js-dicom/src/ImageUtility/metaData/getLUTs.js

this is js-dicom

function getLUT (pixelRepresentation, lutDataSet) {
    let numLUTEntries = lutDataSet.uint16('x00283002', 0);

    if (numLUTEntries === 0) {
        numLUTEntries = 65535;
    }
    let firstValueMapped = 0;

    if (pixelRepresentation === 0) {
        firstValueMapped = lutDataSet.uint16('x00283002', 1);
    } else {
        firstValueMapped = lutDataSet.int16('x00283002', 1);
    }
    const numBitsPerEntry = lutDataSet.uint16('x00283002', 2);
    // console.log('LUT(', numLUTEntries, ',', firstValueMapped, ',', numBitsPerEntry, ')');
    const lut = {
        id: '1',
        firstValueMapped,
        numBitsPerEntry,
        lut: []
    };

    // console.log("minValue=", minValue, "; maxValue=", maxValue);
    for (let i = 0; i < numLUTEntries; i++) {
        if (pixelRepresentation === 0) {
            lut.lut[i] = lutDataSet.uint16('x00283006', i);
        } else {
            lut.lut[i] = lutDataSet.int16('x00283006', i);
        }
    }

    return lut;
}


function getLUTs (pixelRepresentation, lutSequence) {
    if (!lutSequence || !lutSequence.items.length) {
        return;
    }
    const luts = [];

    for (let i = 0; i < lutSequence.items.length; i++) {
        const lutDataSet = lutSequence.items[i].dataSet;
        const lut = getLUT(pixelRepresentation, lutDataSet);

        if (lut) {
            luts.push(lut);
        }
    }

    return luts;
}

export default getLUTs;