how can I convert a double image into gray unit8 image?

Lets say that we have a 256x256 double image, how can we convert it into a 256x256 uint8?

[Khairul Bashar Syed]

Say the image matrix is im. So just use im=uint8(im);

Answer 1

[Star Strider]

I would use the uint8 function.

[Waseem AL Aqqad]

I believe that there is no such function.

What's the complete function? is it im2unit8(I)? Thanks!

[Star Strider]

The uint8 function exists (at least in the documentation). Click on the link.

An equivalent Image Processing Toolbox function is im2uint8.

[Mikhail]

Of course you can use uint8.

[Star Strider]

Thank you Mikhail, and welcome to the ranks of those of us who believe in the existence of uint8!

[Waseem AL Aqqad]

guys,

it keeps giving me this error:

??? Undefined function or method 'im2unit8' for input arguments of type 'double'.

I dunno why?

[Star Strider]

Do you have the Image Processing Toolbox?

In the Command Window type:

which im2uint8 -all

You should get as the result:

C:\Program Files\MATLAB\R2014b\toolbox\images\images\im2uint8.m
C:\Program Files\MATLAB\R2014b\toolbox\images\images\@gpuArray\im2uint8.m  % gpuArray method

with the correct directory for the version of MATLAB you are using.

[Waseem AL Aqqad]

I got this result:

C:\Users\KUWA2002\Desktop\MATLAB_portable\R2010b\toolbox\curvefit\cftoolgui\private\im2uint8.m % Private to cftoolgui C:\Users\KUWA2002\Desktop\MATLAB_portable\R2010b\toolbox\images\images\im2uint8.m

[Star Strider]

It seems you have the Image Processing Toolbox and im2uint8. (I don’t know what it’s doing in the Curve Fitting Toolbox, but since I don’t have the CFT, I won’t comment further.) You should be able to use it since it’s in your MATLAB search path.

If im2uint8 won’t work for you for whatever reason, see if uint8 will produce an acceptable result.

(I am certain uint8 exists. I saw its footprints in the garden and strands of its fur snagged on the hedge!)

[Star Strider]

Yes. Use uint8 and see if it does what you want.

[Star Strider]

Actually, very few of us here are MathWorks employees. Most of us (including me) are unpaid volunteers who do our individual and collective best to share what we know.

If you cannot get im2unit8 or uint8 working, contact MathWorks Tech Support to see if they can figure out what the problem is.

[Star Strider]

My pleasure!

I wish we could have gotten im2uint8 or uint8 working for you.

Answer 2

[Image Analyst]

There is no function 'im2unit8' but there is a function im2uint8. It matters how you spell it and you spelled it incorrectly. I never use it - I use uint8(). im2uint8() also does scaling, of course you could use uint8(mat2gray()) to scale it to the full range.

[Star Strider]

I misspelled it in my last Comment but not earlier. Waseem has it in his MATLAB search path but apparently can’t use it or uint8.

That seems to be the problem.

[Star Strider]

Waseem — You spelled it correctly earlier in this thread. However we did not see your code, so I assumed you simply misspelled it in your Question.