CODEWITHSUNDEEP
matlab
Callum
Callum

Reputation: 29

Matlab edit RGB values

I have buttons that need to increase\decrease an colour level for RGB. Tried doing something like this

im3 = im3(:,:,1) + 2;

but it creates some weird image glitch. any ideas? i'm not a pro so i'm probably going about this all wrong but any pointers would be much appreciated.

Upvotes: 2

Views: 948

Answers (1)

petrichor
petrichor

Reputation: 6569

There are a few things that you should consider:

  1. im3 = im3(:,:,1) + 2; assigns the new value to img3 variable and makes it a 2D matrix. You should do im3(:,:,1) = im3(:,:,1) + 2;. to increase all the values by 2 in third channel.
  2. Addition might result in larger values than the permitted values for an image. You may consider using imadd.
  3. Image variables are usually of type double or type uint8. If the values are double, the values are real and in between 0 and 1. If the values are unit8, the values are integers in between 0 and 255. Adding by 2 is reasonable if the type is uint8, but it is not when the type is double. You should add by 2/255 if so. You can use im2double or im2uint8 for type conversions with proper scaling. Be aware of the class of the img variable by running class(img).

Upvotes: 1

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