detect_edge_segmentsT_detect_edge_segmentsDetectEdgeSegmentsDetectEdgeSegmentsdetect_edge_segments (算子)

名称

detect_edge_segmentsT_detect_edge_segmentsDetectEdgeSegmentsDetectEdgeSegmentsdetect_edge_segments — 检测直边段。

签名

描述

detect_edge_segmentsdetect_edge_segmentsDetectEdgeSegmentsDetectEdgeSegmentsDetectEdgeSegmentsdetect_edge_segments detects straight edge segments in the gray image ImageImageImageImageimageimage. The extracted edge segments are returned as line segments with start point (BeginRowBeginRowBeginRowBeginRowbeginRowbegin_row,BeginColBeginColBeginColBeginColbeginColbegin_col) and end point (EndRowEndRowEndRowEndRowendRowend_row,EndColEndColEndColEndColendColend_col). Edge detection is based on the Sobel filter, using 'sum_abs'"sum_abs""sum_abs""sum_abs""sum_abs""sum_abs" as parameter and SobelSizeSobelSizeSobelSizeSobelSizesobelSizesobel_size as the filter mask size (see sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp). Only pixels with a filter response larger than MinAmplitudeMinAmplitudeMinAmplitudeMinAmplitudeminAmplitudemin_amplitude are used as candidates for edge points. These thresholded edge points are thinned and split into straight segments. Due to technical reasons, edge points in which several edges meet are lost. Therefore, detect_edge_segmentsdetect_edge_segmentsDetectEdgeSegmentsDetectEdgeSegmentsDetectEdgeSegmentsdetect_edge_segments usually does not return closed object contours. The parameter MaxDistanceMaxDistanceMaxDistanceMaxDistancemaxDistancemax_distance controls the maximum allowed distance of an edge point to its approximating line. For efficiency reasons, the sum of the absolute values of the coordinate differences is used instead of the Euclidean distance. MinLengthMinLengthMinLengthMinLengthminLengthmin_length controls the minimum length of the line segments. Lines shorter than MinLengthMinLengthMinLengthMinLengthminLengthmin_length are not returned.

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

示例（C）

Htuple  SobelSize,MinAmplitude,MaxDistance,MinLength;
Htuple  RowBegin,ColBegin,RowEnd,ColEnd;

create_tuple(&SobelSize,1);
set_i(SobelSize,5,0);
create_tuple(&MinAmplitude,1);
set_i(MinAmplitude,32,0);
create_tuple(&MaxDistance,1);
set_i(MaxDistance,3,0);
create_tuple(&MinLength,1);
set_i(MinLength,10,0);
T_detect_edge_segments(Image,SobelSize,MinAmplitude,MaxDistance,MinLength,
                &RowBegin,&ColBegin,&RowEnd,&ColEnd);

结果

detect_edge_segmentsdetect_edge_segmentsDetectEdgeSegmentsDetectEdgeSegmentsDetectEdgeSegmentsdetect_edge_segments 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

sigma_imagesigma_imageSigmaImageSigmaImageSigmaImagesigma_image, median_imagemedian_imageMedianImageMedianImageMedianImagemedian_image

可能的后继

partition_linespartition_linesPartitionLinesPartitionLinesPartitionLinespartition_lines, line_positionline_positionLinePositionLinePositionLinePositionline_position, line_orientationline_orientationLineOrientationLineOrientationLineOrientationline_orientation

替代

sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp, thresholdthresholdThresholdThresholdThresholdthreshold, skeletonskeletonSkeletonSkeletonSkeletonskeleton

模块

基础

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