CAD-based x-ray CT calibration and error compensation

Robust Frame Based X-ray Ct Reconstruction

As X-ray computed tomography (CT) is widely used in diagnosis and radiotherapy, it is important to reduce the radiation dose as low as reasonably achievable. For this purpose, one may use the TV based methods or wavelet frame based methods to reconstruct high quality images from reduced number of projections. Furthermore, by using the interior tomography scheme which only illuminates a region-o...

Gamma Calibration and Phase Error Compensation for Phase Shifting Profilometry

Phase Shifting Profilometry is a method of structured light whose three-dimensional reconstructions are susceptible to error from Gamma distortion. In practice, the luminance nonlinearity caused by the Gamma distortion effect of a digital video projector and a digital camera yields undesired fringe intensity changes, which substantially reduce the measurement accuracy, and while the effects of ...

Artifacts in X-ray CT

Phase contrast in laboratory-based X-ray CT

When scanning weakly attenuating samples using an X-ray tube with a very small focal spot size, the acquired projections not only contain absorption contrast, but also phase contrast due to refraction of the X-rays. Although the resulting edge enhancement can be beneficial in radiography, the tomographic reconstruction of such mixed projections using a conventional algorithm yields cross-sectio...

Fast Splitting-Based Ordered-Subsets X-Ray CT Image Reconstruction

Using non-smooth regularization in X-ray computed tomography (CT) image reconstruction has become more popular these days due to the recent resurgence of the classic augmented Lagrangian (AL) methods in fields such as totalvariation (TV) denoising and compressed sensing (CS). For example, undersampling projection views is one way to reduce radiation dose in CT scans; however, this causes strong...