How can I change phase image to gray code?

name = ['C:\Users\User\Desktop\trail.jpg'];
im = imread(name); im = im(:,:,2);
im= im2double(im);
imbin = imbinarize(im);
imbin = qammod(imbin,4,'gray');  %this part doesn't work

I tried to use function bin2gray, but it didn't work anymore. Any other alternatives failed me. My only option is doing it mannualy by if but I know this is reallby bad solutions for this problem. (30 000 000 iterations).

This is theoretical scheme how to do it. I have 6 images with fringes.

My error log

Error using qammod
Expected input number 1, X, to be one of these types:

double, single, uint8, uint16, uint32, uint64, int8, int16, int32, int64

Instead its type was logical.

Error in qammod>validateInput (line 262)
            validateattributes(x, {'numeric'}, {'real','integer','>=',0,'<',M}, mfilename, 'X', 1);

Error in qammod (line 94)
    validateInput(x, M, bitInput, outputDataType);

Error in zad2 (line 24)
    imbin = qammod(imbin,4,'gray');
 

[Image Analyst]

Then attach your data and code to read it in with the paperclip icon after you read this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

[Lukasz Sarnacki]

I have added it. Can you help me now?

[Image Analyst]

No. Maybe someone else can. I don't have the Communications toolbox that qammod is in.