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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 | import type { Types } from '@cornerstonejs/core';
import { parseAffineMatrix } from './affineUtilities';
/**
* This converts scalar data: LPS to RAS and RAS to LPS
*/
const invertDataPerFrame = (dimensions, imageDataArray) => {
let TypedArrayConstructor;
let bytesPerVoxel;
if (
imageDataArray instanceof Uint8Array ||
imageDataArray instanceof ArrayBuffer
) {
TypedArrayConstructor = Uint8Array;
bytesPerVoxel = 1;
} else if (imageDataArray instanceof Int16Array) {
TypedArrayConstructor = Int16Array;
bytesPerVoxel = 2;
} else if (imageDataArray instanceof Float32Array) {
TypedArrayConstructor = Float32Array;
bytesPerVoxel = 4;
} else {
throw new Error(
'imageDataArray needs to be a Uint8Array, Int16Array or Float32Array.'
);
}
// Make a copy of the data first using the browser native fast TypedArray.set().
const newImageDataArray = new TypedArrayConstructor(
imageDataArray.byteLength
);
const view = new TypedArrayConstructor(imageDataArray);
newImageDataArray.set(view);
// In order to switch from LP to RA within each slice, we just need to reverse each section.
// We can do this in place using web api which is very fast, by taking views on different parts of a single buffer.
const numFrames = dimensions[2];
const frameLength = dimensions[0] * dimensions[1];
const buffer = newImageDataArray.buffer;
for (let frame = 0; frame < numFrames; frame++) {
const byteOffset = frameLength * frame * bytesPerVoxel;
// Get view of underlying buffer for this frame.
const frameView = new TypedArrayConstructor(
buffer,
byteOffset,
frameLength
);
frameView.reverse();
}
return newImageDataArray;
};
function rasToLps(niftiHeader) {
const { affine } = niftiHeader;
// RAS
const { orientation, origin, spacing } = parseAffineMatrix(affine);
// LPS
const newOrigin = [-origin[0], -origin[1], origin[2]] as Types.Point3;
// Change row-major to column-major for LPS orientation
const newOrientation = [
-orientation[0],
-orientation[3],
orientation[6],
-orientation[1],
-orientation[4],
orientation[7],
-orientation[2],
-orientation[5],
orientation[8],
];
return {
origin: newOrigin,
orientation: newOrientation,
spacing,
};
}
function lpsToRas(header) {
const { origin, orientation, spacing, dimensions, dataType } = header;
const newOrigin = [-origin[0], -origin[1], origin[2]];
const newOrientation = [
-orientation[0],
-orientation[3],
orientation[6],
-orientation[1],
-orientation[4],
orientation[7],
-orientation[2],
-orientation[5],
orientation[8],
];
return {
orientation: newOrientation,
origin: [newOrigin[0], newOrigin[1], newOrigin[2]],
dataType,
dimensions,
spacing,
slope: header.slope,
inter: header.inter,
max: header.max,
min: header.min,
};
}
export { lpsToRas, rasToLps, invertDataPerFrame };
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