Compute X, Y and Z gradients of an input image convolving it with 3d Sobel kernels. More...

IPSDKIPLFILTERING_API GradientXYZImg	ipsdk::imaproc::filter::sobelGradient3dImg (const image::ImageConstPtr &pInImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API GradientXYZImg	ipsdk::imaproc::filter::sobelGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API void	ipsdk::imaproc::filter::sobelGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize, const image::ImagePtr &pOutOptGradXImg, const image::ImagePtr &pOutOptGradYImg, const image::ImagePtr &pOutOptGradZImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelXGradient3dImg (const image::ImageConstPtr &pInImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelXGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API void	ipsdk::imaproc::filter::sobelXGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize, const image::ImagePtr &pOutXGradImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelYGradient3dImg (const image::ImageConstPtr &pInImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelYGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API void	ipsdk::imaproc::filter::sobelYGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize, const image::ImagePtr &pOutYGradImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelZGradient3dImg (const image::ImageConstPtr &pInImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::sobelZGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

IPSDKIPLFILTERING_API void	ipsdk::imaproc::filter::sobelZGradient3dImg (const image::ImageConstPtr &pInImg, const ipsdk::eSobelKernelType &kernelType, const bool bNormalize, const image::ImagePtr &pOutYGradImg)
	wrapper function for Sobel filter used to compute gradient on a 2d image More...

Detailed Description

Compute X, Y and Z gradients of an input image convolving it with 3d Sobel kernels.

3d Sobel kernels are separable, they can be decomposed as the product of 3 vectors. X gradient kernel equals to the product $V_{smoothing}*V_{smoothing}*V_{deriv}$ , Y gradient kernel equals to the product $V_{smoothing}*V_{deriv}*V_{smoothing}$ , and Z gradient kernel equals to the product $V_{deriv}*V_{smoothing}*V_{smoothing}$ . Depending on the value of parameter $InOptSobelKernelType$ (default value: eSKT_SobelHalfKnlSz1), smoothing and derivative vectors equal to:

$V_{smoothing}=\begin{bmatrix} 1 & 2 & 1 \end{bmatrix}$ , $V_{deriv}=\begin{bmatrix} -1 & 0 & 1 \end{bmatrix}$ if equals to eSKT_SobelHalfKnlSz1
$V_{smoothing}=\begin{bmatrix} 3 & 10 & 3 \end{bmatrix}$ , $V_{deriv}=\begin{bmatrix} -1 & 0 & 1 \end{bmatrix}$ if equals to eSKT_ScharrHalfKnlSz1
$V_{smoothing}=\begin{bmatrix} 1 & 4 & 6 & 4 & 1 \end{bmatrix}$ , $V_{deriv}=\begin{bmatrix} -1 & -2 & 0 & 2 & 1 \end{bmatrix}$ if equals to eSKT_SobelHalfKnlSz2
$V_{smoothing}=\begin{bmatrix} 1 & 6 & 15 & 20 & 15 & 6 & 1 \end{bmatrix}$ , $V_{deriv}=\begin{bmatrix} -1 & -4 & -5 & 0 & 5 & 4 & 1 \end{bmatrix}$ if equals to eSKT_SobelHalfKnlSz3

has the default value . When the user sets this parameter to the value , only the smoothing part of the 2d kernel is normalized.

To handle image borders, a mirror extrapolation is used (see Border policy for more details).

Here is an example of a Sobel gradient applied to an 8-bits grey levels input image with default parameters used:

See also: https://en.wikipedia.org/wiki/Sobel_operator

Attributes description

Attribute description for algorithm :

Name	ToolTip	Default Initializer
ipsdk::imaproc::attr::InImg3d	[Input] 3d image for operation	X
ipsdk::imaproc::attr::InOptSobelKernelType	[Input Optional] kernel type for Sobel gradient filter	X
ipsdk::imaproc::attr::InOptNormalizeSobelKernel	[Input Optional] boolean flag indicating whether kernel use for Sobel gradient filtering has to be normalized or not	X
ipsdk::imaproc::attr::OutOptGradXImg3d	[Output Optional] 3d image associated to X component of gradient computation	promoteUnary (_pOutOptGradXImg3d, _pInImg3d, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutOptGradYImg3d	[Output Optional] 3d image associated to Y component of gradient computation	promoteUnary (_pOutOptGradYImg3d, _pInImg3d, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutOptGradZImg3d	[Output Optional] 3d image associated to Z component of gradient computation	promoteUnary (_pOutOptGradZImg3d, _pInImg3d, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)

Global Rule description

Global rule description for algorithm :
((ipsdk::processor::isSet (_pOutOptGradXImg3d) ||
  ipsdk::processor::isSet (_pOutOptGradYImg3d) ||
  ipsdk::processor::isSet (_pOutOptGradZImg3d)) &&
(ipsdk::processor::ifIsSet (_pOutOptGradXImg3d,
   ipsdk::imaproc::matchSize (_pInImg3d,_pOutOptGradXImg3d))) &&
(ipsdk::processor::ifIsSet (_pOutOptGradYImg3d,
   ipsdk::imaproc::matchSize (_pInImg3d,_pOutOptGradYImg3d))) &&
(ipsdk::processor::ifIsSet (_pOutOptGradZImg3d,
   ipsdk::imaproc::matchSize (_pInImg3d,_pOutOptGradZImg3d))))

Example of Python code :

Example imports

import PyIPSDK

import PyIPSDK.IPSDKIPLFiltering as filter

Code Example

    # opening of input images
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    
    # Sobel gradient filter 3d computation
    outGxImg,  outGyImg,  outGzImg = filter.sobelGradient3dImg(inImg)

Example of C++ code :

Example informations

Associated library

IPSDKIPLFiltering

Header file

#include <IPSDKIPL/IPSDKIPLFiltering/Processor/SobelGradient3dImg/SobelGradient3dImg.h>

Code Example

    // opening input 3D image from TIFF file
    ImagePtr pInImg = loadTiffImageFile(inputImgPath, eTiffDirectoryMode::eTDM_Volume);
    // applying Sobel gradient to input image
    GradientXYZImg gradientXYZ = sobelGradient3dImg(pInImg);

See also: SobelGradient3dImgLvl1

Function Documentation

◆ sobelGradient3dImg() [1/3]

IPSDKIPLFILTERING_API GradientXYZImg ipsdk::imaproc::filter::sobelGradient3dImg ( const image::ImageConstPtr & pInImg )