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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 | 128x 128x 128x 128x 128x 128x 128x 128x 128x 128x 12x 12x 12x 116x 116x 116x 116x | import type { DataSet } from 'dicom-parser';
import unpackBinaryFrame from './unpackBinaryFrame';
/**
* Function to deal with extracting an image frame from an encapsulated data set.
*/
function getUncompressedImageFrame(
dataSet: DataSet,
frameIndex: number
): Uint8Array {
const pixelDataElement =
dataSet.elements.x7fe00010 || dataSet.elements.x7fe00008;
const bitsAllocated = dataSet.uint16('x00280100');
const rows = dataSet.uint16('x00280010');
const columns = dataSet.uint16('x00280011');
let samplesPerPixel = dataSet.uint16('x00280002');
/**
* From: http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.7.6.3.html
*
* Though the chrominance channels are downsampled, there are still nominally
* three channels, hence Samples per Pixel (0028,0002) has a value of 3, not
* 2. I.e., for pixel data in a Native (uncompressed) format, the Value Length
* of Pixel Data (7FE0,0010) is not:
*
* Rows (0028,0010) * Columns (0028,0011) * Number of Frames (0028,0008) *
* Samples per Pixel (0028,0002) * (⌊(Bits Allocated (0028,0100)-1)/8⌋+1)
*
* padded to an even length, as it would otherwise be, but rather is:
*
* Rows (0028,0010) * Columns (0028,0011) * Number of Frames (0028,0008) * 2 *
* (⌊(Bits Allocated (0028,0100)-1)/8⌋+1)
*
* padded to an even length.
*/
const photometricInterpretation = dataSet.string('x00280004');
Iif (photometricInterpretation === 'YBR_FULL_422') {
samplesPerPixel = 2;
console.warn(
`Using SamplesPerPixel of 2 for YBR_FULL_422 photometric interpretation.
See http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.7.6.3.html for more information.`
);
}
const pixelDataOffset = pixelDataElement.dataOffset;
const pixelsPerFrame = rows * columns * samplesPerPixel;
let frameOffset;
if (bitsAllocated === 8) {
frameOffset = pixelDataOffset + frameIndex * pixelsPerFrame;
Iif (frameOffset >= dataSet.byteArray.length) {
throw new Error('frame exceeds size of pixelData');
}
return new Uint8Array(
dataSet.byteArray.buffer.slice(frameOffset, frameOffset + pixelsPerFrame)
);
} else if (bitsAllocated === 16) {
frameOffset = pixelDataOffset + frameIndex * pixelsPerFrame * 2;
Iif (frameOffset >= dataSet.byteArray.length) {
throw new Error('frame exceeds size of pixelData');
}
return new Uint8Array(
dataSet.byteArray.buffer.slice(
frameOffset,
frameOffset + pixelsPerFrame * 2
)
);
} else Eif (bitsAllocated === 1) {
frameOffset = pixelDataOffset + frameIndex * pixelsPerFrame * 0.125;
if (frameOffset >= dataSet.byteArray.length) {
throw new Error('frame exceeds size of pixelData');
}
return unpackBinaryFrame(dataSet.byteArray, frameOffset, pixelsPerFrame);
} else if (bitsAllocated === 32) {
frameOffset = pixelDataOffset + frameIndex * pixelsPerFrame * 4;
if (frameOffset >= dataSet.byteArray.length) {
throw new Error('frame exceeds size of pixelData');
}
return new Uint8Array(
dataSet.byteArray.buffer.slice(
frameOffset,
frameOffset + pixelsPerFrame * 4
)
);
}
throw new Error('unsupported pixel format');
}
export default getUncompressedImageFrame;
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