close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthclose_edges_length (算子)

名称

close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthclose_edges_length — 使用边缘振幅图像闭合边缘间隙。

签名

close_edges_length(Edges, Gradient : ClosedEdges : MinAmplitude, MaxGapLength : )

描述

close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthCloseEdgesLengthclose_edges_length closes gaps in the output of an edge detector, and thus tries to produce complete object contours. This operator expects as input the edges (EdgesEdgesEdgesEdgesedgesedges) and amplitude image (GradientGradientGradientGradientgradientgradient) returned by typical edge operators, such as edges_imageedges_imageEdgesImageEdgesImageEdgesImageedges_image or sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp。

Contours are closed in two steps: First, one pixel wide gaps in the input contours are closed, and isolated points are eliminated. After this, open contours are extended by up to MaxGapLengthMaxGapLengthMaxGapLengthMaxGapLengthmaxGapLengthmax_gap_length points by adding edge points until either the contour is closed or no more significant edge points can be found. A gradient is regarded as significant if it is larger than MinAmplitudeMinAmplitudeMinAmplitudeMinAmplitudeminAmplitudemin_amplitude. The neighboring points examined as possible new edge points are the point in the direction of the contour and its two adjacent points in an 8-neighborhood. For each of these points, the sum of its gradient and the maximum gradient of that points three possible neighbors is calculated (look ahead of length 1). The point with the maximum sum is then chosen as the new edge point.

注意

请注意，若使用域缩减后的图像作为输入，滤波器算子可能会返回意外结果。请参阅滤波器一章

执行信息

多线程类型：可重入（与非独占算子并行运行）。
多线程作用域：全局（可从任何线程调用）。
在元组级别上自动并行化。

参数

EdgesEdgesEdgesEdgesedgesedges (输入对象) region(-array) → object

Region containing one pixel thick edges.

GradientGradientGradientGradientgradientgradient (输入对象) singlechannelimage → object (byte / uint2)

Edge amplitude (gradient) image.

ClosedEdgesClosedEdgesClosedEdgesClosedEdgesclosedEdgesclosed_edges (输出对象) region(-array) → object

Region containing closed edges.

MinAmplitudeMinAmplitudeMinAmplitudeMinAmplitudeminAmplitudemin_amplitude (输入控制) integer → (integer)

最小边缘振幅。

默认值： 16

建议值： 5, 8, 10, 12, 16, 20, 25, 30, 40, 50

值范围： 0 ≤ MinAmplitude MinAmplitude MinAmplitude MinAmplitude minAmplitude min_amplitude ≤ 255

最小增量： 1

建议增量： 1

MaxGapLengthMaxGapLengthMaxGapLengthMaxGapLengthmaxGapLengthmax_gap_length (输入控制) integer → (integer)

Maximal number of points by which edges are extended.

默认值： 3

建议值： 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 30, 40, 50, 70, 100

值范围： 1 ≤ MaxGapLength MaxGapLength MaxGapLength MaxGapLength maxGapLength max_gap_length ≤ 127

最小增量： 1

建议增量： 1

示例（C）

sobel_amp(Image,&EdgeAmp,"sum_abs",5);
threshold(EdgeAmp,&EdgeRegion,40.0,255.0);
skeleton(EdgeRegion,&ThinEdge);
close_edges_length(ThinEdge,EdgeAmp,&CloseEdges,15,3);

结果

close_edges_lengthclose_edges_lengthCloseEdgesLengthCloseEdgesLengthCloseEdgesLengthclose_edges_length 在所有参数正确时返回 2 ( H_MSG_TRUE )。如果输入为空则可设置行为通过 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>)set_system("no_object_result",<Result>)。如有必要，则抛出异常。

可能的前趋

edges_imageedges_imageEdgesImageEdgesImageEdgesImageedges_image, sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp, thresholdthresholdThresholdThresholdThresholdthreshold, skeletonskeletonSkeletonSkeletonSkeletonskeleton

替代

close_edgesclose_edgesCloseEdgesCloseEdgesCloseEdgesclose_edges, dilation1dilation1Dilation1Dilation1Dilation1dilation1, closingclosingClosingClosingClosingclosing

参考文献

M. Üsbeck: “Untersuchungen zur echtzeitfähigen Segmentierung”; Studienarbeit, Bayerisches Forschungszentrum für Wissensbasierte Systeme (FORWISS), Erlangen, 1993.

模块

基础

算子