CMOS image sensor based X-Ray detector noise characterization and its fixed pattern noise correction method

摘要

An X-Ray detector based on CMOS imaging sensors has recently been developed for dental practice application. The X-Ray detector has an inherited fixed pattern noise, as well as other temporal noise due to the CMOS sensor. In order to offer a quality image for dental diagnostics, the X-Ray image must be processed and corrected prior to displaying for customer use. The X-Ray detector noise has been studied and characterized. Three X-Ray devices are used in the investigation. Both an X-Ray source and a green visual LED light source are used to determine the magnitude of X-Ray photon shot noise. Two sets of images, a single-flood image and a 20-averaged image, are studied to characterize the photon response non-uniformity noise. The investigation shows that the device has different noise sources, with fixed pattern noise and X-Ray photon shot noise being the dominant noise sources of the device. Separating these noises from each other helps to improve image quality by reducing or even eliminating some noise components.