High Performance CMOS Range Imaging: Device Technology and Systems Considerations (Devices, Circuits, and Systems)

This work is dedicated to CMOS based imaging with the emphasis on the noise modeling, characterization and optimization in order to contribute to the design of high performance imagers in general and range imagers in particular. CMOS is known to be superior to CCD due to its flexibility in terms of integration capabilities, but typically has to be enhanced to compete at parameters as for instance noise, dynamic range or spectral response. Temporal noise is an important topic, since it is one of the most crucial parameters that ultimately limits the performance and cannot be corrected. This work gathers the widespread theory on noise and extends the theory by a non-rigorous but potentially computing efficient algorithm to estimate noise in time sampled systems. 
This work contributed to two generations of LDPD based ToF range image sensors and proposed a new approach to implement the MSI PM ToF principle. This was verified to yield a significantly faster charge transfer, better linearity, dark current and matching performance. A non-linear and time-variant model is provided that takes into account undesired phenomena such as finite charge transfer speed and a parasitic sensitivity to light when the shutters should remain OFF, to allow for investigations of largesignal characteristics, sensitivity and precision. It was demonstrated that the model converges to a standard photodetector model and properly resembles the measurements. Finally the impact of these undesired phenomena on the range measurement performance is demonstrated.

本著作專注於基於CMOS的影像技術，特別是噪聲建模、特性分析和優化，以貢獻於高性能影像設計，尤其是範圍影像設計。CMOS因其整合能力的靈活性而優於CCD，但通常需要改進以在噪聲、動態範圍或光譜響應等參數上競爭。時間噪聲是一個重要的議題，因為它是最終限制性能且無法校正的關鍵參數之一。本著作匯集了關於噪聲的廣泛理論，並通過一種非嚴格但可能計算高效的算法擴展了該理論，用於估計時採樣系統中的噪聲。

本著作貢獻於兩代基於LDPD的ToF範圍影像傳感器，並提出了一種實現MSI PM ToF原理的新方法。經驗證，該方法能夠實現更快的電荷傳輸、更好的線性度、暗電流和匹配性能。提供了一個非線性和時變模型，考慮到不希望的現象，如有限的電荷傳輸速度和在快門應保持關閉時對光的寄生敏感性，以進行大信號特性、靈敏度和精度的研究。證明了該模型收斂到標準光電探測器模型並正確反映了測量結果。最後，演示了這些不希望的現象對範圍測量性能的影響。