How to convert 1D binary data matrix to 2D image matrix?

I have a one-dimensional matrix of size 256X256X8. It has a string of 0 and 1 of the said length. I want to form an 2D Image matrix of size 256x256 from the previous matrix with each eight bits in the original matrix representing an integer in the final matrix. Is there any way to do it?

Answer 1

[Image Analyst]

I think you have to scoot along in chunks of 8 extracting the binary bits, then use bin2dec(), something like (untested)

count = 1;
for index = 1 : 8 : 256*256*8
  substring = initialString(index:index+7);
  vector1D(count) = bin2dec(substring);
  count = count+1;
end

and then you will have a 1D decimal vector of length 256*256.

Then you have to use reshape() to form it into a 2D matrix:

matrix2D = reshape(vector1D, [256, 256]);

[Ratnakirti Roy]

This is working but if I use imshow(matrix2D) then only a white image is displayed and this is not what I intented to do.

[Walter Roberson]

Initialize:

Vector1D = zeros(256, 256, 'uint8');

and afterwards you will not even need to reshape() the matrix.

[Image Analyst]

Reason being is that if you use imshow() if the class of the array is single or double, it expects the values to be in the range 0-1. If you have floating point values in the range 0-255, almost all of them are > 1 so they show up as pure white. To get around this you either have to pass in a uint8 image, as Walter suggested, or cast it to uint8 upon calling imshow:

imshow(uint8(doubleArray));

or use [] to scale it properly:

imshow(doubleArray, []);

[Ratnakirti Roy]

Thnks....I have done the conversion already and now things are perfect....Thnks once again

Answer 2

[Azzi Abdelmalek]

[ii,jj]=find(ones(256,256));
a=randi(2,256,256,8)-1;
b=cell2mat(arrayfun(@(x,y)  a(x,y,1:8),ii,jj,'un',0)' );
out=bin2dec(num2str(reshape(b,256*256,8)));
res=zeros(256,256);
res(1:256*256)=out