The Iterative Detection Network Suppression of Defocusing and Thermal Noise in Black and White Pictures Shot By a Camera with CCD/CMOS Sensor

摘要

The paper deals with elimination of defocusing and thermal noise out of black & white pictures captured by a CCD/CMOS camera with imperfectly adjusted lens. For purposes of image recovery we can use the MAP criterion based iterative detection network (IDN) containing a number of mutually concatenated functional blocks so-called soft inversions (SISOs). This cellular structure makes IDN suboptimal but also numerically very simple and practically applicable in contrast to an unviable optimal (single-stage) MAP detector. Firstly we focus closer on SISO entities and consequently on the creation of entire IDN, specifically the so-called distributed IDN marginalizing at the symbol level. In the end, image reconstruction example will be presented (using this type of IDN) along with its performance characteristics (BER curves) for various levels of defocus.