eccentricityeccentricityEccentricityEccentricityeccentricity（算子）

名称

eccentricityeccentricityEccentricityEccentricityeccentricity — 从椭圆参数导出的形状特征。

签名

描述

算子 eccentricityeccentricityEccentricityEccentricityEccentricityeccentricity calculates the three shape features AnisometryAnisometryAnisometryAnisometryanisometryanisometry, BulkinessBulkinessBulkinessBulkinessbulkinessbulkiness, and StructureFactorStructureFactorStructureFactorStructureFactorstructureFactorstructure_factor for the given RegionsRegionsRegionsRegionsregionsregions: where Ra and Rb denote the ellipse radii (see elliptic_axiselliptic_axisEllipticAxisEllipticAxisEllipticAxiselliptic_axis) and A denotes the area of the region (see area_centerarea_centerAreaCenterAreaCenterAreaCenterarea_center).

In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their anisometry, bulkiness and structure factor.

If more than one region is passed the results are stored in tuples, the index of a value in the tuple corresponding to the index of a region in the input.

In case of empty region all parameters have the value 0.0 if no other behavior was set (see set_systemset_systemSetSystemSetSystemSetSystemset_system).

注意

It should be noted that, like for all region-moments-based operators, the region's pixels are regarded as mathematical, infinitely small points that are represented by the center of the pixels (see the documentation of elliptic_axiselliptic_axisEllipticAxisEllipticAxisEllipticAxiselliptic_axis). This can lead to non-empty regions that have RbRbRbRbrbrb = 0. In these cases, the output features that require a division by RbRbRbRbrbrb are set to 0. In particular, regions that contain a single point or regions whose points lie exactly on a straight line (e.g., one pixel high horizontal regions or one pixel wide vertical regions) have an anisometry of 0.

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

复杂度

若 F 为区域面积，则平均运行时间复杂生为 O(√F)。

结果

算子 eccentricityeccentricityEccentricityEccentricityEccentricityeccentricity 在输入不为空时返回值 2 ( H_MSG_TRUE )。当输入为空（无可用输入区域）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>)。空区域（区域是空集）的情况下的可设置行为通过 set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)set_system("empty_region_result",<Result>)。如有必要，则抛出异常。

可能的前趋

thresholdthresholdThresholdThresholdThresholdthreshold, regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowingregiongrowing, connectionconnectionConnectionConnectionConnectionconnection

另见

elliptic_axiselliptic_axisEllipticAxisEllipticAxisEllipticAxiselliptic_axis, moments_region_2ndmoments_region_2ndMomentsRegion2ndMomentsRegion2ndMomentsRegion2ndmoments_region_2nd, select_shapeselect_shapeSelectShapeSelectShapeSelectShapeselect_shape, area_centerarea_centerAreaCenterAreaCenterAreaCenterarea_center

模块

基础