prewitt_ampPrewittAmpPrewittAmpprewitt_ampprewitt_amp🔗

Short description🔗

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

Signature🔗

prewitt_amp( image Image, out image ImageEdgeAmp )

HImage HImage::PrewittAmp( ) const

HImage HImage.PrewittAmp( )

Description🔗

prewitt_ampPrewittAmp 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🔗

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🔗

Imageimageimage (input_object) (multichannel-)image(-array) → object (byte / int2 / uint2)HObject (byte / int2 / uint2)HImage (byte / int2 / uint2)HObject (byte / int2 / uint2)Hobject (byte / int2 / uint2)

Input image.

ImageEdgeAmpimageEdgeAmpimage_edge_amp (output_object) (multichannel-)image(-array) → object (byte / int2 / uint2)HObject (byte / int2 / uint2)HImage (byte / int2 / uint2)HObject (byte / int2 / uint2)Hobject * (byte / int2 / uint2)

Edge amplitude (gradient magnitude) image.

Example🔗

(HDevelop)

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

(C)

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

Result🔗

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

Combinations with other operators🔗

Combinations

Possible predecessors

binomial_filterBinomialFilter, gauss_filterGaussFilter, sigma_imageSigmaImage, median_imageMedianImage, smooth_imageSmoothImage

Possible successors

thresholdThreshold, gray_skeletonGraySkeleton, nonmax_suppression_ampNonmaxSuppressionAmp, close_edgesCloseEdges, close_edges_lengthCloseEdgesLength

Alternatives

sobel_ampSobelAmp, kirsch_ampKirschAmp, frei_ampFreiAmp, robinson_ampRobinsonAmp, robertsRoberts

Module🔗

Foundation