smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2smallest_rectangle2（算子）

名称

smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2smallest_rectangle2 — 具有任意方向的最小周围矩形。

签名

smallest_rectangle2(Regions : : : Row, Column, Phi, Length1, Length2)

描述

算子 smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2smallest_rectangle2 determines the smallest surrounding rectangle of a region, i.e., the rectangle with the smallest area of all rectangles containing the region. For this rectangle the center, the inclination and the two radii are calculated. The calculation of the rectangle is based on the center coordinates of the region pixels.

In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in the length and phi of their smallest surrounding rectangle.

The smallest surrounding rectangle of a region. Note that the calculation is based on the center coordinates of the region pixels.

The operator is applied when, for example, the location of a scenery of several regions (e.g., printed text on a rectangular paper or in rectangular print (justified lines)) must be found. The parameters of smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2smallest_rectangle2 are chosen in such a way that they can be used directly as input for the operators disp_rectangle2disp_rectangle2DispRectangle2DispRectangle2DispRectangle2disp_rectangle2 and gen_rectangle2gen_rectangle2GenRectangle2GenRectangle2GenRectangle2gen_rectangle2。

If more than one region is passed in RegionsRegionsRegionsRegionsregionsregions 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).

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

Regions to be examined.

RowRowRowRowrowrow (输出控制) rectangle2.center.y(-array) → (real)

中心行索引。

ColumnColumnColumnColumncolumncolumn (输出控制) rectangle2.center.x(-array) → (real)

中心列索引。

PhiPhiPhiPhiphiphi (输出控制) rectangle2.angle.rad(-array) → (real)

Orientation of the surrounding rectangle (arc measure)

Assertion: - pi / 2 < Phi && Phi <= pi / 2

Length1Length1Length1Length1length1length_1 (输出控制) rectangle2.hwidth(-array) → (real)

First radius (half length) of the surrounding rectangle.

Assertion: Length1 >= 0.0

Length2Length2Length2Length2length2length_2 (输出控制) rectangle2.hheight(-array) → (real)

Second radius (half width) of the surrounding rectangle.

Assertion: Length2 >= 0.0 && Length2 <= Length1

示例（HDevelop）

read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)

示例（HDevelop）

read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)

示例（HDevelop）

read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)

示例（HDevelop）

read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)

示例（HDevelop）

read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)

复杂度

If F is the area of the region and N is the number of supporting points of the convex hull, the runtime complexity is O(sqrt(F) + N^2).

结果

算子 smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2smallest_rectangle2 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>)。当空区域（区域是空集）时，可设置行为通过算子 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, runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeaturesrunlength_features

可能的后继

disp_rectangle2disp_rectangle2DispRectangle2DispRectangle2DispRectangle2disp_rectangle2, gen_rectangle2gen_rectangle2GenRectangle2GenRectangle2GenRectangle2gen_rectangle2

替代

elliptic_axiselliptic_axisEllipticAxisEllipticAxisEllipticAxiselliptic_axis, smallest_rectangle1smallest_rectangle1SmallestRectangle1SmallestRectangle1SmallestRectangle1smallest_rectangle1

另见

smallest_circlesmallest_circleSmallestCircleSmallestCircleSmallestCirclesmallest_circle, set_shapeset_shapeSetShapeSetShapeSetShapeset_shape

模块

基础

算子