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

this is js-dicom

function getLutDescriptor (dataSet, tag) {
    if (!dataSet.elements[tag] || dataSet.elements[tag].length !== 6) {
        return;
    }

    return [dataSet.uint16(tag, 0), dataSet.uint16(tag, 1), dataSet.uint16(tag, 2)];
}

function getLutData (lutDataSet, tag, lutDescriptor) {
    const lut = [];
    const lutData = lutDataSet.elements[tag];
    const numLutEntries = lutDescriptor[0];

    for (let i = 0; i < numLutEntries; i++) {
        // Output range is always unsigned
        if (lutDescriptor[2] === 16) {
            lut[i] = lutDataSet.uint16(tag, i);
        } else {
            lut[i] = lutDataSet.byteArray[i + lutData.dataOffset];
        }
    }

    return lut;
}

function populatePaletteColorLut (dataSet, imagePixelModule) {
    // return immediately if no palette lut elements
    if (!dataSet.elements.x00281101) {
        return;
    }
    imagePixelModule.redPaletteColorLookupTableDescriptor = getLutDescriptor(dataSet, 'x00281101');
    imagePixelModule.greenPaletteColorLookupTableDescriptor = getLutDescriptor(dataSet, 'x00281102');
    imagePixelModule.bluePaletteColorLookupTableDescriptor = getLutDescriptor(dataSet, 'x00281103');

    imagePixelModule.redPaletteColorLookupTableData = getLutData(dataSet, 'x00281201', imagePixelModule.redPaletteColorLookupTableDescriptor);
    imagePixelModule.greenPaletteColorLookupTableData = getLutData(dataSet, 'x00281202', imagePixelModule.greenPaletteColorLookupTableDescriptor);
    imagePixelModule.bluePaletteColorLookupTableData = getLutData(dataSet, 'x00281203', imagePixelModule.bluePaletteColorLookupTableDescriptor);
}

function populateSmallestLargestPixelValues (dataSet, imagePixelModule) {
    const pixelRepresentation = dataSet.uint16('x00280103');

    if (pixelRepresentation === 0) {
        imagePixelModule.smallestPixelValue = dataSet.uint16('x00280106');
        imagePixelModule.largestPixelValue = dataSet.uint16('x00280107');
    } else {
        imagePixelModule.smallestPixelValue = dataSet.int16('x00280106');
        imagePixelModule.largestPixelValue = dataSet.int16('x00280107');
    }
}

function getImagePixelModule (dataSet) {

    const imagePixelModule = {
        samplesPerPixel: dataSet.uint16('x00280002'),
        photometricInterpretation: dataSet.string('x00280004'),
        rows: dataSet.uint16('x00280010'),
        columns: dataSet.uint16('x00280011'),
        bitsAllocated: dataSet.uint16('x00280100'),
        bitsStored: dataSet.uint16('x00280101'),
        highBit: dataSet.uint16('x00280102'),
        pixelRepresentation: dataSet.uint16('x00280103'),
        planarConfiguration: dataSet.uint16('x00280006'),
        pixelAspectRatio: dataSet.string('x00280034')
    };

    populateSmallestLargestPixelValues(dataSet, imagePixelModule);
    populatePaletteColorLut(dataSet, imagePixelModule);

    return imagePixelModule;

}

export default getImagePixelModule;