Hello,

I've got a problem. I have JPEG Lossless images with 16 bit precision and 1 component (your library and the DICOM information tells me that)

    try {
        //read in test
        FileInputStream inStream = new FileInputStream("test0.pixeldata");
        int avaibleBytes = inStream.available();
        byte[] data = new byte[avaibleBytes];
        inStream.read(data);
        //create decoder here
        JPEGLosslessDecoder decoder = new JPEGLosslessDecoder(data);
        int[][] decoded = decoder.decode();

        // added getFrameHeader in JPEGLosslessDecoder for this prints here
        FrameHeader header = decoder.getFrameHeader();
        System.out.println("Components: " + header.getNumComponents());
        System.out.println("Precision : " + header.getPrecision());


        int min = Integer.MAX_VALUE;
        int max = Integer.MIN_VALUE;
        for(int i = 0; i < decoded[0].length; i++){
            if(min > decoded[0][i]){
                min = decoded[0][i];
            }
            if(max < decoded[0][i]){
                max = decoded[0][i];
            }
        }
        System.out.println("Max value: " + max);
        System.out.println("Min value: " + min);


    } catch(Exception ex){
        ex.printStackTrace();
    }

The console output is:
Components: 1
Precision : 16
Max value: 67007
Min value: 63536

Why does some values exceeds the range of 16 bit precision? I assumed that the values could be wrapped safely by an Java short.

I attached you the image stream from a DICOM file saved to an .pixeldata - file in a .zip.

Best regards & Thanks
Hermann

test0.pixeldata.zip

Hallo,

nice library. After a couple of hours searched i found this library to decode JPEG Lossless files. My task was to do a own implementation for JPEG Lossless parsing for DICOM files. This code should be contributed to the "TwelveMonkeys" ImageLibrary, which we use in our DICOM Software.
(Github Link for "TwelveMonkeys")

Maybe there is a possibility to integrate your Code into the "TwelveMonkeys" Project? If you want, I can do the implementation. I know you use the MIT license, but i wanted to hear, if its okay for you.

Best regards
Hermann

Hi. Firstly, thank so much for writing this. I'm writing a DICOM parser in a different language (Xojo) and, like many people, managed to read the elements in the DICOM file and be able to generate an image if the PixelData was uncompressed but have struggled to decode lossless JPEG.

I'm attempting to port this Java library to Xojo. I have one question. In the readme it says:

// single component
int[] decompressedData = decoder.decode()[0];

The bytes in decompressedData what format are they? Can I consider them the same as if they were in DICOM's "uncompressed" format. I.e I just need to apply RescaleSlope and RescaleIntercept and windowing to them or have they been decoded to a different JPEG format?