corrects an input image for shading, using an analytic paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API ipsdk::image::ImagePtr	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 factor)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API void	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 factor, const ipsdk::image::ImagePtr &pOutImg)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API ipsdk::image::ImagePtr	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 offset, const ipReal64 factor)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API void	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 offset, const ipReal64 factor, const ipsdk::image::ImagePtr &pOutImg)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API ipsdk::image::ImagePtr	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const image::ImageConstPtr &pBlackImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 offset, const ipReal64 factor)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

IPSDKIPLINTENSITYTRANSFORM_API void	ipsdk::imaproc::itrans::paraboloidShadingCorrection2dImg (const image::ImageConstPtr &pInImg, const image::ImageConstPtr &pBlackImg, const ipsdk::imaproc::attr::ParaboloidParams3dConstPtr &pWhiteImgModel, const ipReal64 offset, const ipReal64 factor, const ipsdk::image::ImagePtr &pOutImg)
	wrapper function for Computes a shading-corrected image given in particular an offset and a factor, and a paraboloid model for the white image More...

Detailed Description

corrects an input image for shading, using an analytic paraboloid model for the white image

Corrects an input image for shading that may be introduced during its acquisition, using an analytic paraboloid model for the white image.

Given:

an input image
the parameters of the analytic equation of a paraboloid for the white image
an optional black image, , whose dimensions and data types are identical to input image dimensions and data types
a scalar offset
a scalar factor

Values of output image resulting from shading correction are computed as follows:

$OutImg[i] = \begin{cases} offset + factor.{\dfrac {InImg[i]-BlackImg[i]} {WhiteImg[i]-BlackImg[i]}} & \text { if } WhiteImg[i]-BlackImg[i] \ne 0 \\ offset & \text { otherwise} \end{cases}$

with:

i = (x, y, ...)
parameters are specified by the user through the ParaboloidParams3d data item; these parameters can be computed through the use of Paraboloid Image Fitting 2d algorithm

Here is an example of shading correction applied to a 8-bits grey level image on which an artificial vignetting has been applied:

Attributes description

Attribute description for algorithm :

Name	ToolTip	Default Initializer
ipsdk::imaproc::attr::InImg	[Input] image for processing operation	X
ipsdk::imaproc::attr::InOptBlackImg	[Input Optional] Black image, usually obtained by closing all optical ports of the camera, or by turning off all the light sources. Used by shading correction algorithm	X
ipsdk::imaproc::attr::InPIParaboloidParams3d	[Input] Plan indexed collection of 3d parameters of paraboloids	X
ipsdk::imaproc::attr::InOptOffset	[Input Optional] Offset. Used for instance by shading correction algorithm	X
ipsdk::imaproc::attr::InFactor	[Input] Multiplying factor. Used for instance by shading correction algorithm	X
ipsdk::imaproc::attr::OutImg	[Output] image for processing operation	ipsdk::imaproc::duplicateInOut (_pOutImg, _pInImg)

Global Rule description

Global rule description for algorithm :
ipsdk::imaproc::matchSize (_pInImg,_pOutImg) &&
ipsdk::imaproc::matchImagePlans (_pInPIParaboloidParams3d,_pInImg,eImagePlansMatchPolicy::eIPMP_ZCT) &&
ipsdk::processor::ifIsSet (_pInOptBlackImg,
ipsdk::imaproc::matchSizeAndType (_pInImg,_pInOptBlackImg))

Example of Python code :

Example imports

import PyIPSDK
import PyIPSDK.IPSDKIPLIntensityTransform as itrans
import PyIPSDK.IPSDKIPLFiltering as filter

Code Example

    # opening of input image
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    
    # retrieve white image paraboloid model
    paraboloidWhite, bResRead = PyIPSDK.readFromXmlFile(whiteParaboloidPath)
        
    # image shading correction computation
    outImg = itrans.paraboloidShadingCorrection2dImg(inImg, paraboloidWhite, 5.025, 254.02)
    

Example of C++ code :

Example informations

Associated library

IPSDKIPLIntensityTransform

Header file

#include <IPSDKIPL/IPSDKIPLIntensityTransform/Processor/ParaboloidShadingCorrection2dImg/ParaboloidShadingCorrection2dImg.h>

Code Example

    // open input image
    ImagePtr pInImg = loadTiffImageFile(inPath);
    // load white image paraboloid
    attr::ParaboloidParams3dPtr pParaboloid = boost::make_shared<attr::ParaboloidParams3d>();
    readFromXmlFile(whitePath, *pParaboloid);
    // open black image, if exists
    ImagePtr pBlackImg;
    pBlackImg = loadTiffImageFile(blackPath);
    const ipReal64 offset = .0;
    const ipReal64 factor = 255.0;
    ImagePtr pAutoOutImg = paraboloidShadingCorrection2dImg(pInImg, pBlackImg, pParaboloid, offset, factor);

See also: ParaboloidShadingCorrection2dImgLvl1; ParaboloidShadingCorrection2dImgLvl2; ParaboloidShadingCorrection2dImgLvl3