HALCON 17.12 / HALCON Operator Reference / Filters / Edges
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laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGauss (Operator)

Name

laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGauss — LoG-Operator (Laplace of Gaussian).

Signature

laplace_of_gauss(Image : ImageLaplace : Sigma : )

Herror laplace_of_gauss(const Hobject Image, Hobject* ImageLaplace, double Sigma)

Herror T_laplace_of_gauss(const Hobject Image, Hobject* ImageLaplace, const Htuple Sigma)

void LaplaceOfGauss(const HObject& Image, HObject* ImageLaplace, const HTuple& Sigma)

HImage HImage::LaplaceOfGauss(const HTuple& Sigma) const

HImage HImage::LaplaceOfGauss(double Sigma) const

static void HOperatorSet.LaplaceOfGauss(HObject image, out HObject imageLaplace, HTuple sigma)

HImage HImage.LaplaceOfGauss(HTuple sigma)

HImage HImage.LaplaceOfGauss(double sigma)

Description

laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss calculates the Laplace-of-Gaussian operator, i.e., the Laplace operator on a Gaussian smoothed image, for arbitrary smoothing parameters SigmaSigmaSigmaSigmasigma. The Laplace operator is given by:

The derivatives in laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss are calculated by appropriate derivatives of the Gaussian, resulting in the following formula for the convolution mask:

Attention

Note that filter operators may return may return unexpected results if an image with a reduced domain is used as input. Please refer to the chapter Filters.

Execution Information

Parameters

ImageImageImageImageimage (input_object)  (multichannel-)image(-array) → objectHImageHImageHobject (byte / int1 / int2 / uint2 / int4 / real)

Input image.

ImageLaplaceImageLaplaceImageLaplaceImageLaplaceimageLaplace (output_object)  (multichannel-)image(-array) → objectHImageHImageHobject * (int2)

Laplace filtered image.

SigmaSigmaSigmaSigmasigma (input_control)  number → HTupleHTupleHtuple (real / integer) (double / int / long) (double / Hlong) (double / Hlong)

Smoothing parameter of the Gaussian.

Default value: 2.0

Suggested values: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.0

Typical range of values: 0.7 ≤ Sigma Sigma Sigma Sigma sigma ≤ 5.0

Minimum increment: 0.01

Recommended increment: 0.1

Restriction: Sigma > 0.7 && Sigma <= 25.0

Example (C)

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

Possible Successors

zero_crossingzero_crossingZeroCrossingZeroCrossingZeroCrossing, dual_thresholddual_thresholdDualThresholdDualThresholdDualThreshold

Alternatives

laplacelaplaceLaplaceLaplaceLaplace, diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussDiffOfGauss, derivate_gaussderivate_gaussDerivateGaussDerivateGaussDerivateGauss

See also

derivate_gaussderivate_gaussDerivateGaussDerivateGaussDerivateGauss

Module

Foundation

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HALCON Operator Reference 17.12 Copyright © 1996-2017 MVTec Software GmbH