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/*
* Modification History
*
* 2001-May-15 Jeremy Tavan
* Created.
*
* 2001-May-16 Jeremy Tavan
* Modified to use the much faster quick_select
* median-finding algorithm.
*
* 2001-May-17 Jaosn Rohrer
* Tried to optimize by moving stuff out of the inner-inner loop.
* It helped a bit, but not much.
*
*/
#ifndef MEDIAN_FILTER_INCLUDED
#define MEDIAN_FILTER_INCLUDED
#include "minorGems/graphics/ChannelFilter.h"
#include "quickselect.h"
int medianFilterCompareInt( const void *x, const void *y );
/**
* Median convolution filter.
*
* @author Jeremy Tavan
*/
class MedianFilter : public ChannelFilter {
public:
/**
* Constructs a median filter.
*
* @param inRadius the radius of the box in pixels.
*/
MedianFilter( int inRadius );
/**
* Sets the box radius.
*
* @param inRadius the radius of the box in pixels.
*/
void setRadius( int inRadius );
/**
* Gets the box radius.
*
* @return the radius of the box in pixels.
*/
int getRadius();
// implements the ChannelFilter interface
void apply( double *inChannel, int inWidth, int inHeight );
private:
int mRadius;
};
inline MedianFilter::MedianFilter( int inRadius )
: mRadius( inRadius ) {
}
inline void MedianFilter::setRadius( int inRadius ) {
mRadius = inRadius;
}
inline int MedianFilter::getRadius() {
return mRadius;
}
inline void MedianFilter::apply( double *inChannel,
int inWidth, int inHeight ) {
// pre-compute an integer version of the channel for the
// median alg to use
int numPixels = inWidth * inHeight;
int *intChannel = new int[ numPixels ];
for( int p=0; p<numPixels; p++ ) {
intChannel[p] = (int)( 1000 * inChannel[p] );
}
double *medianChannel = new double[ inWidth * inHeight ];
// printf("inWidth = %d, inHeight = %d\n", inWidth, inHeight);
// printf("mRadius = %d\n",mRadius);
for( int y=0; y<inHeight; y++ ) {
int yIndexContrib = y * inWidth;
int startBoxY = y - mRadius;
int endBoxY = y + mRadius;
if( startBoxY < 0 ) {
startBoxY = 0;
}
if( endBoxY >= inHeight ) {
endBoxY = inHeight - 1;
}
int boxSizeY = endBoxY - startBoxY + 1;
for( int x=0; x<inWidth; x++ ) {
int startBoxX = x - mRadius;
int endBoxX = x + mRadius;
if( startBoxX < 0 ) {
startBoxX = 0;
}
if( endBoxX >= inWidth ) {
endBoxX = inWidth - 1;
}
int boxSizeX = endBoxX - startBoxX + 1;
int *buffer = new int[boxSizeX * boxSizeY];
// sum all pixels in the box around this pixel
for( int boxY = startBoxY; boxY<=endBoxY; boxY++ ) {
int yBoxIndexContrib = boxY * inWidth;
int yBoxContrib = boxSizeX * ( boxY-startBoxY );
for( int boxX = startBoxX; boxX<=endBoxX; boxX++ ) {
//buffer[boxSizeX*(boxY-startBoxY)+(boxX-startBoxX)] = (int)(1000.0 * inChannel[yBoxIndexContrib + boxX]);
buffer[ yBoxContrib + ( boxX-startBoxX ) ] = intChannel[ yBoxIndexContrib + boxX ];
}
}
medianChannel[ yIndexContrib + x ] = (double)quick_select( buffer, boxSizeX*boxSizeY ) / 1000.0;
delete [] buffer;
}
}
// copy blurred image back into passed-in image
memcpy( inChannel, medianChannel, sizeof(double) * inWidth * inHeight );
delete [] medianChannel;
delete [] intChannel;
}
#endif
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