White Dark Gradient R Light R Dark G Light G Dark B Light B Dark

None Normalize Gray + Contrast Saturation Only Local Contrast Distance From White R-G Diff x5 R-B Diff x5 G-B Diff x5 Edges Soft Edges Hard Canny Gradient Detect Box Blur 5×5 Box Blur 11×11 Median 3×3 Median 5×5 Median 7×7 Bilateral Bilateral Strong Non-Local Means Hue Only Red Bit 5 Green Bit 5 Blue Bit 5