close_edgesclose_edgesclose_edgesCloseEdgesCloseEdges (Operator)

Name

close_edgesclose_edgesclose_edgesCloseEdgesCloseEdges — Close edge gaps using the edge amplitude image.

Signature

Description

close_edgesclose_edgesclose_edgesCloseEdgesCloseEdges closes gaps in the output of an edge detector, and thus tries to produce complete object contours. This is done by examining the neighbors of each edge point to determine the point with maximum amplitude (i.e., maximum gradient), and adding the point to the edge if its amplitude is larger than the minimum amplitude passed in MinAmplitudeMinAmplitudeMinAmplitudeMinAmplitudeminAmplitude. This operator expects as input the edges (EdgesEdgesEdgesEdgesedges) and amplitude image (EdgeImageEdgeImageEdgeImageEdgeImageedgeImage) returned by typical edge operators, such as edges_imageedges_imageedges_imageEdgesImageEdgesImage or sobel_ampsobel_ampsobel_ampSobelAmpSobelAmp. close_edgesclose_edgesclose_edgesCloseEdgesCloseEdges does not take into account the edge directions that may be returned by an edge operator. Thus, in areas where the gradient is almost constant the edges may become rather “wiggly.”

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.

Parameters

Example (C)

sobel_amp(Image,&EdgeAmp,"sum_abs",5);
threshold(EdgeAmp,&EdgeRegion,40.0,255.0);
skeleton(EdgeRegion,&ThinEdge);
close_edges(ThinEdge,EdgeAmp,&CloseEdges,15);
skeleton(CloseEdges,&ThinCloseEdges);

Result

close_edgesclose_edgesclose_edgesCloseEdgesCloseEdges 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

edges_imageedges_imageedges_imageEdgesImageEdgesImage, sobel_ampsobel_ampsobel_ampSobelAmpSobelAmp, thresholdthresholdthresholdThresholdThreshold, skeletonskeletonskeletonSkeletonSkeleton

Possible Successors

skeletonskeletonskeletonSkeletonSkeleton

Alternatives

close_edges_lengthclose_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLength, dilation1dilation1dilation1Dilation1Dilation1, closingclosingclosingClosingClosing

See also

gray_skeletongray_skeletongray_skeletonGraySkeletonGraySkeleton

Module

Foundation