gen_filter_mask ( : ImageFilter : FileName, Scale, Size : )

Store a filter mask in the spatial domain as a real-image.

gen_filter_mask stores a filter mask in the spatial domain as a real-image. The center of the filter mask lies in the center of the resulting image. The parameter Scale determines by which amount the values of the filter mask are multiplied (this results in larger values of the Fourier transform of the filter). The file format of the filter mask file is described with the operator convol__. Example filter masks can be found in the directory ``filter'' in the HORUS home directory. This operator is useful for visualizing the frequency response of filter masks (by applying a Fourier transform to the result image of this operator).


Parameters

ImageFilter (output_object)
image(-array) -> object : real
Filter in the spatial domain.

FileName (input_control)
string -> string
File name of the filter mask.
Default value: 'sobel'
Suggested values: 'laplace4', 'laplace8', 'lowpass_3_3'

Scale (input_control)
real -> real
Scaling factor.
Default value: 1.0
Suggested values: 0.3, 0.5, 0.75, 1.0, 1.25, 1.5, 2.0
Range of values: 0.001 <= Scale <= 10.0
Minimum increment: 0.001
Recommended increment: 0.1
Restriction: Scale > 0.0

Size (input_control)
integer -> integer
Size (dimension) of the image (filter).
Default value: 512
List of values: 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192


Example
gen_filter_mask(&Filter,"lowpass_3_3",1.0,512);
fft__(Filter,&FilterFFT);
set_paint("3D-plot_hidden");
disp_image(FilterFFT);

Possible Successors

fft__, fft_generic


See also

convol__



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