- image
matrix or 3-dimensional array and the third dimension must be equal to 3
- method
the method should be one of 'Frei_chen', 'LoG' (Laplacian of Gaussian), 'Prewitt', 'Roberts_cross', 'Scharr', 'Sobel'
- conv_mode
the convolution mode should be one of 'same', 'full'
- approx
if TRUE, approximate calculation of gradient (applies to all filters except for 'LoG')
- gaussian_dims
integer specifying the horizontal and vertical dimensions of the gaussian filter
- sigma
float parameter sigma for the gaussian filter
- range_gauss
float number specifying the range of values for the gaussian filter
- laplacian_type
integer value specifying the type for the laplacian kernel (one of 1, 2, 3, 4)