Here is the formula I learned in x-ray school ... Penumbra = FS x OID / SOD. Units inches or cm or mm depending on problem. FS = Focal spot size, OID - Object Image Distance, SOD - Source to Object Distance.... OID + SOD = SID ... conversion factors to know 1 inch = 2.54 cm. 1 cm = 10 mm ... so ex. 2 mm is the same as 0.2 cm
I'm not sure this is a great way to understand the idea conceptually. The "Thickness" part is misleading. This implies an object of given thickness resting on a receptor, from which you then consider the geometric uncertainty of the edge of the entrance surface of the object as recorded on the image. If the object were not resting on the receptor, the object would have the same thickness but now there will be an additional distance to consider. I think the concept may be clearer (no pun intended) if Object to Image Distance (or some variant) instead of "thickness". It might also be easier to take the approach of similar triangles, the ratio of unsharpness to focal spot size will be equal to the ratio of the distances.
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I seem to understand it better after I hear you explain it. Thank you for posting these videos.
Very nice Joe, thank you. Jim
Here is the formula I learned in x-ray school ... Penumbra = FS x OID / SOD. Units inches or cm or mm depending on problem. FS = Focal spot size, OID - Object Image Distance, SOD - Source to Object Distance.... OID + SOD = SID ... conversion factors to know 1 inch = 2.54 cm. 1 cm = 10 mm ... so ex. 2 mm is the same as 0.2 cm
🥰😍
Thanks for uploading this
Good day Joe.
Do you know the BS EN code that this is in?
Thankssss
I'm not sure this is a great way to understand the idea conceptually. The "Thickness" part is misleading. This implies an object of given thickness resting on a receptor, from which you then consider the geometric uncertainty of the edge of the entrance surface of the object as recorded on the image. If the object were not resting on the receptor, the object would have the same thickness but now there will be an additional distance to consider. I think the concept may be clearer (no pun intended) if Object to Image Distance (or some variant) instead of "thickness". It might also be easier to take the approach of similar triangles, the ratio of unsharpness to focal spot size will be equal to the ratio of the distances.
ozmetalfan666 yea agree with u, how about at DWDI and DWSI, there will be changing in the formula, T actually represent IQI placment
Thanks a lot sir
Acha hai