jpeg2000 compression of hyperspectral image data (imwrite not working)

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Pushkar Khatri 2019-4-7

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https://ww2.mathworks.cn/matlabcentral/answers/454913-jpeg2000-compression-of-hyperspectral-image-data-imwrite-not-working

编辑： Pushkar Khatri 2019-4-8

I am trying to apply add noise to a hyperspectral image data matrix(m-n-layers) by applying jpeg2000 compression on each of the layers saparately. So we can't use it like a nomal .jgp or .png image. I tried the imwrite scheme in loop format (not actual code here),

a = image(:,:,1); % a can only be a gray scale or rgb or an indexed data as I remember 
imwrite(a,'image1.jpg', 'Compression','jpeg','CompressionRatio',10);
% the upper line threw an error that "not valid arguments" 
% neither the next line work 
imwrite(a,'image1.jpg','Mode','lossy','CompressionRatio',10); %according to the documentation 
%the syntax doesn't allow the output to be a data matrix like the input itself too
imwrite(a,imageNoise(:,:,1), 'Compression','jpeg','CompressionRatio',10);

, but apparantely it allows compression for HDF format only. I want to store the output in a data matrix format(m-n-layers) only (compression applied layerwise). Can you suggest me any alternate way to apply jpeg2000 compression without imwrite. Thanks in advance.

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Walter Roberson 2019-4-7

'Compression' as an option is available only for HDF4 and TIFF.

'CompressionRatio' as an option is available only for JPEG2000. To get JPEG2000 you need to use the 'jp2' option (before the keyword/value pairs), or you need to use 'jp2' or 'jpx' as the file extension. JPEG2000 options are not available for .jpeg file extension.

Pushkar Khatri 2019-4-8

编辑：Pushkar Khatri 2019-4-8

在 MATLAB Online 中打开

So I ran this code

a = img(:,:,190); %190th layer
a_8Bit = uint8(255 * mat2gray(a));
imwrite(a_8bit,'imageb.jp2','CompressionRatio',10) 
%scaled the layer of image to uint8 

It worked! the output file is created as imageb.jp2 file

I have to create the modiefied img data matrix. I can't just store .jp2 files. I'll have to run this imwrite function 190 times manually. Can you suggest me an efficient way so that i can run it in one loop for all the layers(applying same compression ratio to each layer) and store in one place, then I will read the images in data matrix format?

Thanks a lot

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