compactnesscompactnessCompactnessCompactnesscompactness（算子）

名称

compactnesscompactnessCompactnessCompactnesscompactness — 区域紧凑性的形状系数。

签名

描述

算子 compactnesscompactnessCompactnessCompactnessCompactnesscompactness calculates the compactness of the input regions.

Calculation：

If L is the length of the contour (see contlengthcontlengthContlengthContlengthContlengthcontlength) and F the area of the region the shape factor C is defined as:

C = max(1,C')

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

The shape factor C of a circle is 1. If the region is long or has holes C is larger than 1. The operator compactnesscompactnessCompactnessCompactnessCompactnesscompactness responds to the course of the contour (roughness) and to holes. The value of C is clipped to 1.0, because the pixel area of a region can only be an approximation of a real circle's area. This approximation error is bigger for small regions than for large regions.

In case of an empty region the operator compactnesscompactnessCompactnessCompactnessCompactnesscompactness returns the value 0 if no other behavior was set (see set_systemset_systemSetSystemSetSystemSetSystemset_system). If more than one region is passed the numerical values of the shape factor are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.

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

结果

算子 compactnesscompactnessCompactnessCompactnessCompactnesscompactness 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

替代

convexityconvexityConvexityConvexityConvexityconvexity, eccentricityeccentricityEccentricityEccentricityEccentricityeccentricity

另见

contlengthcontlengthContlengthContlengthContlengthcontlength, area_centerarea_centerAreaCenterAreaCenterAreaCenterarea_center, select_shapeselect_shapeSelectShapeSelectShapeSelectShapeselect_shape

模块

基础