Point Spread Function Estimation of Image Intensifier Tubes

Point Spread Function Estimation and Uncertainty Quantification

“…Calibration objects typically have simple geometry and reduce the complexity of solving the deconvolution problem in (1.7). For example, the object could be a circular aperture or two perpendicular edges aligned with the imaging plane [Doering et al, 1992;Watson, 1993]. As will be seen, the additional assump-tion of radial symmetry on k is sufficient to estimate the PSF from the calibration image of a straight edge.…”

“…A system that is not biased with respect to spatial orientation is said to exhibit isotropic blur, so that, in the convolution model, the PSF is radially symmetric. In fact, many parametrically modeled PSFs assume radially symmetry [Doering et al, 1992;Jain, 1989;Kundur and Hatzinakos, 1996;Watson, 1993].…”

Three-dimensional flaw reconstruction using a real-time X-ray imaging system

“…The optical knife edge-based measurement for Xray systems is implemented using the edge of a lead plate. The primary drawback of this method is undersampling in the edge transition region, where only 5 to 10 pixel values are available to characterize the edge (Doering, Gray, and Basart, 1992). Reichenbach, Park, and Narayanswamy (1991) apply a more sophisticated ap proach to CCD characterization where the knife-edge is positioned at a very slight angle with respect to the row of pixels.…”

Deconvolution of the point spread function of an x-ray image intensifier

“…Obviously, there is some amount of noise in the measurement procedure and this noise is further enhanced when the step function response is numerically differentiated to get the impulse function response. But, the main drawback of this method is the undersampling in the edge transition region where only 5 to 10 pixel values are available to characterize the edge (Doering, Gray and Basart, 1992). So a different technique developed by Glasser, Valliant and Chazallet (1988), where the output of a single pixel is monitored while the knife-edge is shifted in sub-pixel increments, was implemented.…”