X-Ray versus Light Field centres difference

In the example figures above, the witdh is vertical because the test object is rotated by 90°

From the positions of the two fields (X-Ray and Light) the differences of centres on width and height directions are calculated. The difference has a sign: positive values mean that the X-Ray field centre is on the right/lower than the light field centre.

Centres difference on width = :$CW_X - CW_L$

Centres difference on height = :$CH_X - CH_L$

where:

$CW_X$ = Centre on width of the X-Ray field

$CW_L$ = Centre on width of the light field

$CH_X$ = Centre on height of the X-Ray field

$CH_L$ = Centre on height of the light field