/// <summary>
/// CONSTRUCTOR
/// Pass both the original image and structure tensor because need to calculate derivatives as well as eigenvalues.
/// Cannot easily derive the partial derivatives from the structure tensor because have lost the sign info.
/// </summary>
/// <param name="avImage"></param>
/// <param name="avStructureTensor"></param>
public static StructureTensorResult GetStructureTensorInfo(double[,] avImage, double[,] avStructureTensor)
{
int rowCount = avStructureTensor.GetLength(0);
int colCount = avStructureTensor.GetLength(1);
if (rowCount != 2 && colCount != 2)
{
throw new Exception("Structure tensor must be 2x2 matrix");
}
double dx = avImage[1, 1] - avImage[1, 0];
double dy = avImage[0, 0] - avImage[1, 0];
var result = new StructureTensorResult();
result.Derivative = dy / dx;
result.Magnitude = Math.Sqrt((dy * dy) + (dx * dx));
double radians = Math.Atan2(dy, dx);
result.Radians = radians;
result.Degrees = radians * (180 / Math.PI);
double[] eigenValues = CalculateEigenValues(avStructureTensor);
result.EigenValue1 = Math.Abs(eigenValues[0]);
result.EigenValue2 = Math.Abs(eigenValues[1]);
result.Dominance = Math.Abs((result.EigenValue1 - result.EigenValue2) / (result.EigenValue1 + result.EigenValue2));
//Console.WriteLine("Slope magnitude={0} dy/dx={1}", result.Magnitude, result.Derivative);
//Console.WriteLine("Radians={0:f2} Angle={1:f1}", radians, result.Degrees);
//Console.WriteLine("Eigenvalues = {0:f6} and {1:f6}. Dominance = {2:f2}", eigenValues[0], eigenValues[1], result.Dominance);
return(result);
}
public static void Test1StructureTensor()
{
// create a local image matrix
double[,] image =
{
{
0.9, 10.0,
},
{
10.0, 0.0,
},
};
var structureTensorMatrix = CalculateStructureTensor(image);
StructureTensorResult result = GetStructureTensorInfo(image, structureTensorMatrix);
}
