bandpass_image

Herror ::bandpass_image ( Hobject Image, Hobject *ImageBandpass, const HTuple &FilterType ) HImage HImage::BandpassImage ( const HTuple &FilterType ) const HImageArray HImageArray::BandpassImage ( const HTuple &FilterType ) const

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 to the interval [0,255]. The resulting images are returned in ImageBandpass.

Parameters

`Image` (input_object)	(multichannel-)image(-array) `->` Hobject: HImage(Array) ( byte )
Input images.

`ImageBandpass` (output_object)	(multichannel-)image(-array) `->` Hobject : HImage(Array)* ( byte )
Bandpass-filtered images.

`FilterType` (input_control)	string `->` HTuple.char *
Filter type: currently only 'lines' is supported.
Default value: 'lines'
List of values: 'lines'

Example

bandpass_image(Image,&LineImage,"lines");
threshold(LineImage,&Lines,60.0,255.0);
skeleton(Lines,&ThinLines);

Result

::bandpass_image returns 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 handling is raised.

Possible Successors

::threshold, ::skeleton

Alternatives

::convol_image, ::topographic_sketch, ::texture_laws

See also

::highpass_image, ::gray_skeleton

Module

Image filters