Synopsis

HxImageRep HxGaussDerivative2d (HxImageRep img, double sigma, int orderDerivx, int orderDerivy, double truncation = 3.0)

Input

HxImageRep img

The image you want to convolve with a Gaussian kernel. The used Gaussian kernel is composed from two seperate kernels, one for the x-direction and one for the y-direction.

double sigma

The sigma of the Gaussian kernel in both directions.

int orderDerivx

The order of the derivative of the Gaussian kernel in the x-direction.

int orderDerivy

The order of the derivative of the Gaussian kernel in the y-direction.

double truncation

This parameter determines at how many sigma the Gaussian filter is clipped in both directions.

Return value

HxImageRep

The result of convolving the input image with a Gaussian kernel as described by the parameters sigma, orderDerivx, orderDerivy and trunction.

Description

The function HxGaussDerivative2d convolves 2D-images with a Gaussian filter funtion. The filter function is separated in the x- and y-direction, where the order of the derivative in both directions can be given seperately. The truncation (in both directions) determines the size of the filter in sigma (of the particular direction), where the filter size, in sigma, is 2 times the truncation plus 1. Sigma is equal for both directions and is given by `sigma'. For vector images, each channel is convolved separately with the Gaussian kernel.

Remarks

Valid image types

All 2D types of images are allowed for this function.

Valid values for the parameters

sigma and truncation should both be greater than zero. orderDerivx and orderDerivy should be larger or equal to zero.

Border handling

This function uses MIRRORED border handling, see the section on Border handling.

See also

HxGauss, HxConvGauss2d, HxGaussDerivative3d,

Keywords

Filter, Convolution, Gauss, Gaussian derivative,

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