Talk:Channel (digital image)

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Delta channel

I've heard things about a "delta channel" or "z-depth channel", which represents the distance between the pixel's source and the viewer/camera. It effectively shows where the pixels are located in 3D space.

It can allow a compositor to remove the background from an image, akin to color keying, and overlay the trimmed image on another background.
An image editor can use it to alter depth-of-field, blurring or sharpening/deconvoluting selected ranges.

—Nahum Reduta 02:10, 19 May 2007 (UTC)[reply]

relation to grayscale image

"A channel in this context is the grayscale image of the same size as a color image," "a channel in this case is extended to be the grayscale image based on any such conventional primary color. By extension, a channel is any grayscale image of the same dimension as and associated with the original image. " These are not clear. The luma component in Y′CbCr/YCbCr color encoding is/can be; and individual R, G and B channels also can be (each rendering different grayscale results), when the channels are not assigned/mapped to R, G and B, or when interpreted as grayscale. Couldn't find the reason behind this definition/approach in history or talk pages. ı would like to learn more and it may also be detailed in the article. — Preceding unsigned comment added by 95.70.244.200 (talk) 10:03, 24 January 2021 (UTC)[reply]