symmetrysymmetrySymmetrySymmetrysymmetry（算子）

名称

symmetrysymmetrySymmetrySymmetrysymmetry — 一行灰度值的对称性。

签名

symmetry(Image : ImageSymmetry : MaskSize, Direction, Exponent : )

描述

symmetrysymmetrySymmetrySymmetrySymmetrysymmetry calculates the symmetry along a line. For each pixel the gray values of both sides of the line are compared: The absolute value of the differences of gray values with same distance to the pixel is computed. Each of these differences is weighted by the exponent (after division by 255) and then summed up. Pixels with a high symmetry have large gray values.

注意

Currently only horizontal search lines are implemented. Note that the parameter DirectionDirectionDirectionDirectiondirectiondirection exists for future extensions and can currently only have the value 0.0.

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）。
在元组级别上自动并行化。
在通道级别上自动并行化。
在域级别上自动并行化。

参数

ImageImageImageImageimageimage (输入对象) (multichannel-)image(-array) → object (byte)

输入图像。

ImageSymmetryImageSymmetryImageSymmetryImageSymmetryimageSymmetryimage_symmetry (输出对象) (multichannel-)image(-array) → object (byte)

Symmetry image.

MaskSizeMaskSizeMaskSizeMaskSizemaskSizemask_size (输入控制) number → (integer)

Extension of search area.

默认值： 40

建议值： 3, 5, 7, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 100, 120, 140, 180

值范围： 3 ≤ MaskSize MaskSize MaskSize MaskSize maskSize mask_size ≤ 1000

最小增量： 1

建议增量： 2

DirectionDirectionDirectionDirectiondirectiondirection (输入控制) number → (real)

Angle of test direction.

默认值： 0.0

建议值： 0.0

值范围： 0.0 ≤ Direction Direction Direction Direction direction direction ≤ 0.0

ExponentExponentExponentExponentexponentexponent (输入控制) number → (real)

Exponent for weighting.

默认值： 0.5

建议值： 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 0.8, 0.9, 1.0

最小增量： 0.01

建议增量： 0.1

限制： 0 < Exponent && Exponent <= 100

示例（HDevelop）

read_image(Image,'monkey')
symmetry(Image,ImageSymmetry,70,0.0,0.5)
threshold(ImageSymmetry,SymmPoints,170,255)

结果

如果参数值正确，算子 symmetrysymmetrySymmetrySymmetrySymmetrysymmetry 返回值 2 (H_MSG_TRUE)当输入为空（无可用输入图像）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>)。如有必要，则抛出异常。

可能的后继

thresholdthresholdThresholdThresholdThresholdthreshold

模块

基础

算子