CODEWITHSUNDEEP
matlabmatrix
maximusdooku
maximusdooku

Reputation: 5512

How can I imwrite a double in Matlab?

I am producing 3500x7500 size double matrices in a loop that I want to export as tif files.

A section of the code

for k = 1:length(basinlist{1})
    #some operation that produces GRID
    imwrite(GRID,filename);
end

But, when I do this, the TIF file produced contains only 255 and output is in uint8. I read about it in the documentation, but I am not able to fix it. All I want is to retain the original values with no scaling or anything.

If this helps:

>> max(max(GRID))

ans =

   1.5646e+04

>> min(min(GRID))

ans =

   1.1119e+03

Upvotes: 1

Views: 952

Answers (1)

Crowley
Crowley

Reputation: 2331

Suppose we want to create image with such colour depth that will fit to given data.

Data exported to image format are converted to uint8 by default (data range 0-2^8-1).

But Matlab (2011b) can operate with more uintX formats where X stands for X bits per value.

  • uint8 with span 0-255 (2^8)
  • uint16 with span 0-65 535 (2^16)
  • uint32 with span 0-4.29 e 9 (2^32)
  • uint64 with span 0-1.84 e 19 (2^64)

Code to export data without any loss:

for k = 1:length(basinlist{1})
  #some operation that produces GRID

  %% Convert GRID to roughest acceptable uint format
  GRID=uint16(GRID);

  %% Export
  imwrite(GRID,filename);
end

Upvotes: 1

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