Optimierung der Eigenschaften des Medipix2-Detektors bezüglich energieaufgelöster Röntgenbildgebung Frank Nachtrab 13. 03. 2006Three translation stages
(1 µm resolution)
One rotation stage
(0.1 degree resolution)
translation
stages
Frank Nachtrab
Physikalisches Institut Universität Erlangen-Nürnberg
Ring artefacts in CT
Problem: variations in lower threshold lead to differing counting behavior for every pixel (‘gain’)
→ ring artefacts in computed tomography
Frank Nachtrab
Equalisation using
electronic noise
flatfield images
- spectrum not taken into acount - optimised for THL of noise - only electronic properties - time ~ hours
+ optimised for given spectrum + optimised for given THL + sensor inhomogenities considered + rather fast method
Frank Nachtrab
→ calculate width and distance of distributions
Frank Nachtrab
→ OptimumTHS (for each Chip on the Quad!)
Frank Nachtrab
(lower is better; zero for a perfect detector)
Sigma = std. deviation
Sigma^2 = variance
Flatfieldmasks better by a factor of ~ 1.35
Frank Nachtrab
→ quadratic fit?
tune FBK settings after generation of mask for better global homogeneity
automate procedure → Pixelman plugin?