1

I had a job interview recently about image processing stuff, in that interview they had a question about convert RGB space to Gray Space(it's an easy question in first thought) so I answered: we can performed this task by using below equation:

Gray = 0.299 * R + 0.578 * G + 0.114 * B

but one of them said it's not true and he proposed below equation:

Gray=(R+G+B)/3

but I had seen my proposed equation before in this link and this and I said, of course, we can take average in channels but first one gave better performance and we argued about it, after a while one of them said in CMOS and CCD cameras this converting is different. is that true?

Thanks

Saeed Masoomi
  • 1,703
  • 1
  • 19
  • 33
  • Go through [this](https://en.wikipedia.org/wiki/Grayscale) page. I think what you proposed is LUMA coding. But there are other strategies of conversion too. Which one is used when requires more in-depth reading. I may be wrong, but I don't think SO is the right place for this question – absin Feb 05 '18 at 06:28
  • @AbSin, Thanks man, but what I want to know is relation between this conversion and camera sensors, and about second one I had seen this kind of question before :)) – Saeed Masoomi Feb 05 '18 at 06:42
  • @saeedmasoomi you answered right but by saying 'but one of them said it's not true and he proposed below equation:' , i think interviewer wanted to know other options(specific to different applications) available for rgb to gray conversion and there significances. I find this one https://stackoverflow.com/a/689547/5545458 helpfull. – flamelite Feb 05 '18 at 07:16

1 Answers1

0

What you answered is absolutely right and there is no question about it.

If the question is to match the Color Quality of two different camera's (CCD & CMOS) then we need to use appropriate Color Mapping functions to match the output of two cameras.

Note that not all the cameras will produce same colors as the other one. Not only the cameras but also the device that is used to view the colors/Image. That is why we have Color Management Engines to Map one device with the other.

Balaji R
  • 1,805
  • 22
  • 41