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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 | import { vec3 } from 'gl-matrix';
/**
* Get the plane (orientation) to which the ImageOrientationPatient is most closely aligned
*
* @param displaySetService
* @param displaySetInstanceUID
* @returns orientation
*/
export default function getClosestOrientationFromIOP(displaySetService, displaySetInstanceUID) {
const displaySet = displaySetService.getDisplaySetByUID(displaySetInstanceUID);
const imageOrientationPatient = displaySet.instances[0].ImageOrientationPatient as Array<number>;
// ImageOrientationPatient must be an array of length 6.
Iif (imageOrientationPatient?.length !== 6) {
return;
}
// Take cross product to get vector coming "out" of image plane
const rowCosineVec = vec3.fromValues(
imageOrientationPatient[0],
imageOrientationPatient[1],
imageOrientationPatient[2]
);
const colCosineVec = vec3.fromValues(
imageOrientationPatient[3],
imageOrientationPatient[4],
imageOrientationPatient[5]
);
const scanAxisNormal = vec3.cross(vec3.create(), rowCosineVec, colCosineVec);
// Define the reference vectors for axial, coronal, and sagittal planes
const unitVectors = {
axial: vec3.fromValues(0, 0, 1),
coronal: vec3.fromValues(0, 1, 0),
sagittal: vec3.fromValues(1, 0, 0),
};
// Compute dot products for each reference plane
// Because all vectors are normalized, dot product is bounded between -1 and 1
let maxDot = 0;
let maxOrientation: string = '';
for (const [k, v] of Object.entries(unitVectors)) {
// Absolute value of dot product because we only care about alignment with the axis
// For example, dot product of -1 for a given axis means perfect alignment
// but the image is pointing in the "opposite" direction
const res = Math.abs(vec3.dot(scanAxisNormal, v));
Iif (res > maxDot) {
maxDot = res;
maxOrientation = k;
}
}
return maxOrientation;
}
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