High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

Abstract

In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo-diode current were analyzed in detail. The proposed architecture can extend the DR for about 20N log 2 dB at the high end of Photo-diode current with an N bit Up-Down counter. At the low end, it can compensate for the larger readout noise by employing Extended Counting. The Adaptive Delta-Sigma architecture employing a 4-bit Up-Down counter achieved about 160dB in the DR, with a Peak SNR (PSNR) of 80dB at the high end. Compared to the other HDR architectures, the Adaptive Delta-Sigma based architecture provides the widest DR with the best SNR performance in the extended range. 978-1-4673-0323-1/11/$26.00

Digital pixel readout integrated circuit for high dynamic range infrared imaging

“…A block diagram of the DSM architecture with an analog residue output for extended counting is shown in Figure 1. This same technique is compatible with other types of algorithms, such as pulse-frequency modulation [12], but the DSM holds advantages in pixel size, noise performance and control of signals for megapixel-class arrays. The secondary ADC may be outside the pixel or it may involve reconfiguration of the pixel to perform a different type of conversion on the remaining residue as is done in [13].…”