Problems reading .RAW file

Hello

I have a strange problem when trying to read in a grayscale image of 12bit. there are always strange gray background when I am trying to load them in Matlab. I wish only black background and white cross.

this is image with strange grey background

this is the image I wish

Do you know what may be the reason for such a problem ?

Thanks in advance

my code

fid=fopen('image.dat','rt');

q2=fread(fid,[3840 2160],'*ubit12');

q10=uint16(q2');

fclose(fid);

[Jan]

Why do you open the file in text mode? '*ubit12' should reply a UINT16 already, so you do not need the conversion.

Can you provide an example file?

[Xie Yiru]

which mode should I use to open the image file? I see a example, they use this mode. But I don't know where come the gray noisy.

Yes I can give you the raw file

https://drive.google.com/open?id=1FD0gURfxYR7IPCAn11lKKmI2o7RNP4-P

[Walter Roberson]

It is common to pack 12 bits into 2 bytes and leave the other 4 bits 0, which would be a uint16 format instead of a ubit12 format.

[Xie Yiru]

yes i have tried. But I still get the image like the first one with grey background. Can you maybe try one time and tell me the code. I have raw File linkes

https://drive.google.com/open?id=1FD0gURfxYR7IPCAn11lKKmI2o7RNP4-P

[Jan]

@Xie Yiru: "which mode should I use to open the image file?" - See Guillaume's answer: Without the 't' in fopen.

Answer 1

[Guillaume]

Your image is read incorrectly because you specified 't' in the fopen call. 't' means text mode and will replace some bytes sequences (specifically \r\n) by a different one (\r), which is certainly not what you want.

Without it, your image is read properly

fid = fopen('image.dat');  %you don't even need to specify 'r' since it's the default
q2 = fread(fid, [3840, 2160], '*ubit12');
fclose(fid);
imshow(q2, []);

[Walter Roberson]

Oh, good catch!