void Arc3DModel::GenerateGradientSmoothingMask(int subsampleFactor, QImage &OriginalTexture, CharImage &mask)
{
CharImage gray(OriginalTexture);
CharImage grad;
grad.resize(gray.w,gray.h);
int w=gray.w,h=gray.h;
for(int x=1;x<w-1;++x)
for(int y=1;y<h-1;++y)
{
int dx=abs(int(gray.Val(x,y))-int(gray.Val(x-1,y))) + abs(int(gray.Val(x,y))-int(gray.Val(x+1,y)));
int dy=abs(int(gray.Val(x,y))-int(gray.Val(x,y-1))) + abs(int(gray.Val(x,y))-int(gray.Val(x,y+1)));
grad.Val(x,y)=min(255,16*dx+dy);
}
// create subsampled mask
int ws=gray.w/subsampleFactor, hs=gray.h/subsampleFactor;
mask.resize(ws,hs);
for(int x=0;x<ws;++x)
for(int y=0;y<hs;++y)
{
unsigned char maxGrad=0;
for(int si=0;si<subsampleFactor;++si)
for(int sj=0;sj<subsampleFactor;++sj)
maxGrad = max(maxGrad, grad.Val(x*subsampleFactor+sj,y*subsampleFactor+si));
mask.Val(x,y) = maxGrad;
}
CharImage mask2;
mask2.resize(ws, hs);
// average filter (11 x 11)
int avg;
int wsize = 5;
for (int y = wsize; y < hs-wsize; y++)
for (int x = wsize; x < ws-wsize; x++)
{
avg = 0;
for (int yy = y - wsize; yy <= y + wsize; yy++)
for (int xx = x - wsize; xx <= x + wsize; xx++)
avg += mask.Val(xx, yy);
mask2.Val(x, y) = min(255, avg / ((2 * wsize + 1)* (2 * wsize +1)));
}
mask.convertToQImage().save("tmp_testmask.jpg","jpg");
mask2.convertToQImage().save("tmp_testmaskSmooth.jpg","jpg");
// erosion filter (7 x 7)
int minimum;
wsize = 3;
for (int y = wsize; y < hs-wsize; y++)
for (int x = wsize; x < ws-wsize; x++)
{
minimum = mask2.Val(x, y);
for (int yy = y - wsize; yy <= y + wsize; yy++)
for (int xx = x - wsize; xx <= x + wsize; xx++)
if (mask2.Val(xx, yy) < minimum)
minimum = mask2.Val(xx, yy);
mask.Val(x, y) = minimum;
}
grad.convertToQImage().save("tmp_test.jpg","jpg");
mask.convertToQImage().save("tmp_testmaskeroded.jpg","jpg");
}
