Current-mediated, current-output active pixels ooer the advantages of compact size and simple ope... more Current-mediated, current-output active pixels ooer the advantages of compact size and simple operation in designing large format CMOS image sensors, with performance limited by spatial xed pattern noise. In this paper, a thorough noise analysis is made of the expected performance of a current-output pixel image sensor. This analysis is compared with experimental results from a 512768 array imager fabricated in a 0:7m process, and the eeectiveness of basic error correction techniques are explored. The goal of this study was to determine the performance limits of this device and to gain insight into the design issues needed to develop a high quality current-output imager.
A Robust Algorithm for Optimal Decoding of First-Order - Sequences
An exact recursive formula is derived to describe the structure of an ideal first-order - output ... more An exact recursive formula is derived to describe the structure of an ideal first-order - output sequence as a function of its input. Specifically, it is shown that every - sequence gen- erated by the constant input can be decomposed into a shorter - subsequence whose input may be used to recover that of the original sequence. This formula is applied to develop an algorithm for decoding an -length sequence. Without knowledge of the modulator's initial state, it exhibits an average improvement, over all initial states, of 4.2 dB in output signal-to-noise ratio (SNR) compared with a near-op- timal linear finite impulse response (FIR) filter. The regularity of the ideal first-order - structure with constant inputs permits the algorithm to be extended to bandlimited and noise-corrupted data. A simple error correction procedure is demonstrated, and it is shown that the recursive algorithm can outperform FIR filters on sequences of length having input SNRs as low as 30 dB.
It is possible, using a first-order sigma-delta modulation scheme, to represent an imager's p... more It is possible, using a first-order sigma-delta modulation scheme, to represent an imager's pixel value as an oversampled bit stream. The goal of the project was to demonstrate the feasibility of computer vision algorithms on such sigma-delta encoded bit streams. The computational modules used were constrained to fit within the footprint of a single pixel. This ensures that fully parallel operation could be achieved using a 3D architecture. 3D silicon technology allows multiple wafers to be stacked together and interconnects to be made between adjacent layers. Bonding wafers together in this manner would allow computational modules to be placed directly beneath its associated pixel. This process increases the potential for high parallelism and low power computation. The activity detection algorithm which was developed incorporates a frequency-locking analog storage mechanism with a lowpass filter/monitor to simulate a multimodal adaptive background activity detector. This system...
2009 IEEE International Conference on 3D System Integration, 2009
3D TSV technology will soon be widely available and consumer products with embedded TSVs will be ... more 3D TSV technology will soon be widely available and consumer products with embedded TSVs will be the norm rather than the exception. The roadmap envisioned by most for 3D development shows CMOS image sensors and TSVs as mainstream items in 2009 with heterogeneous stacked systems and logic-on-memory following in 2010 and 2011. By 2015, we expect to see complex embedded devices combining sensors, CPUs, and memories. This roadmap is, however, conditioned on the appropriate 3D design software being available. We present the fundamental elements required for a true 3D design flow. We discuss the requirements for standards, design for manufacturing and test guidelines, and tools needed to solve today's as well as tomorrow's problem. Alongside the 3D technology roadmap we propose a 3D EDA roadmap that will have to be followed in parallel if progress is to continue at the anticipated pace.
Uploads
Papers by Lisa McIlrath