circularitycircularityCircularityCircularitycircularity（算子）

名称

circularitycircularityCircularityCircularitycircularity — 区域圆形度（与圆的相似性）的形状系数。

签名

circularity(Regions : : : Circularity)

描述

算子 circularitycircularityCircularityCircularityCircularitycircularity calculates the similarity of the input region with a circle.

Calculation：

If F is the area of the region and max is the maximum distance from the center to all contour pixels, the shape factor C is defined as:

C = min(1,C')

The shape factor C of a circle is 1. If the region is long or has holes, C is smaller than 1. The operator circularitycircularityCircularityCircularityCircularitycircularity especially responds to large bulges, holes and unconnected regions. 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 the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their circularity.

In case of an empty region the operator circularitycircularityCircularityCircularityCircularitycircularity 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

RegionsRegionsRegionsRegionsregionsregions (输入对象) region(-array) → object

待检查的区域。

CircularityCircularityCircularityCircularitycircularitycircularity (输出控制) real(-array) → (real)

Circularity of the input region(s).

Assertion: 0 <= Circularity && Circularity <= 1.0

示例（HDevelop）

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

示例（C）

/* Comparison between shape factors of rectangle, circle and ellipse */
gen_rectangle1(&R1,10.0,10.0,20.0,20.0);
gen_rectangle2(&R2,100.0,100.0,0.0,100.0,20.0);
gen_ellipse(&E,100.0,100.0,0.0,100.0,20.0);
gen_circle(&C,100.0,100.0,20.0);
circularity(R1,&R1_);
circularity(R2,&R2_);
circularity(E,&E_);
circularity(C,&C_);
printf("quadrate:   %g\n",R1_);
printf("rectangle:  %g\n",R2_);
printf("ellipse:    %g\n",E_);
printf("circle:     %g\n",C_);

示例（HDevelop）

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

示例（HDevelop）

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

示例（HDevelop）

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

结果

算子 circularitycircularityCircularityCircularityCircularitycircularity 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

roundnessroundnessRoundnessRoundnessRoundnessroundness, compactnesscompactnessCompactnessCompactnessCompactnesscompactness, convexityconvexityConvexityConvexityConvexityconvexity, eccentricityeccentricityEccentricityEccentricityEccentricityeccentricity

另见

area_centerarea_centerAreaCenterAreaCenterAreaCenterarea_center, select_shapeselect_shapeSelectShapeSelectShapeSelectShapeselect_shape

模块

基础

算子