prewitt_ampprewitt_ampPrewittAmpPrewittAmpprewitt_amp (Operator)

Name

prewitt_ampprewitt_ampPrewittAmpPrewittAmpprewitt_amp — Detect edges (amplitude) using the Prewitt operator.

Signature

Description

prewitt_ampprewitt_ampPrewittAmpPrewittAmpprewitt_amp calculates an approximation of the first derivative of the image data and is used as an edge detector. The filter is based on the following filter masks: A = 1 1 1 0 0 0 -1 -1 -1 B = 1 0 -1 1 0 -1 1 0 -1 The result image contains the maximum response of the masks A and B.

Attention

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.

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Automatically parallelized on tuple level.
• Automatically parallelized on channel level.
• Automatically parallelized on domain level.

Parameters

read_image(Image,'fabrik')
prewitt_amp(Image,Prewitt)
threshold(Prewitt,Edges,128,255)

read_image(&Image,"fabrik");
prewitt_amp(Image,&Prewitt);
threshold(Prewitt,&Edges,128,255);

read_image(Image,'fabrik')
prewitt_amp(Image,Prewitt)
threshold(Prewitt,Edges,128,255)

read_image(Image,'fabrik')
prewitt_amp(Image,Prewitt)
threshold(Prewitt,Edges,128,255)

Result

prewitt_ampprewitt_ampPrewittAmpPrewittAmpprewitt_amp always returns 2 ( H_MSG_TRUE) . If the input is empty the behavior can be set via set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

binomial_filterbinomial_filterBinomialFilterBinomialFilterbinomial_filter, gauss_filtergauss_filterGaussFilterGaussFiltergauss_filter, sigma_imagesigma_imageSigmaImageSigmaImagesigma_image, median_imagemedian_imageMedianImageMedianImagemedian_image, smooth_imagesmooth_imageSmoothImageSmoothImagesmooth_image

Possible Successors

thresholdthresholdThresholdThresholdthreshold, gray_skeletongray_skeletonGraySkeletonGraySkeletongray_skeleton, nonmax_suppression_ampnonmax_suppression_ampNonmaxSuppressionAmpNonmaxSuppressionAmpnonmax_suppression_amp, close_edgesclose_edgesCloseEdgesCloseEdgesclose_edges, close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthclose_edges_length

Alternatives

sobel_ampsobel_ampSobelAmpSobelAmpsobel_amp, kirsch_ampkirsch_ampKirschAmpKirschAmpkirsch_amp, frei_ampfrei_ampFreiAmpFreiAmpfrei_amp, robinson_amprobinson_ampRobinsonAmpRobinsonAmprobinson_amp, robertsrobertsRobertsRobertsroberts

See also

bandpass_imagebandpass_imageBandpassImageBandpassImagebandpass_image, laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGausslaplace_of_gauss

Module

Foundation