robertsrobertsrobertsRobertsRoberts (Operator)

Name

robertsrobertsrobertsRobertsRoberts — Detect edges using the Roberts filter.

Signature

Description

robertsrobertsrobertsRobertsRoberts calculates the first derivative of an image and is used as an edge operator. If the following mask describes a part of the image,

                        A               B

                        C               D

the different filter types are defined as follows:

   'roberts_max'     max(| A - D |,| B - C |)
   'gradient_max'    max(| A + B - (C + D)|,| A + C - (B + D)|)
   'gradient_sum'    |A + B - (C + D)| + |A + C - (B + D)|

If an overflow occurs the result is clipped. The result of the operator is stored at the pixel with the coordinates of "D".

Parallelization

• 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')
roberts(Image,Roberts,'roberts_max')
threshold(Roberts,Margin,128,255)

read_image(&Image,"fabrik");
roberts(Image,&Roberts,"roberts_max");
threshold(Roberts,&Margin,128.0,255.0);

read_image(Image,'fabrik')
roberts(Image,Roberts,'roberts_max')
threshold(Roberts,Margin,128,255)

read_image(Image,'fabrik')
roberts(Image,Roberts,'roberts_max')
threshold(Roberts,Margin,128,255)

read_image(Image,'fabrik')
roberts(Image,Roberts,'roberts_max')
threshold(Roberts,Margin,128,255)

Result

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

Possible Predecessors

binomial_filterbinomial_filterbinomial_filterBinomialFilterBinomialFilter, gauss_imagegauss_imagegauss_imageGaussImageGaussImage

Possible Successors

thresholdthresholdthresholdThresholdThreshold, skeletonskeletonskeletonSkeletonSkeleton

Alternatives

edges_imageedges_imageedges_imageEdgesImageEdgesImage, sobel_ampsobel_ampsobel_ampSobelAmpSobelAmp, frei_ampfrei_ampfrei_ampFreiAmpFreiAmp, kirsch_ampkirsch_ampkirsch_ampKirschAmpKirschAmp, prewitt_ampprewitt_ampprewitt_ampPrewittAmpPrewittAmp

See also

laplacelaplacelaplaceLaplaceLaplace, highpass_imagehighpass_imagehighpass_imageHighpassImageHighpassImage, bandpass_imagebandpass_imagebandpass_imageBandpassImageBandpassImage

Module

Foundation