近年來，許多文獻提出對數響應較符合人眼的特性，而影像感測器的動態範圍是為最大未飽和訊號和最小可偵測訊號的比值，在影像感測器中是一個重要的參數。因此具有高動態範圍並且具有對數響應的影像感測器是許多人研究的目標，然而為了完成以上的目標，往往須增加硬體複雜度。
因為DPS在像素內部必需使用記憶體，造成DPS的填充率遠低於APS並且需要額外的成本。與其不斷的提升DPS的畫面品質，不如朝如何增加填充率而改進。
在本篇論文中，我們在對數數位畫素感測器的架構中，提出了有效減少像素內部記憶體的方法，使得像素內部需要的數位元件減少，進而提升填充率，另外本文也對多重取樣因時脈無法對準而造成編碼錯誤提出解決方法。

Recently, many papers proposed the characteristic of the logarithmic output response was suitable to human eye’s sensitivity. Dynamic range is the ratio of the largest non-saturating signal to the smallest detectable signal, which has high dynamic range and logarithmic output response are many people’s objectives. But in order to complete the above objectives, the complex of the hardware often increase.
Because DPS (digital pixel sensor) have to use memory within pixel, DPS’s fill factor is less than APS and need extra cost. We should improve the DPS’s fill factor instead of picture quality.
In this thesis, we proposed a high fill factor architecture of pixel based on the multiple sampling logarithmic digital pixel sensor. Because there are less CMOS devices within pixel, we get higher fill factor. Besides, this paper also put forward the solving method for error-coding because of clock missing.

References

[1] Y.-C. Chuang, S.-F. Chen, S.-Y. Huang and Y.-C. King, “Low-Cost Logarithmic CMOS Image Sensing By Nonlinear Analog-To-Digital Conversion,” IEEE Transactions on Consumer Electronics, vol. 51, no. 4, pp. 1212-1217, Nov. 2005.

[2] S. Kavadias, B. Dierickx, D.Scheffer, A. Alaerts, D. Uwaerts and J. Bogaerts, “A Logarithmic Response CMOS Image Sensor with On-Chip Calibration,” IEEE Journal of Solid-State Circuits, vol. 35, no. 8, pp.1146-1152, 2000.

[3] L.-W. Lai, C.-H. Lai and Y.-C. King, “A Novel Logarithmic Response CMOS Image Sensor with High Output Voltage Swing and In-Pixel Fixed-Pattern Noise Reduction,” IEEE Sensor Journal, vol. 4, no. 1, pp. 122-126, 2004.

[4] Alistair Kitchen and Amine Bermak, “Time Domain Analogue to Digital Conversion in a Digital Pixel Sensor Array,” Proceedings of the Second IEEE international Workshop on Electronic Design, Test and Applications（DELTA’04）28-30 Jan. 2004 Page(s):108 - 112

[5] A. Kitchen, A. Bermark and A. Bouzerdoum, “A Digital Pixel Sensor Array with Programmable Dynamic Range,” IEEE Transactions on Electron Devices, vol. 52, no. 12, pp. 2591-2601, Dec. 2005

[6] Amine Bermak and Yat-Fong Yung, “A DPS array With Programmable Resolution and Reconfigurable Conversion Time,” IEEE TRANSACTIONS ON VERY LARGE SCALE INTERGRATION（VLSI）SYSTEM, VOL. 14, VO. 1, UANUARY 2006 Jan. Page(s):15 – 22, 2006.

[7] A. El Gamal and H. Eltoukhy, “CMOS IMAGE SENSORS,” IEEE Circuits and Devices Magazine, vol. 21, pp. 6-20, 2005.

[8] Seogheon Ham and Yonghee Lee, “COMS Image Sensor with Analog Gamma Correction using Nonlinear Single-Slope ADC,” IEEE ISCAS 2006

[9] D. Yang, A. El Gamal, B. Fowler and H. Tian, “A CMOS Image Sensor with Ultra Wide Dynamic Range Floating Point Pixel Level ADC,” ISSCC Digest of Technical Papers, San Francisco, CA, February 1999

[10] D. Yang, B. Fowler and A. El Gamal, “A Nyquist Rate Pixel Level ADC for CMOS Image Sensors,” IEEE Journal of Solid State Circuit, pp. 348-356, March 1999

[11] S. Kleinfelder, S. H. Lim, X. Q. Liu and A. El. Gamal, “A 10,000 Frames/s CMOS Digital Sensor,” IEEE Journal of Solid Stage Circuits, Vol. 36, No. 12, December 2001

[12] C.-H. Lai, Y.-C. King and S.-Y. Huang, “A 1.2-V 0.25μm Clock Output Pixel Architecture with Wide Dynamic Range and Self-Offset Cancellation,” IEEE Sensors Journal, vol. 6, no. 2, pp. 398-405, Apr. 2006.

[13] A. Bermak, “A CMOS imager with PFM/PWM based analog-to-digital converter,” in Proc. IEEE Int. Symp. Circuits and Systems, vol. 4, May 2002, pp. 53–56.

[14] A. Kitchen, A. Bermak, and A. Bouzerdoum, “A PWM digital pixel sensor based on asynchronous self-resetting scheme,” IEEE Electron Device Lett., vol. 25, no. 7, pp. 471–473, Jul. 2004.

[15] J. Doge, G. Schonfelder, G. T. Streil, and A. Konig, “An HDR CMOS image sensor with spiking pixels, pixel-level ADC, and linear characteristics,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 49, no. 2, pp. 155–158, Feb. 2002.

[16] E. Culurciello, R. Etienne-Cummings, and K. A. Boahen, “A biomorphic digital image sensor,” IEEE J. Solid-State Circuits, vol. 38, no. 2, pp. 281–294, Feb. 2003.

[17] D.H. Woo, C.H. Hwnag, Y.S. Lee and H.C. Lee, “Time-based pixel-level ADC with dynamic range for 2-D LWIR applications,” ELECTRONICS LETTERS 7th JULY 2005 Vol. 41 No. 14

[18] D.Yang, A, El Gamal, “Comparative Analysis of SNR for Image Sensors with Widened Dynamic Range”. Proceeding of SPIE, volume 3649, San Jose. CA, February 1999

[19] S. Bernard, F. Azaïs, Y. Bertrand and M. Renovell, “Analog BIST generator for ADC testing”. IEEE International Symposium on Defect and Fault Tolerance in VLSI systems (DEF’01), 2001.

[20] Amine Bermak, Alistair Kitchen, “A Novel Adaptive Logarithmic Digital Pixel Sensor”. IEEE photonics technology letters, VOL. 18, NO. 20, OCTOBER 15, 2006

[21] Y. Chen, F. Yuan, and G. Khan, “A 2-stage memory write scheme for CMOS pulse-width-modulation digital pixel sensors”. Circuits and Systems, 2008. MWSCAS 2008. 51st Midwest Symposium on Publication Date: 10-13 Aug. 2008