- Lightness (luminance): or simply known as brightness channel.
- Channel A: consist of colors from red to green, and
- Channel B: consist of colors from blue to yellow
Image below may already contain subtle artifacts and noise. We want to sharpen objects in an image without increasing the effect or visibility of those unwanted elements and also in a way that does not affect the original colors.
A brief note on Unsharp Mask before advancing:
Unsharp Mask is a filter that sharpens objects in an image, or in other words increase edge contrasts to objects in an image.