Differences

This shows you the differences between two versions of the page.

--- other:dsx:x4d:pixel_difference [2025/05/29 14:06] – Cleaned up and added headers + See Also section + links. wikisysop
+++ other:dsx:x4d:pixel_difference [2025/05/29 15:18] (current) – [Comparison Process] wikisysop
@@ Line 6: / Line 6: @@
 Each pixel in the processed [[other:dsx:dsx_definitions#digitally_reconstructed_radiograph_drr|DRR]] image is compared directly to its corresponding pixel in the X-ray image. To compare a DRR pixel to an X-ray pixel:
-  - the absolute value of the difference between them is calculated.
+  - The absolute value of the difference between them is calculated.
-  - if this difference is greater than the Difference Threshold and the DRR pixel value is greater than Bright Threshold, then the difference is squared. This gives a greater weight to DRR pixels that are bright and which do not match well with their corresponding X-ray pixels.
+  - If this difference is greater than the Difference Threshold and the DRR pixel value is greater than Bright Threshold, then the difference is squared. This gives a greater weight to DRR pixels that are bright and which do not match well with their corresponding X-ray pixels.
-  - the pixel difference is then squared and multiplied by a brightness factor. This factor is 1.0 plus Bright Factor times the DRR pixel value. When Bright Factor is zero, bright DRR pixels are not weighted differently than any others. But when it is greater than zero, the DRR’s brightness is used to weight the error for that pixel. This is a second method of weighting a bright DRR pixel more heavily, without considering its difference with the X-ray pixel (as the first method does).
+  - The pixel difference is then squared and multiplied by a brightness factor. This factor is 1.0 plus Bright Factor times the DRR pixel value. When Bright Factor is zero, bright DRR pixels are not weighted differently than any others. But when it is greater than zero, the DRR’s brightness is used to weight the error for that pixel. This is a second method of weighting a bright DRR pixel more heavily, without considering its difference with the X-ray pixel (as the first method does).
   - The values for all pixels in each view are then summed to determine the fitness for that view.
   - The sums for the two views are then multiplied to get the overall image correlation value, which the algorithm tries to minimize.