From 55153e634ba8771875b6dbc74604e0e09c62da5c Mon Sep 17 00:00:00 2001
From: Douglas Yau <dy@dicomserver.net>
Date: Wed, 9 Nov 2022 12:32:57 -0600
Subject: [PATCH] Fix the orthogonalization of the matrix

---
 src/lib/getImageData.js | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/lib/getImageData.js b/src/lib/getImageData.js
index b72fade2..c3cbc284 100644
--- a/src/lib/getImageData.js
+++ b/src/lib/getImageData.js
@@ -35,15 +35,12 @@ export default function getImageData(imageIds, displaySetInstanceUid) {
   const colCosineVec = vec3.fromValues(...columnCosines);
   const scanAxisNormal = vec3.cross([], rowCosineVec, colCosineVec);
 
-  let direction = [rowCosineVec, colCosineVec, scanAxisNormal];
-  vtkMath.orthogonalize3x3(direction, direction);
-
   //setDirection expects orthogonal matrix
-  const orthogonalizedDirection = [
-    ...direction[0],
-    ...direction[1],
-    ...direction[2],
-  ];
+  let direction = [];
+  vtkMath.orthogonalize3x3(
+    [rowCosineVec, colCosineVec, scanAxisNormal],
+    direction
+  );
 
   const { spacing, origin, sortedDatasets } = sortDatasetsByImagePosition(
     scanAxisNormal,
@@ -92,7 +89,7 @@ export default function getImageData(imageIds, displaySetInstanceUid) {
   const imageData = vtkImageData.newInstance();
   imageData.setDimensions(xVoxels, yVoxels, zVoxels);
   imageData.setSpacing(xSpacing, ySpacing, zSpacing);
-  imageData.setDirection(orthogonalizedDirection);
+  imageData.setDirection(direction);
   imageData.setOrigin(...origin);
   imageData.getPointData().setScalars(scalarArray);