Median 2d

Median filter on a 2d image. More...

Functions
IPSDKIPLFILTERING_API bool	ipsdk::imaproc::filter::median2dImg_allow8bitsCompression (const image::ImageConstPtr &pInImg, const ipUInt32 inHalfKnlSizeX, const ipUInt32 inHalfKnlSizeY, const image::ImagePtr &pOutImg)
	wrapper function for Median filter on a 2d image More...
IPSDKIPLFILTERING_API image::ImagePtr	ipsdk::imaproc::filter::median2dImg (const image::ImageConstPtr &pInImg, const ipUInt32 inHalfKnlSizeX, const ipUInt32 inHalfKnlSizeY)
	wrapper function for Median filter on a 2d image More...
IPSDKIPLFILTERING_API void	ipsdk::imaproc::filter::median2dImg (const image::ImageConstPtr &pInImg, const ipUInt32 inHalfKnlSizeX, const ipUInt32 inHalfKnlSizeY, const image::ImagePtr &pOutImg)
	wrapper function for Median filter on a 2d image More...

Detailed Description

Median filter on a 2d image.

The median filter is a non-linear filter used to reduce impulsive noise in an image while preserving edges.

The median filter computes, for each pixel of input image, the median of its neighbouring pixels.

On output image values are given by:

where :

• function applied to a set of cardinal ( is an odd positive integer) returns the element of the collection containing the elements of the set sorted by increasing value
• is defined by InHalfKnlSizeX attribute
• is defined by InHalfKnlSizeY attribute

Input and output images must have same size.

The algorithm is optimized if at least one of the following conditions is satisfied:

• and input image pixels are encoded on integers
• the kernel is a square of size 3 (in other words, and )
• the kernel is a square of size 5 (in other words, and )

If none of the previous conditions are satisfied, the user has all the same the possibility to execute a fast 2d median filter, by setting the attribute "InOutOptAllow8bitsCompression" to value true (this attribute is set to false by default). In this case, he will get a resulting image that will be an approximation of a real median (the resulting image will contain a maximum of 256 different grey level values).

Here are 2 examples of a median filter operation applied to a noised 8-bits grey levels input image:

• with :

• with :

See also

http://en.wikipedia.org/wiki/Median_filter

Attributes description

Attribute description for algorithm :

Name	ToolTip	Default Initializer
ipsdk::imaproc::attr::InImg	[Input] image for processing operation	X
ipsdk::imaproc::attr::InHalfKnlSizeX	[Input] half kernel size along X axis for operation	X
ipsdk::imaproc::attr::InHalfKnlSizeY	[Input] half kernel size along Y axis for operation	X
ipsdk::imaproc::attr::InOutOptAllow8bitsCompression	[InOut Optional] boolean determining whether 8 bits compression on output image is allowed to make median computation faster	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)

Example of Python code :

Example imports

import PyIPSDK
import PyIPSDK.IPSDKIPLFiltering as filter

Code Example

    # opening of input images
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    
    # median filter 2d computation
    outImg = filter.median2dImg(inImg, 3, 3)

Example of C++ code :

Example informations

Associated library

IPSDKIPLFiltering

Header file

#include <IPSDKIPL/IPSDKIPLFiltering/Processor/Median2dImg/Median2dImg.h>

Code Example

    // opening input image
    ImagePtr pInImg = loadTiffImageFile(inputImgPath);

    if(pInImg->getBufferType() != imageBufferType)
            pInImg = util::convertImg(pInImg, imageBufferType);

    // compute median on input image
    ImagePtr pOutImg = median2dImg(pInImg, inHalfKnlSizeX, inHalfKnlSizeY);

See also

Median2dImgLvl1

Function Documentation

median2dImg() [1/2]

IPSDKIPLFILTERING_API image::ImagePtr ipsdk::imaproc::filter::median2dImg	(	const image::ImageConstPtr &	pInImg,
		const ipUInt32	inHalfKnlSizeX,
		const ipUInt32	inHalfKnlSizeY
	)

wrapper function for Median filter on a 2d image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException

on failure

median2dImg_allow8bitsCompression()

IPSDKIPLFILTERING_API bool ipsdk::imaproc::filter::median2dImg_allow8bitsCompression	(	const image::ImageConstPtr &	pInImg,
		const ipUInt32	inHalfKnlSizeX,
		const ipUInt32	inHalfKnlSizeY,
		const image::ImagePtr &	pOutImg
	)

wrapper function for Median filter on a 2d image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException

on failure

Returns

flag indicating whether 8 bit compression has been used

median2dImg() [2/2]

IPSDKIPLFILTERING_API void ipsdk::imaproc::filter::median2dImg	(	const image::ImageConstPtr &	pInImg,
		const ipUInt32	inHalfKnlSizeX,
		const ipUInt32	inHalfKnlSizeY,
		const image::ImagePtr &	pOutImg
	)

wrapper function for Median filter on a 2d image

Exceptions

ipsdk::processor::IPSDKBaseProcessingException

on failure