image =	bilateral2dImg (inImg,inSpaceSigma,inRangeSigma)
image =	bilateral2dImg (inImg,inHalfKnlSize,inSpaceSigma,inRangeSigma)

Detailed Description

bilateral filter on 2d image

The bilateral filter is a non-linear smoothing filter that has good properties of edge-preserving. Each pixel value is replaced by a weighted average of the values of its neighbours. The weight is a product of two gaussian functions, one depending on the euclidian distance between the central pixel and its current neighbour, the other depending on the difference of the intensities of these 2 pixels.

On output image values are given by:

$OutImg[x, y] = \dfrac { \sum_{o_y=-n}^{n}{\sum_{o_x=-n}^{n}{W(x, y, o_x, o_y)*InImg[x+o_x, y+o_y]}} } { \sum_{o_y=-n}^{n}{\sum_{o_x=-n}^{n}{W(x, y, o_x, o_y)}} }$

where:

is the weight function;
is the space function; $f_S(o_x, o_y)=e^{-\dfrac{o_x^2+o_y^2}{2*\sigma_S^2}}$
is the range function; $f_R(r)=e^{-\dfrac{r^2}{2*\sigma_R^2}}$
is defined by InOptHalfKnlSize attribute (if this attribute is not initialized, then equals to $1.5*\sigma_S$ )
$\sigma_R$ is defined by InRangeSigma attribute
$\sigma_S$ is defined by InSpaceSigma attribute

Input and output images must have same size.

Here is an example of a bilaterial filter applied to an 8-bits grey levels input image (with $\sigma_S=10.0$ and $\sigma_R=50.0$ ) :

See also: http://en.wikipedia.org/wiki/Bilateral_filter

Example of Python code :

Example imports

import PyIPSDK

import PyIPSDK.IPSDKIPLFiltering as filter

Code Example

    # opening of input images
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    
    # bilateral filter 2d computation
    outImg = filter.bilateral2dImg(inImg, 5, 3)

Example of C++ code :

Example informations

Header file

#include <IPSDKIPL/IPSDKIPLFiltering/Processor/Bilateral2dImg/Bilateral2dImg.h>

Code Example

        // definition of a custom output geometry
        ImageGeometryPtr pOutImageGeometry =
            geometry2d(outImageBufferType,
                       pInImg->getSizeX(),
                       pInImg->getSizeY());
        // creation of output image
        boost::shared_ptr<MemoryImage> pOutImg = boost::make_shared<MemoryImage>();
        pOutImg->init(*pOutImageGeometry);
        // compute bilateral filter on input image
        bilateral2dImg(pInImg, inHalfKnlSize, inSpaceSigma, inRangeSigma, pOutImg);