Image readout and correction.



next up previous contents index
Next: Sources of error Up: Image plate detector. Previous: The image plate

Image readout and correction.

After exposure the stored image is read-out using red He-Ne laser light. The laser light induces PSL in the phosphor which in turn emits characteristic blue light, the intensity of which is proportional to the number of absorbed incident X-ray photons. The luminescence is detected by a photomultiplier tube and then converted to a digital signal.

The raw spiral image is then corrected against a calibration image and converted to a Cartesian coordinate system. A separate calibration image is set up for each plate using a flood field from an radioactive source and is used to correct all images recorded by the plates. After read out the plate is erased more thoroughly by Tungsten lamps.



Gwyndaf Evans
Fri Oct 7 15:42:16 MET 1994