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Wish I had known this when I wrote a program that tracks a human wearing a shirt with a green square on it! The biggest issue with HSV was that it required a t

by Cyph0n 10y ago

Wish I had known this when I wrote a program that tracks a human wearing a shirt with a green square on it! The biggest issue with HSV was that it required a ton of tuning to compensate for ambient lighting conditions. Would Lab help with that, say by taking some range in -a and considering all of L? Or is that a separate problem entirely?

lettergram 10y ago
The L in Lab represents "light" (saturation). By removing or not looking at that channel, you are essentially looking at the normalized color channels. Look at the a channel (red to green) and b channel (yellow to blue) to get the color of the images. This essentially removes lighting conditions, although obviously lighting conditions still impact the image to some degree, from the camera and original RGB image.
- jayjay71 10y ago
  The L in HSL stands for lightness, and is similar to the L in Lab which also stands for lightness. Lab is meant to better represent how humans perceive color, but it's not inherently better for removing ambient lighting compared to HSL. The main difference between HSL and Lab is how good they are at distinguishing specific colors, and Lab tends to work better for things regarding human perception. I've always had better luck with HSL than Lab, but I tend to just try every color space when approaching a new problem. Also, removing glare and other lighting abnormalities is one of the banes of computer vision. To the best of my knowledge, nobody has figured out a good way to do it yet (although I've seen some promising work on dealing with occlusion, which you could use to overcome moderate glare with proper segmentation).
- mynewtb 10y ago
  Light intensity/amount, not saturation unless the word has a meaning I don't know.
  - lettergram 10y ago
    Light is more correct, but in the terms of HSV or RGB when you decrease saturation it changes the colors to white/black respectively, essentially decreasing the separation between colors.

by Cyph0n 10y ago

lettergram 10y ago

The L in Lab represents "light" (saturation). By removing or not looking at that channel, you are essentially looking at the normalized color channels. Look at the a channel (red to green) and b channel (yellow to blue) to get the color of the images. This essentially removes lighting conditions, although obviously lighting conditions still impact the image to some degree, from the camera and original RGB image.

jayjay71 10y ago
The L in HSL stands for lightness, and is similar to the L in Lab which also stands for lightness. Lab is meant to better represent how humans perceive color, but it's not inherently better for removing ambient lighting compared to HSL. The main difference between HSL and Lab is how good they are at distinguishing specific colors, and Lab tends to work better for things regarding human perception. I've always had better luck with HSL than Lab, but I tend to just try every color space when approaching a new problem. Also, removing glare and other lighting abnormalities is one of the banes of computer vision. To the best of my knowledge, nobody has figured out a good way to do it yet (although I've seen some promising work on dealing with occlusion, which you could use to overcome moderate glare with proper segmentation).
mynewtb 10y ago
Light intensity/amount, not saturation unless the word has a meaning I don't know.
- lettergram 10y ago
  Light is more correct, but in the terms of HSV or RGB when you decrease saturation it changes the colors to white/black respectively, essentially decreasing the separation between colors.