lightness computation for an input color image More...

IPSDKIPLCOLOR_API void	ipsdk::imaproc::color::lightnessImg (const image::ImageConstPtr &pInColorImg, const image::ImagePtr &pOutLightImg)
	wrapper function for lightness computation from an input RGB color image More...

IPSDKIPLCOLOR_API image::ImagePtr	ipsdk::imaproc::color::lightnessImg (const image::ImageConstPtr &pInColorImg)
	wrapper function for lightness computation from an input RGB color image More...

IPSDKIPLCOLOR_API void	ipsdk::imaproc::color::lightnessImg (const image::ImageConstPtr &pInColorImg, const ipsdk::imaproc::attr::eLightnessType &lightnessType, const image::ImagePtr &pOutLightImg)
	wrapper function for lightness computation from an input RGB color image More...

IPSDKIPLCOLOR_API image::ImagePtr	ipsdk::imaproc::color::lightnessImg (const image::ImageConstPtr &pInColorImg, const ipsdk::imaproc::attr::eLightnessType &lightnessType)
	wrapper function for lightness computation from an input RGB color image More...

Detailed Description

lightness computation for an input color image

The algorithm converts a color image to a grey level one according to one of the three possible types: Average, Lightness or Luminance. The default value is Average.

Assuming that $InColorImg[i, c]$ is the $i^{th}$ pixel in the channel $c$ , we can define the three different ways to calculate the lightness.

For the Average type, the output image values are given by:

$OutLightImg[i] = \frac{\sum_{c}{InColorImg[i, c]}} {NbChannels}$

For the Lightness type, the output image values are given by:

$OutLightImg[i] = \frac{\max_{c}(InColorImg[i, c]) + \min_{c}(InColorImg[i, c])} {2}$

The Luminance type can only be calculated for images with three channels and is assumed to be RGB. The output image values are given by:

$OutLightImg[i] = 0.21 InColorImg[i, 0] + 0.72 InColorImg[i, 1] + 0.07 InColorImg[i, 2]$

Input and output images must have same size (but color size).

Here is an example of an average ligthness operation applied to a 8-bits RGB color image:

Attributes description

Attribute description for algorithm :

Name	ToolTip	Default Initializer
ipsdk::imaproc::attr::InColorImg	[Input] color image for processing operation	X
ipsdk::imaproc::attr::InLightnessType	[Input] Type of conversion to obtain a grey level image from a color image	X
ipsdk::imaproc::attr::OutLightImg	[Output] lightness image	duplicateGreyInOut (_pOutLightImg, _pInColorImg)

Global Rule description

Global rule description for algorithm :
ipsdk::imaproc::matchSize (eMatchImageSizeType::eMIST_XYZT,_pInColorImg,_pOutLightImg) &&
ipsdk::imaproc::matchBufferType (_pInColorImg,_pOutLightImg)

Example of Python code :

Example imports

import PyIPSDK

import PyIPSDK.IPSDKIPLColor as color

Code Example

    # opening of input image
    geometryRgb = PyIPSDK.geometryRgb2d(PyIPSDK.eImageBufferType.eIBT_UInt8, 510, 509)
    inImg = PyIPSDK.loadRawImageFile(inputImgPath,  geometryRgb)
    
    # lightness computation
    outImg = color.lightnessImg(inImg)

Example of C++ code :

Example informations

Associated library

IPSDKIPLColor

Header file

#include <IPSDKIPL/IPSDKIPLColor/Processor/LightnessImg/LightnessImg.h>

Code Example

        // opening input image
        ImagePtr pInColorImg = loadTiffImageFile(inputImgPath);
        
        // compute lightness on input image
        ImagePtr pOutLightImg = lightnessImg(pInColorImg, lightnessType);

See also: LightnessImgLvl1; LightnessImgLvl2; LightnessImgLvl3

Function Documentation

◆ lightnessImg() [1/4]

IPSDKIPLCOLOR_API void ipsdk::imaproc::color::lightnessImg	(	const image::ImageConstPtr &	pInColorImg,
		const image::ImagePtr &	pOutLightImg
	)

wrapper function for lightness computation from an input RGB color image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException on failure

◆ lightnessImg() [2/4]

IPSDKIPLCOLOR_API image::ImagePtr ipsdk::imaproc::color::lightnessImg ( const image::ImageConstPtr & pInColorImg )

wrapper function for lightness computation from an input RGB color image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException on failure

◆ lightnessImg() [3/4]

IPSDKIPLCOLOR_API void ipsdk::imaproc::color::lightnessImg	(	const image::ImageConstPtr &	pInColorImg,
		const ipsdk::imaproc::attr::eLightnessType &	lightnessType,
		const image::ImagePtr &	pOutLightImg
	)

wrapper function for lightness computation from an input RGB color image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException on failure

◆ lightnessImg() [4/4]

IPSDKIPLCOLOR_API image::ImagePtr ipsdk::imaproc::color::lightnessImg	(	const image::ImageConstPtr &	pInColorImg,
		const ipsdk::imaproc::attr::eLightnessType &	lightnessType
	)

wrapper function for lightness computation from an input RGB color image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException on failure