How to convert Lab to RGB image and its matlab code?

In my program,first converted rgb image to lab but after processing the image , i want convert Lab to rgb image. so i request you, pls provide matlab code for converting lab to rgb image?

Answer 1

[Thorsten]

help cform tells you

 rgb = imread('peppers.png');
 cform = makecform('srgb2lab');
 lab = applycform(rgb, cform);

[somasekar jalari]

the above matlab code is for rgb to lab but not converse. thanks.

[Thorsten]

That's just another cform:

 cform_lab2srgb = makecform('lab2srgb');
 rgb = applycform(lab, cform_lab2srgb);

[somasekar jalari]

thank you.its working well. i need mathematical equations for documentation purpose to convert CIELab to rgb image. is there link pls?

thanks in advance.

[Image Analyst]

For standard "book formulas" you can go to http://www.easyrgb.com/index.php?X=MATH. I rarely use book formulas if you need actual LAB values like you'd get from a spectrophotometer or chromameter. Why? Well, an object has an intrinsic LAB color but if you snap images with a camera, you can get virtually whatever RGB values you want out of it by adjusting exposure or other camera parameters. Of course all those different RGB values will give different LAB values if you just use the book formula, NOT the true intrinsic LAB values. In what I do, I need accurate LAB values, not arbitrary ones.

[zee falcon]

I want to convert rgb images to lab. But above code is not working.It not shows any output after the conversion.Help me out

[Stephen23]

@zee falcon: what output do you expect? How are you checking it?

[Image Analyst]

zee, you can also use rgb2lab(). But like Steven asked, what output are you expecting? You get an image. And do see that image you can use imshow(), or you can just look at it's values in the variable editor in the workspace. But no output will get "shown" unless you do one of those two things. Otherwise all you get is a new variable.

Answer 2

[Image Analyst]

Try this

labImage = rgb2lab(rgbImage);

[Image Analyst]

For the reverse direction, it's

rgbImage = lab2rgb(labImage);

There are also options that you can specify -- see the help.

[somasekar jalari]

thank you

[zee falcon]

I want to convert rgb images to lab. But above code is not working.It not shows any output after the conversion.Help me out

Answer 3

[Stalin Samuel]

lab to rgb

[somasekar jalari]

i am getting error after compile the above matalb code: ??? Error using ==> times Integers can only be combined with integers of the same class, or scalar doubles.

Error in ==> Lab2RGB at 34 fY = (~YT) .* (L / 903.3) + YT .* fY;

[somasekar jalari]

thank u