Leeds TO _is_counterclockwise causing unrequired flip

[callumgillies]

Describe the bug Leeds Test Object image if flipped unnecessarily. Results are then incorrect

To Reproduce Steps to reproduce the behavior: Import attached image of Leeds Test Object and plot_analyzed_image (Unable to upload as dcm so uploaded as jpg. Can supply dcm if required)

Expected behavior I expect the analyze function "_is_counterclockwise" to return false, but it doesn't. The image is flipped for the analysis which causes the low contrast ROIs to be reversed and the MTF ROIs to be incorrectly placed.

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Additional context Add any other context about the problem here.

[jrkerns]

Have you tried forcing inversion? .analyze(..., invert=True). This might help. https://pylinac.readthedocs.io/en/latest/planar_imaging.html#troubleshooting

[callumgillies]

I think the problem is the "flip" rather than the "inversion"? - for some reason the "_is_counter_clockwise" function is not not working for any images we are acquiring. Please find attached the result if I set invert to True, I didn't know if there was a way I could force flip/noflip using the library as is?

[jrkerns]

I see some artifacting on the top of the image. If that's true, it would be worth it to crop the image a bit first. Edge artifacts are the # 1 reason for failure of analysis.

You can crop like so:

leeds = pylinac.LeedsTOR(...)
leeds.image.crop(pixels=5)
leeds.analyze(...)

If that doesn't work, then the last resort is a hack to override the method:

class MyLeeds(LeedsTOR):

     def _is_counter_clockwise(self):
              return True  # or false, whatever you need

leeds = MyLeeds(...)
leeds.analyze(...)

[jrkerns]

Assuming resolved.