Fix inverse projection

Author: eigenvivek

diffdrr/drr.py

@@ -283,9 +283,9 @@ def inverse_projection(
     pts: torch.Tensor,
 ):
     """Backproject points in pixel plane (2D) onto the image plane in world coordinates (3D)."""
-    # pts = pts.flip(-1)
+    pts[..., 1] = self.detector.height - pts[..., 1]
     if self.detector.reverse_x_axis:
-        pts[..., 1] = self.detector.width - pts[..., 1]
+        pts[..., 0] = self.detector.width - pts[..., 0]
     x = self.detector.sdd * torch.einsum(
         "ij, bnj -> bni",
         self.detector.intrinsic.inverse(),

notebooks/api/00_drr.ipynb

@@ -434,9 +434,9 @@
     "    pts: torch.Tensor,\n",
     "):\n",
     "    \"\"\"Backproject points in pixel plane (2D) onto the image plane in world coordinates (3D).\"\"\"\n",
-    "    # pts = pts.flip(-1)\n",
+    "    pts[..., 1] = self.detector.height - pts[..., 1]\n",
     "    if self.detector.reverse_x_axis:\n",
-    "        pts[..., 1] = self.detector.width - pts[..., 1]\n",
+    "        pts[..., 0] = self.detector.width - pts[..., 0]\n",
     "    x = self.detector.sdd * torch.einsum(\n",
     "        \"ij, bnj -> bni\",\n",
     "        self.detector.intrinsic.inverse(),\n",