Picket fence-- can't detect central picket

[Alistair Templeton]

I've been running through the options forcing the number of pickets, the spacing, the detection style, and the peak threshold and I can't seem to be able to find the central picket. Instead, it finds the 15 mm picket twice.

I've attached the image, which was created with an arc-based picket fence delivery.  Looking at numerical profiles across the image I don't see anything strange. Any generous souls want to give it a whirl?

[tbe...@gmail.com]

Hi,

I was able to get reasonable results for your dcm when using the filter option:

mypf = PicketFence(r'c:\temp\pf_test.dcm', filter=2)

I am not exactly sure how this influences your results.

regards

Thomas

[Alistair Templeton]

Thanks! It looks to change the detected picket location by about 0.1-0.2 mm. Not zero, but much smaller than reasonable tolerances.  This was using Varian's downloadable rapidarc QA .dcm which uses super narrow 1mm spacing.  I'm giving it a whirl with a modified one of 2mm spacing.