For a better rotation invariance, the Scharr operator should be used.The Sobel operator has a better rotation invariance than the Prewitt operator, but a worse rotation invariance than the Scharr operator.References Notes Take the square root of the sum of the squares of the horizontal and vertical Sobels to get a magnitude that’s somewhat insensitive to direction.
They are especially suitable for edge detection and texture classification. Return real and imaginary responses to Gabor filter.
They are especially suitable for edge detection and texture classification. Gabor kernel is a Gaussian kernel modulated by a complex harmonic function.
The real and imaginary parts of the Gabor filter kernel are applied to the image and the response is returned as a pair of arrays.
Gabor filter is a linear filter with a Gaussian kernel which is modulated by a sinusoidal plane wave.
k is a configurable parameter that weights the effect of standard deviation. k is a configurable parameter that weights the effect of standard deviation.
R is the maximum standard deviation of a greyscale image.
Notes Return the square root of the sum of squares of the horizontal and vertical Prewitt transforms.
The edge magnitude depends slightly on edge directions, since the approximation of the gradient operator by the Prewitt operator is not completely rotation invariant.
As an approximation of the gradient, the Sobel operator is not completely rotation-invariant.
The Scharr operator should be used for a better rotation invariance.
Calculates the eigenvectors of the Hessian to compute the similarity of an image region to vessels, according to the method described in _.