bandpass_image — Edge extraction using bandpass filters.
bandpass_image serves as an edge filter. It applies a linear filter with the following convolution mask to Image:
FilterType: 'lines' In contrast to the edge operator sobel_amp this filter detects lines instead of edges, i.e., two closely adjacent edges.
0 -2 -2 -2 0 -2 0 3 0 -2 -2 3 12 3 -2 -2 0 3 0 -2 0 -2 -2 -2 0
At the border of the image the gray values are mirrored. Over- and underflows of gray values are clipped. The resulting images are returned in ImageBandpass.
Note that filter operators may return unexpected results if an image with a reduced domain is used as input. Please refer to the chapter Filters.
Filter type: currently only 'lines' is supported.
Default value: 'lines'
List of values: 'lines'
bandpass_image(Image,&LineImage,"lines"); threshold(LineImage,&Lines,60.0,255.0); skeleton(Lines,&ThinLines);
bandpass_image returns 2 (H_MSG_TRUE) if all parameters are correct. If the input is empty the behaviour can be set via set_system(::'no_object_result',<Result>:). If necessary, an exception is raised.
convol_image, topographic_sketch, texture_laws