MATLAB Answers

Convert color to value

조회 수: 25(최근 30일)
Xin 30 Nov 2017
댓글: Image Analyst 30 Nov 2017
Hello everyone. I have a jpg image with blue to red color corresponding to different value. There is also a colorbar showing each colorscale correspond to a value. Is there a simple way to convert this color image into matrix? Thanks a lot.

채택된 답변

Jos (10584)
Jos (10584) 30 Nov 2017
So you have combinations of red and blue colour values (R,B) that correspond to a some arbitrary single values V according to the colour scale. Perhaps 2D interpolation, will work for you:
Extract all the the (R,B) combinations for each pixel (Rq,Bq)
Vq = interp2(R,B,V,Rq,Bq)
If the green channel is also important, use interp3.

추가 답변(2개)

Image Analyst
Image Analyst 30 Nov 2017
See my attached demo where I used the colormap in a thermal image to convert that into a grayscale temperature image.

Stephen Cobeldick
Stephen Cobeldick 30 Nov 2017
Use rgb2ind.
  댓글 수: 2
Image Analyst
Image Analyst 30 Nov 2017
That's the gist of it, but it's not that simple unless you already have the colormap. In many cases, the user does not and has only some kind of screenshot. My solution also uses rgb2ind() but also does the hard part of figuring out how to obtain the colormap.

댓글을 달려면 로그인하십시오.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by