void R2Image::
Multiply(const R2Image& image)
{
// Multiply by image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
pixels[i] *= image.pixels[i];
}
}
void R2Image::
Subtract(const R2Image& image)
{
// Subtract image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
pixels[i] -= image.pixels[i];
}
}
void R2Image::
Divide(const R2Image& image)
{
// Add image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
if (image.pixels[i] == 0) {
if (pixels[i] == 0.0) continue;
else pixels[i] = FLT_MAX;
}
else {
pixels[i] /= image.pixels[i];
}
}
}
void R2Image::
Filter(const R2Image& filter)
{
// Get useful variables
int xr = filter.Width()/2;
int yr = filter.Height()/2;
R2Image copy(*this);
// This is the straight-forward implementation (slow for large filters)
for (int j = 0; j < Height(); j++) {
for (int i = 0; i < Width(); i++) {
for (int c = 0; c < NChannels(); c++) {
int fc = (NChannels() == filter.NChannels()) ? c : 0;
// Compute new value
double sum = 0;
for (int s = 0; s < filter.Width(); s++) {
int x = i - xr + s;
if (x < 0) x = 0;
else if (x >= Width()) x = Width()-1;
for (int t = 0; t < filter.Height(); t++) {
int y = j - yr + t;
if (y < 0) y = 0;
else if (y >= Height()) y = Height()-1;
double filter_value = filter.Value(s, t, fc);
double image_value = copy.Value(x, y, c);
sum += filter_value * image_value;
}
}
// Assign new value for channel
SetValue(i, j, c, sum);
}
}
}
}
