points_harrisT_points_harrisPointsHarrisPointsHarrispoints_harris（算子）

名称

points_harrisT_points_harrisPointsHarrisPointsHarrispoints_harris — 使用哈里斯（Harris）算子检测兴趣点。

签名

描述

points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris extracts points of interest from an image. The Harris operator is based upon the smoothed matrix where stands for a Gaussian smoothing of size SigmaSmoothSigmaSmoothSigmaSmoothSigmaSmoothsigmaSmoothsigma_smooth and and are the first derivatives of each image channel, computed with Gaussian derivatives of size SigmaGradSigmaGradSigmaGradSigmaGradsigmaGradsigma_grad. The resulting points are the positive local extrema of If necessary, they can be restricted to points with a minimum filter response of ThresholdThresholdThresholdThresholdthresholdthreshold. The coordinates of the points are calculated with subpixel accuracy.

注意

points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris uses a special implementation that is optimized using SSE2 instructions if the system parameter 'sse2_enable'"sse2_enable""sse2_enable""sse2_enable""sse2_enable""sse2_enable" is set to 'true'"true""true""true""true""true" (which is default if SSE2 is available on your machine). This implementation is slightly inaccurate compared to the pure C version due to numerical issues (for 'byte' images the difference in RowRowRowRowrowrow and ColumnColumnColumnColumncolumncolumn is in order of magnitude of 1.0e-5). If you prefer accuracy over performance you can set 'sse2_enable'"sse2_enable""sse2_enable""sse2_enable""sse2_enable""sse2_enable" to 'false'"false""false""false""false""false" (using set_systemset_systemSetSystemSetSystemSetSystemset_system) before you call points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris. This way points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris does not use SSE2 accelerations. Don't forget to set 'sse2_enable'"sse2_enable""sse2_enable""sse2_enable""sse2_enable""sse2_enable" back to 'true'"true""true""true""true""true" afterwards.

points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris can be executed on an OpenCL device if both SigmaGradSigmaGradSigmaGradSigmaGradsigmaGradsigma_grad and SigmaSmoothSigmaSmoothSigmaSmoothSigmaSmoothsigmaSmoothsigma_smooth induce a filter size of no more than 129 pixels. This corresponds to a value of less than 20.7 for both parameters. As with the SSE2 version, the results of the OpenCL implementation may diverge slightly from that of pure C version due to numerical issues.

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

• 支持 OpenCL 计算设备。
• 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）。
• 在内部数据级别上自动并行化。

参数

结果

points_harrispoints_harrisPointsHarrisPointsHarrisPointsHarrispoints_harris returns 2 (H_MSG_TRUE) if all parameters are correct and no error occurs during the execution.当输入为空时，可设置行为通过算子 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。

可能的后继

gen_cross_contour_xldgen_cross_contour_xldGenCrossContourXldGenCrossContourXldGenCrossContourXldgen_cross_contour_xld

替代

points_foerstnerpoints_foerstnerPointsFoerstnerPointsFoerstnerPointsFoerstnerpoints_foerstner, points_lepetitpoints_lepetitPointsLepetitPointsLepetitPointsLepetitpoints_lepetit, points_harris_binomialpoints_harris_binomialPointsHarrisBinomialPointsHarrisBinomialPointsHarrisBinomialpoints_harris_binomial

参考文献

C. Harris, M. Stephens: “A combined corner and edge detector”. Proceedings of the 4th Alvey Vision Conference, pp. 147-151, 1988.
V. Gouet, N.Boujemaa: “Object-based queries using color points of interest”. IEEE Workshop on Content-Based Access of Image and Video Libraries, CVPR/CBAIVL 2001, Hawaii, USA, 2001.

模块

基础

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