The operator shock_filtershock_filterShockFiltershock_filterShockFilterShockFilter applies a shock filter to the
input image ImageImageImageImageImageimage to sharpen the edges contained in it.
The principle of the shock filter is based on the transport of the
gray values of the image towards an edge from both sides through
dilation and erosion and satisfies the differential equation
The decision between dilation and erosion is made using the sign
function s with values {-1,0,+1} on a
conventional edge detector. The detector of Canny
is available with ModeModeModeModeModemode='canny'"canny""canny""canny""canny""canny" and the detector
of Marr/Hildreth (the Laplace operator)
can be selected by ModeModeModeModeModemode='laplace'"laplace""laplace""laplace""laplace""laplace".
To make the edge detection more robust, in particular on noisy
images, it can be performed on a smoothed image matrix. This is done
by giving the standard deviation of a Gaussian kernel for
convolution with the image matrix in the parameter SigmaSigmaSigmaSigmaSigmasigma.
F. Guichard, J. Morel; “A Note on Two Classical Shock Filters and
Their Asymptotics”; Michael Kerckhove (Ed.): Scale-Space and
Morphology in Computer Vision, LNCS 2106, pp. 75-84; Springer, New
York; 2001.
G. Aubert, P. Kornprobst; “Mathematical Problems in Image
Processing”; Applied Mathematical Sciences 147; Springer, New
York; 2002.