critical_points_sub_pixT_critical_points_sub_pixCriticalPointsSubPixCriticalPointsSubPixcritical_points_sub_pix (算子)

名称

critical_points_sub_pixT_critical_points_sub_pixCriticalPointsSubPixCriticalPointsSubPixcritical_points_sub_pix — 图像中临界点的亚像素精确检测。

签名

描述

critical_points_sub_pixcritical_points_sub_pixCriticalPointsSubPixCriticalPointsSubPixCriticalPointsSubPixcritical_points_sub_pix extracts critical points, i.e., local maxima, local minima, and saddle points, from the image ImageImageImageImageimageimage with subpixel precision. To do so, in each point the input image is approximated by a quadratic polynomial in x and y and subsequently the polynomial is examined for extremal values and saddle points. The partial derivatives, which are necessary for setting up the polynomial, are calculated either with various Gaussian derivatives or using the facet model, depending on FilterFilterFilterFilterfilterfilter. In the first case, SigmaSigmaSigmaSigmasigmasigma determines the size of the Gaussian kernels, while in the second case, before being processed the input image is smoothed by a Gaussian whose size is determined by SigmaSigmaSigmaSigmasigmasigma. Therefore, 'facet'"facet""facet""facet""facet""facet" results in a faster extraction at the expense of slightly less accurate results. A point is accepted to be a critical point if the absolute values of both eigenvalues of the Hessian matrix are greater than ThresholdThresholdThresholdThresholdthresholdthreshold. The eigenvalues correspond to the curvature of the gray value surface. If both eigenvalues are negative, the point is a local maximum, if both are positive, a local minimum, and if they have different signs, a saddle 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）。
• 在内部数据级别上自动并行化。

参数

结果

critical_points_sub_pixcritical_points_sub_pixCriticalPointsSubPixCriticalPointsSubPixCriticalPointsSubPixcritical_points_sub_pix returns 2 ( H_MSG_TRUE) if all parameters are correct and no error occurs during the execution. 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。

可能的后继

gen_cross_contour_xldgen_cross_contour_xldGenCrossContourXldGenCrossContourXldGenCrossContourXldgen_cross_contour_xld, disp_crossdisp_crossDispCrossDispCrossDispCrossdisp_cross

替代

local_min_sub_pixlocal_min_sub_pixLocalMinSubPixLocalMinSubPixLocalMinSubPixlocal_min_sub_pix, local_max_sub_pixlocal_max_sub_pixLocalMaxSubPixLocalMaxSubPixLocalMaxSubPixlocal_max_sub_pix, saddle_points_sub_pixsaddle_points_sub_pixSaddlePointsSubPixSaddlePointsSubPixSaddlePointsSubPixsaddle_points_sub_pix

另见

local_minlocal_minLocalMinLocalMinLocalMinlocal_min, local_maxlocal_maxLocalMaxLocalMaxLocalMaxlocal_max, plateausplateausPlateausPlateausPlateausplateaus, plateaus_centerplateaus_centerPlateausCenterPlateausCenterPlateausCenterplateaus_center, lowlandslowlandsLowlandsLowlandsLowlandslowlands, lowlands_centerlowlands_centerLowlandsCenterLowlandsCenterLowlandsCenterlowlands_center

模块

基础

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