//-----------------------------------------------------
// return a downsampled image (factor 1/2)
public MaskedImage downsample()
{
int newW=width/2, newH=height/2;
// Binomial coefficient
int[] kernel = {1,5,10,10,5,1};
MaskedImage newimage = new MaskedImage(newW, newH);
for(int y=0;y<height-1;y+=2) {
for(int x=0;x<width-1;x+=2) {
int r=0,g=0,b=0,m=0,ksum=0;
for(int dy=-2;dy<=3;dy++) {
int yk=y+dy;
if (yk<0 || yk>=height) continue;
int ky = kernel[2+dy];
for(int dx=-2;dx<=3;dx++) {
int xk = x+dx;
if (xk<0 || xk>=width) continue;
if (mask[xk,yk]) continue;
int k = kernel[2+dx]*ky;
r+= k*this.getSample(xk, yk, 0);
g+= k*this.getSample(xk, yk, 1);
b+= k*this.getSample(xk, yk, 2);
ksum+=k;
m++;
}
}
if (ksum>0) {r/=ksum; g/=ksum; b/=ksum;}
if (m!=0) {
newimage.setSample(x/2, y/2, 0, r);
newimage.setSample(x/2, y/2, 1, g);
newimage.setSample(x/2, y/2, 2, b);
newimage.setMask(x/2, y/2, false);
} else {
newimage.setMask(x/2, y/2, true);
}
}
}
return newimage;
}
//-----------------------------------------------------
// return an upscaled image
public MaskedImage upscale(int newW,int newH)
{
MaskedImage newimage = new MaskedImage(newW, newH);
for(int y=0;y<newH;y++) {
for(int x=0;x<newW;x++) {
// original pixel
int xs = (x*width)/newW;
int ys = (y*height)/newH;
// copy to new image
if (!mask[xs,ys]) {
newimage.setSample(x, y, 0, this.getSample(xs, ys, 0));
newimage.setSample(x, y, 1, this.getSample(xs, ys, 1));
newimage.setSample(x, y, 2, this.getSample(xs, ys, 2));
newimage.setMask(x, y, false);
} else {
newimage.setMask(x, y, true);
}
}
}
return newimage;
}
//-----------------------------------------------------
// Maximization Step : Maximum likelihood of target pixel
public void MaximizationStep(MaskedImage target, double[,,] vote)
{
for(int y=0;y<target.height;y++) {
for(int x=0;x<target.width;x++) {
if (vote[x,y,3]>0) {
int r = (int) ( vote[x,y,0]/vote[x,y,3] );
int g = (int) ( vote[x,y,1]/vote[x,y,3] );
int b = (int) ( vote[x,y,2]/vote[x,y,3] );
target.setSample(x, y, 0, r );
target.setSample(x, y, 1, g );
target.setSample(x, y, 2, b );
target.setMask(x,y,false);
} else {
// conserve the values from previous target
//target.setMask(x,y,true);
}
}
}
}