/**
* Applies a single threshold to a block of pixels.
*/
static void ThresholdBlock(const uint8_t* luminances, int xoffset, int yoffset, int threshold, int stride, BitMatrix& matrix)
{
for (int y = 0, offset = yoffset * stride + xoffset; y < BLOCK_SIZE; y++, offset += stride) {
for (int x = 0; x < BLOCK_SIZE; x++) {
// Comparison needs to be <= so that black == 0 pixels are black even if the threshold is 0.
if (luminances[offset + x] <= threshold) {
matrix.set(xoffset + x, yoffset + y);
}
}
}
}
// Applies a single threshold to an 8x8 block of pixels.
void LocalBlockBinarizer::threshold8x8Block(const unsigned char* luminances, int xoffset, int yoffset, int threshold,
int stride, BitMatrix& matrix) {
for (int y = 0; y < 8; y++) {
int offset = (yoffset + y) * stride + xoffset;
for (int x = 0; x < 8; x++) {
int pixel = luminances[offset + x];
if (pixel < threshold) {
matrix.set(xoffset + x, yoffset + y);
}
}
}
}