
kernel[1, 0] = -1;
kernel[0, 1] = 1;
kernel[1, 1] = 0;
_ROBERT_Y = kernel;
return(kernel);
}
else
{
return(_ROBERT_Y);
}
}
break;
}
return(kernel);
}
