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Proceedings ArticleDOI

A linear response 200-dB dynamic range CMOS image sensor with multiple voltage and current readout operations

14 Feb 2008-electronic imaging (International Society for Optics and Photonics)-Vol. 6816, pp 681605
TL;DR: Operation methods for high frame rate, linear response, wide dynamicrange (DR), wide dynamic range (DR) and high SNR in a CMOS image sensor are discussed.
Abstract: Operation methods for high frame rate, linear response, wide dynamic range (DR) and high SNR in a CMOS image sensor are discussed. The high frame rate operation is realized by the optimum design of the floating diffusion capacitor, the lateral overflow integration capacitor, the column integration capacitor and the integration periods of multiple voltage and current readout operations. The color CMOS image sensor which consists of the 1/3-inch, 800H × 600V pixels and 5.6-μm pixel pitch with a buried pinned-photodiode, a transfer switch, a reset switch, a lateral overflow switch, a lateral overflow integration capacitor, a photocurrent readout switch, a source follower transistor and a pixel select switch in each pixel has been fabricated by 0.18-μm 2P3M CMOS technology. The image sensor operates the total frame rate of 13-fps with three-time voltage readout operations and one current readout operation and have realized full linear photoelectric conversion responses, over 20-dB SNR for the image of the 18-% gray card at all integration operation switching points and the over 200-dB DR.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Citations
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Journal ArticleDOI
TL;DR: A 1/3-inch, 800H x 600v pixels, 5.6 mum2 color CMOS image sensor with three photocurrent integrations in pixel photodiodes, pixel lateral overflow capacitors and column capacitors fabricated in a 0.18 mum 2P3M CMOS technology has been reported.
Abstract: A 1/3-inch, 800H x 600v pixels, 5.6 x 5.6 mum2 color CMOS image sensor with three photocurrent integrations in pixel photodiodes, pixel lateral overflow capacitors and column capacitors fabricated in a 0.18 mum 2P3M CMOS technology has been reported. The image sensor operates using photodiode integrations and lateral overflow integrations in low light condition and achieves a wide dynamic range (DR) performance of around 100 dB in its one exposure. The wide DR performance in one exposure makes high S/N ratios at the signal switching points in the multiple exposures. The CMOS image sensor also operates using the column capacitor integration in very bright light condition. In the column capacitor integration, the photocurrents generated at the photodiodes are directly integrated at the column capacitors in each column line. The combination of two exposures using the photodiode integrations and the lateral overflow integrations and one exposure using the column capacitors leads to the whole linear photo-electric conversion responses from low light to very bright light region. The fabricated image sensor achieves a high S/N ratio, a fully linear response and over 180 dB DR in the incident light ranging from about 1.4 x 10-2 lx to about 2.4 x 107 lx.

24 citations

Journal ArticleDOI
TL;DR: In this paper, a high-speed measuring optical path for a temperature field using a single camera is designed based on dual-wavelength thermometry, and an on-line temperature measurement system is developed, and its validation experiment indicates a measuring error of less than 1%.

13 citations

Proceedings ArticleDOI
01 Dec 2015
TL;DR: A self-adjusting pixel to combine linear and logarithmic response maintaining high fill factor is proposed for dynamic range imager and simulated in Cadence Virtuoso in 180nm technology node and analyzed for comparative study of dynamic range.
Abstract: Due to low cost, low power consumption and better on-chip functionality CMOS Image Sensor has become the main image sensor for consumer electronics, machine vision as well as in research applications. Besides the advantages, a CMOS image sensor suffers from noises, less sensitivity as well as lacks of Dynamic Range (DR). Logarithmic response Active Pixel Sensor (APS) is a solution for wide dynamic range imager maintaining high fill factor. 3T Linear APS (Active Pixel Sensor) has better performance in low illumination, but very poor sensitivity in low illumination. For 3T logarithmic APS has satisfactory performance in high illumination, but limited sensitivity in low illumination. Few reported to implement both linear and logarithmic capture for a single frame which increases the capture time. Implementation of in-pixel circuitry to combine both linear and logarithmic in a single capture which decreases the fill factor of the pixel is also reported. In this paper, we propose a self-adjusting pixel to combine linear and logarithmic response maintaining high fill factor. The proposed pixel was simulated in Cadence Virtuoso in 180nm technology node and analyzed for comparative study of dynamic range.

12 citations

Proceedings ArticleDOI
TL;DR: A no-reference method based on ISO 20462-2:2005 triplet comparison was created for evaluating tone mapping operators and the results indicate that the method successfully ranked the method in terms of naturalness and pleasantness.
Abstract: High dynamic range (HDR) imaging seems to have developed to a level of soon being a standard feature in consumer cameras. This study was motivated by the need for evaluating tone mapping operators especially for consumer imaging applications. A no-reference method based on ISO 20462-2:2005 triplet comparison was created for evaluating tone mapping operators. Multiple HDR test images were photographed and the method was validated by evaluating 25 tone mapping operators with five test images. Tone mapping operators were evaluated based on image naturalness and pleasantness. The results indicate that the method successfully ranked the method in terms of naturalness and pleasantness. The test image set could be improved for example based on an imaging photo space for HDR photography. The test images of this study are available for non-commercial research purposes.

11 citations

Proceedings ArticleDOI
01 Sep 2007
TL;DR: A 1/3-inch, 800H x 600v pixels, 5.6 mum2 color CMOS image sensor with three photocurrent integrations in pixel photodiodes, pixel lateral overflow capacitors and column capacitors fabricated in a 0.18 mum 2P3M CMOS technology has been reported.
Abstract: A 1/3-inch, 800H times 600v pixels, 5.6 times 5.6 mum2 color CMOS image sensor with three photocurrent integrations in pixel photodiodes, pixel lateral overflow capacitors and column capacitors fabricated in a 0.18 mum 2P3M CMOS process has been reported. It achieves high S/N ratio and fully linear response and over 180 dB dynamic range performances in the incident light range from about 1.4times10-2 Ix to about 2.4times107 Ix.

10 citations

References
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Journal ArticleDOI
TL;DR: In this article, a high-dynamic-range CMOS image sensor consisting of nonintegrating, continuously working photoreceptors with logarithmic response is presented, where the nonuniformity problem caused by the device-to-device variations is greatly reduced by an implemented analog self-calibration.
Abstract: A high-dynamic-range CMOS image sensor consisting of nonintegrating, continuously working photoreceptors with logarithmic response is presented. The nonuniformity problem caused by the device-to-device variations is greatly reduced by an implemented analog self-calibration. After performing this calibration, the remaining fixed pattern noise amounts to 3.8% (RMS) of an intensity decade at a uniform illumination of 1 W/m/sup 2/. The sensor provides a resolution of 384/spl times/288 pixels and a dynamic range of 6 decades in the intensity region from 3 mW/m/sup 2/ to 3 kW/m/sup 2/. It contains all components required for operating as a camera-on-a-chip. The image data can be read out either via a single analog line (video standard) or via a digital interface after undergoing an analog-to-digital conversion on the chip. Additional features like automatic exposure control, averaging of adjacent pixels, and digital zoom have been implemented, making the sensor suitable for a wide field of applications.

159 citations

Proceedings ArticleDOI
29 Aug 2005
TL;DR: In this article, a wide DR CMOS image sensor incorporating a lateral overflow capacitor in each pixel to integrate the overflow charges from the photodiode when it saturates is presented.
Abstract: The wide DR CMOS image sensor incorporates a lateral overflow capacitor in each pixel to integrate the overflow charges from the photodiode when it saturates. The 7.5/spl times/7.5 /spl mu/m/sup 2/ pixel, 1/3" VGA sensor fabricated in a 0.35 /spl mu/m 3M2P CMOS process achieves a 100 dB dynamic range with no image lag, 0.15 mV/sub rms/ random noise and 0.15 mV fixed pattern noise.

125 citations

Journal ArticleDOI
TL;DR: In a CMOS image sensor featuring a lateral overflow integration capacitor in a pixel, which integrates the overflowed charges from a fully depleted photodiode during the same exposure, the sensitivity in nonsaturated signal and the linearity in saturated overflow signal have been improved by introducing a new pixel circuit and its operation.
Abstract: In a CMOS image sensor featuring a lateral overflow integration capacitor in a pixel, which integrates the overflowed charges from a fully depleted photodiode during the same exposure, the sensitivity in nonsaturated signal and the linearity in saturated overflow signal have been improved by introducing a new pixel circuit and its operation. The floating diffusion capacitance of the CMOS image sensor is as small as that of a four transistors type CMOS image sensor because the lateral overflow integration capacitor is located next to the reset switch. A 1/3-inch VGA format (640/sup H//spl times/480/sup V/ pixels), 7.5/spl times/7.5 /spl mu/m/sup 2/ pixel color CMOS image sensor fabricated through 0.35-/spl mu/m two-poly three-metal CMOS process results in a 100 dB dynamic range characteristic, with improved sensitivity and linearity.

113 citations

Proceedings ArticleDOI
K. Hara1, H. Kubo1, Motoki Kimura1, F. Murao1, S. Komori1 
29 Aug 2005
TL;DR: In this paper, a combined linear and logarithmic image sensor is implemented in a 0.35 /spl mu/m 1P3M technology, which achieves 120 dB DR and the offset calibration reduces the FPN from 13 mV to 5 mV.
Abstract: A combined linear and logarithmic image sensor is implemented in a 0.35 /spl mu/m 1P3M technology. The pixel is 7.5/spl times/7.5 /spl mu/m/sup 2/ with a 37% fill factor and contains only 4 transistors. Offset calibration in the logarithmic region is realized by using electrical charge injection into the photodiode. The sensor achieves 120 dB DR and the offset calibration reduces the FPN from 13 mV to 5 mV.

54 citations

Proceedings ArticleDOI
18 Sep 2006
TL;DR: A 2.6times2.6mm image sensor fabricated in 0.35mum 2P3M CMOS contains 64times64 pixels with 20times20mum pixel size and has an extended dynamic range of over 200dB.
Abstract: A 2.6times2.6mm2 image sensor fabricated in 0.35mum 2P3M CMOS contains 64times64 pixels with 20times20mum2 pixel size and has an extended dynamic range of over 200dB. This DR is equivalent to the incident light ranging from about 10-2 to 108 lx with the lens iris fixed

44 citations