How to save a Tiff using signed values with LibTiff library.

I am using the LibTiff library, as I already know that imwrite can't deal with signed values. If I try to convert FinalImage to int16 before saving it, I get the following error message:

Error using tifflib If SampleFormat is Uint, the image datatype is restricted to one of the following: logical, uint8, uint16, uint32.

Error in Tiff/writeAllStrips (line 1933) tifflib('writeEncodedStrip',obj.FileID, stripNum-1,imageData(row_inds,:));

Error in Tiff/write (line 1459) obj.writeAllStrips(varargin{:});

Error in tiffsaveexample (line 33) t.write(intFinalImage(:,:,1));

So it seems that I must change this variable SampleFormat, but I don't know how to modify this. Any recommendations?

This results from the follwing code:

% Save tiff unsigned attempt
FileTif='11_7_blank1_avgentire_stack_bck.tif';
    InfoImage=imfinfo(FileTif);
    mImage=InfoImage(1).Width;
    nImage=InfoImage(1).Height;
    NumberImages=length(InfoImage);
    FinalImage=zeros(nImage,mImage,NumberImages,'uint16');

    TifLink = Tiff(FileTif, 'r');
    for i=1:NumberImages
        TifLink.setDirectory(i);
        FinalImage(:,:,i)=TifLink.read();
    end
    TifLink.close();

    intFinalImage = int16(FinalImage);

     tiffFile = strcat('bksub2_', FileTif);

     t = Tiff(tiffFile,'w')
            tagstruct.ImageLength = size(intFinalImage,1);
            tagstruct.ImageWidth = size(intFinalImage,2);
            tagstruct.Photometric = Tiff.Photometric.MinIsBlack;
            tagstruct.BitsPerSample = 16;
            tagstruct.SamplesPerPixel = 1;
            tagstruct.RowsPerStrip = 16;
            tagstruct.PlanarConfiguration = Tiff.PlanarConfiguration.Chunky
            tagstruct.Software = 'MATLAB'
            t.setTag(tagstruct)

            t.write(intFinalImage(:,:,1));
            t.close();

Answer 1

[Ashish Uthama]

You need one extra tag:

intFinalImage = int16(magic(10));
tiffFile = 't.tif';

t = Tiff(tiffFile,'w');
%-----------------------------------------------
tagstruct.SampleFormat = Tiff.SampleFormat.Int;
%-----------------------------------------------
tagstruct.ImageLength = size(intFinalImage,1);
tagstruct.ImageWidth = size(intFinalImage,2);
tagstruct.Photometric = Tiff.Photometric.MinIsBlack;
tagstruct.BitsPerSample = 16;
tagstruct.SamplesPerPixel = 1;
tagstruct.RowsPerStrip = 16;
tagstruct.PlanarConfiguration = Tiff.PlanarConfiguration.Chunky;
tagstruct.Software = 'MATLAB';
t.setTag(tagstruct)
t.write(intFinalImage(:,:,1));
t.close();
d = imread(tiffFile);
class(d)

ans =

int16

[Katherine]

This fixes it! Thank you so much for your help!