CODEWITHSUNDEEP
matlabdicom
Simplicity
Simplicity

Reputation: 48966

Saving a DICOM image in PNG format

I have a dicom image which I read in matlab as:

I=dicomread('xyz.dcm');

In displaying it, I used the following command:

imshow(I,[])

What I want to ask about is, how can I write it through imwrite, such that I get the image as seen using the above imshow command?

I for instance tried this:

imwrite(I,'xyz.png','png');

but, get a dark image.

Any ideas on that?

Thanks.

Upvotes: 2

Views: 2924

Answers (3)

NinjasAtWork
NinjasAtWork

Reputation: 71

Hey I had the same problem and it seems that one of the solutions is very simple. Just check whether you are passing a string as filenames for the destination file.

I was passing the output of the fullfile function (this one outputs a cell). What happens it that imwrite function parces the inputs (vargins) and looks for the first variable with char type. It uses this index to find the argument that specifies the datatype and consequently define the colormap. If your file path is a cell, it will get the wrong index and output strange errors.

I hope this helps

Upvotes: 1

Shai
Shai

Reputation: 114926

It seems like dicom image has a 16-bit depth, which is larger than the usual 8-bit.
To verify that this is indeed the case type

>> class( I )

I would expect the output to be uint16.
If so, try:

imwrite( I, 'xyz.png', 'bitdepth', 16 );

Upvotes: 2

Shaun314
Shaun314

Reputation: 3461

When you read the image, get the colormap as well

[I, map]=dicomread('xyz.dcm');

Now when you save it, give imwrite the colormap also.

imwrite(I,map,'xyz.png','png');

And by the way, the last png isn't necessary usually. MATLAB will see the .png extension and know to save it as a png.

Upvotes: 1

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