diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussdiff_of_gauss (算子)

名称

diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussdiff_of_gauss — 近似LoG算子（高斯拉普拉斯）。

签名

diff_of_gauss(Image : DiffOfGauss : Sigma, SigFactor : )

描述

diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussDiffOfGaussdiff_of_gauss approximates the Laplace-of-Gauss operator by a difference of Gaussians. The standard deviations of these Gaussians can be calculated, according to Marr, from the Parameter SigmaSigmaSigmaSigmasigmasigma of the LoG and the ratio of the two standard deviations (SigFactorSigFactorSigFactorSigFactorsigFactorsig_factor) as:

For a , according to Marr, an approximation to the Mexican-Hat-Operator results. The resulting image is stored in DiffOfGaussDiffOfGaussDiffOfGaussDiffOfGaussdiffOfGaussdiff_of_gauss。

注意

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 / uint2)

Input image

DiffOfGaussDiffOfGaussDiffOfGaussDiffOfGaussdiffOfGaussdiff_of_gauss (输出对象) (multichannel-)image(-array) → object (int2)

LoG image.

SigmaSigmaSigmaSigmasigmasigma (输入控制) real → (real)

Smoothing parameter of the Laplace operator to approximate.

默认值： 3.0

建议值： 2.0, 3.0, 4.0, 5.0

最小增量： 0.01

建议增量： 0.1

限制： Sigma > 0.0

SigFactorSigFactorSigFactorSigFactorsigFactorsig_factor (输入控制) real → (real)

Ratio of the standard deviations used (Marr recommends 1.6).

默认值： 1.6

最小增量： 0.01

建议增量： 0.1

限制： SigFactor > 0.0

示例（HDevelop）

read_image(Image,'fabrik')
diff_of_gauss(Image,Laplace,2.0,1.6)
zero_crossing(Laplace,ZeroCrossings)

示例（C）

read_image(&Image,"mreut");
diff_of_gauss(Image,&Laplace,2.0,1.6);
zero_crossing(Laplace,&ZeroCrossings);

示例（HDevelop）

read_image(Image,'fabrik')
diff_of_gauss(Image,Laplace,2.0,1.6)
zero_crossing(Laplace,ZeroCrossings)

示例（HDevelop）

read_image(Image,'fabrik')
diff_of_gauss(Image,Laplace,2.0,1.6)
zero_crossing(Laplace,ZeroCrossings)

示例（HDevelop）

read_image(Image,'fabrik')
diff_of_gauss(Image,Laplace,2.0,1.6)
zero_crossing(Laplace,ZeroCrossings)

复杂度

The execution time depends linearly on the number of pixels and the size of sigma.

结果

diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussDiffOfGaussdiff_of_gauss 在所有参数正确时返回 2 ( H_MSG_TRUE )。如果输入为空则可设置行为通过 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

zero_crossingzero_crossingZeroCrossingZeroCrossingZeroCrossingzero_crossing, dual_thresholddual_thresholdDualThresholdDualThresholdDualThresholddual_threshold

替代

laplacelaplaceLaplaceLaplaceLaplacelaplace, derivate_gaussderivate_gaussDerivateGaussDerivateGaussDerivateGaussderivate_gauss

参考文献

D. Marr: “Vision (A computational investigation into human representation and processing of visual information)”; New York, W.H. Freeman and Company; 1982.

模块

基础

算子