robinson_dirrobinson_dirRobinsonDirRobinsonDir (Operator)

Name

robinson_dirrobinson_dirRobinsonDirRobinsonDir — Detect edges (amplitude and direction) using the Robinson operator.

Signature

Description

robinson_dirrobinson_dirRobinsonDirRobinsonDirRobinsonDir calculates an approximation of the first derivative of the image data and is used as an edge detector. In robinson_amprobinson_ampRobinsonAmpRobinsonAmpRobinsonAmp the following four of the originally proposed eight 3x3 filter masks are convolved with the image. The other four masks are obtained by a multiplication by -1. All masks contain only the values 0,1,-1,2,-2. -1 0 1 2 1 0 -2 0 2 1 0 -1 -1 0 1 0 -1 -2 0 1 2 1 2 1 -1 0 1 0 0 0 -2 -1 0 -1 -2 -1 The result image contains the maximum response of all masks. The edge directions are returned in ImageEdgeDirImageEdgeDirImageEdgeDirImageEdgeDirimageEdgeDir, and are stored as x / 2. They correspond to the direction of the mask yielding the maximum response.

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')
robinson_dir(Image,Robinson_dirA,Robinson_dirD)
threshold(Robinson_dirA,Res,128,255)

read_image(&Image,"fabrik");
robinson_dir(Image,&Robinson_dirA,&Robinson_dirD);
threshold(Robinson_dirA,&Res,128,255);

read_image(Image,'fabrik')
robinson_dir(Image,Robinson_dirA,Robinson_dirD)
threshold(Robinson_dirA,Res,128,255)

read_image(Image,'fabrik')
robinson_dir(Image,Robinson_dirA,Robinson_dirD)
threshold(Robinson_dirA,Res,128,255)

read_image(Image,'fabrik')
robinson_dir(Image,Robinson_dirA,Robinson_dirD)
threshold(Robinson_dirA,Res,128,255)

Result

robinson_dirrobinson_dirRobinsonDirRobinsonDirRobinsonDir 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>)SetSystem("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

binomial_filterbinomial_filterBinomialFilterBinomialFilterBinomialFilter, gauss_filtergauss_filterGaussFilterGaussFilterGaussFilter, sigma_imagesigma_imageSigmaImageSigmaImageSigmaImage, median_imagemedian_imageMedianImageMedianImageMedianImage, smooth_imagesmooth_imageSmoothImageSmoothImageSmoothImage

Possible Successors

hysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThresholdHysteresisThreshold, thresholdthresholdThresholdThresholdThreshold, gray_skeletongray_skeletonGraySkeletonGraySkeletonGraySkeleton, nonmax_suppression_dirnonmax_suppression_dirNonmaxSuppressionDirNonmaxSuppressionDirNonmaxSuppressionDir, close_edgesclose_edgesCloseEdgesCloseEdgesCloseEdges, close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthCloseEdgesLength

Alternatives

edges_imageedges_imageEdgesImageEdgesImageEdgesImage, sobel_dirsobel_dirSobelDirSobelDirSobelDir, kirsch_dirkirsch_dirKirschDirKirschDirKirschDir, prewitt_dirprewitt_dirPrewittDirPrewittDirPrewittDir, frei_dirfrei_dirFreiDirFreiDirFreiDir

See also

bandpass_imagebandpass_imageBandpassImageBandpassImageBandpassImage, laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss

Module

Foundation