WinstonLutz error analysis

[taconi23]

Hello. I'm using the lastest version of Pylinac. The problem is when analized a image from winstonlutz many times the same image. The cax and BB position in axis X is correct and show same value all times but in axis Y the value change alternatively

the code to reproduce the behavior is:

from pylinac import WinstonLutz

dir = 'imagenes/31012020'

wl = WinstonLutz(dir) wl0 = wl.images[0] wl0.analyze() print(f'cax_x: {wl0.field_cax.x}, cax_y: {wl0.field_cax.y}') wl0.analyze() print(f'cax_x: {wl0.field_cax.x}, cax_y: {wl0.field_cax.y}') wl0.analyze() print(f'cax_x: {wl0.field_cax.x}, cax_y: {wl0.field_cax.y}') wl0.analyze() print(f'cax_x: {wl0.field_cax.x}, cax_y: {wl0.field_cax.y}')

the results obtained are:

cax_x: 572.3557522123893, cax_y: 571.5522123893805 cax_x: 572.3557522123893, cax_y: 573.4477876106195 cax_x: 572.3557522123893, cax_y: 571.5522123893805 cax_x: 572.3557522123893, cax_y: 573.4477876106195

How we can see the component in axis Y change. this is correct?. Thanks