CMOS 图像传感器的发展现状

目的　了解当前 CMOS图像传感器的发展状况 .方法　详细介绍了图像传感器的历史背景、发展现状、像素单元的结构、工作原理以及 CMOS图像传感器芯片的整体结构 ,并比较了 CMOS图像传感器和 CCD图像传感器的优、缺点 .结果　指出了 CMOS图像传感器发展趋势 .结论　 CMOS图像传感器具有美好的发展前途     

CMOS图像传感器的消噪技术

目的　介绍 CMOS图像传感器的消噪技术 .方法　比较了 CMOS图像传感器与CCD图像传感器的优缺点 ,分析了 CMOS图像传感器消噪技术的方法 ,介绍了其研制现状及发展趋势 .结果　目前采用的消噪技术有效地降低了噪声 ,提高了信噪比 .结论　预见了CMOS图像传感器消噪技术的发展趋势 .     

CMOS图像传感器赶超CCD图传感器

比较了CMOS图像传感器与CCD图像传感器的优缺点,分析了CMOS图像传感器的结构,研制现状,应用及市场前景。指出随CMOS图像传感技术的发展,CMOS图像传感器可以代替CCD图像传感器,并预见了其发展趋势。     

CMOS图像芯片的性能与应用

1 枢图 CMOS图像芯片,又称CMOS图像传感器或CMOS摄像机,它是由像元阵列（Pixel Array）和处理电路组成,形成一个完整的摄像系统。其示意图可见图1,该图像芯片（camera on a chip）中的处理电路,有行、列选通逻辑、时序与逻辑,模拟信号处理器（ASP）及模数转换器（ADC）等组成。其中定时和控制电路限制信号读出模式、设定积分时间、控制数据输出率等,模拟/数字转换器可以有像素级、列级和芯片级,即芯片有一个单一高速的A/D转换器,列级使用多个较低速度的A/D转换器,而像素级则使用多个低速A/D转换器,CMOS图像传感器图像信号有几种读出模式:整个阵列逐项扫描、窗口感兴趣读出、跳跃式-每隔一个（或两个或更多个像元）像元读出,即允许图像抽取,以增加读出速率。     

图像传感器单粒子效应脉冲激光实验研究

针对设计研制的512×512 CMOS APS图像传感器,采用聚焦脉冲激光束研究了其空间单粒子效应特性。试验结果表明,CMOS APS器件图像传感器存在单粒子翻转（SEU）和单粒子锁定（SEL）现象。验证了CMOS APS图像传感器抗单粒子锁定设计的有效性。当对图像传感器移位寄存器区进行照射时,同时发生单粒子翻转和单粒子锁定,器件其它区域也有类似现象。分析了器件单粒子效应的敏感性,获得了器件发生单粒子翻转和锁定的脉冲激光能量阈值及器件锁定电流大小。     

基于单片机的数码监控装置

本文主要介绍了基于CMOS图像传感器(OV7620)、单片机AT89C51、闪速存储器和以及U盘控制芯片SL811HS的简易数码监控设备.介绍了CMOS图像传感器、USB接口芯片PDIUSBD12的基本原理和使用方法.整个系统由单片机控制,监控的结果以图像数据的形式存储于闪速存储器中,也可以通过USB接口传送到计算机中,实现了800×600图像的实时传输和显示.     

CMOS图像传感器阵列在μ秒级物理暂态摄像系统中的应用

介绍TCMOSN像传感器阵列在物理暂态摄像系统中的应用方法。通过时序控制火花点阵闪光与传感器阵列曝光保持同步，拍摄到0．5μ火花图像．验证了原理的可行性。CMOS图像传感器阵列为4x4方阵，分时顺序控制，拍摄间隔在0-9999μ内可调，为高速摄像技术提供了新的方法。     

CMOS APS图像传感器的像质分析

使用标准CMOS制作工艺生产的有源像素传感器（APS）引起了广泛关注。为了确定CMOS APS成像系统设计的主要参数选择的正确性,以及能否满足要求或指标,需要对相机系统的像质进行分析。考虑到CMOS APS图像传感器与CCD的不同,在分析时计算了CMOS APS成像系统中的镜头、滤光片和焦平面的调制传递函数（MTF）,系统MTF曲线为各个部分MTF值之积。在系统截止频率范围内,利用MTF曲线所围面积的大小来评价系统的成像质量。在系统制造之前,用调制传递函数作为像质的评价方法,看其是否符合使用要求,是十分有价值的工作。     

金标试纸条的三聚氰胺定量检测仪的研制

为了实现对乳制品中三聚氰胺的快速定量检测,研制了一种基于CMOS图像传感器的便携式金标试纸条定量检测仪.依据纳米金颗粒的吸收峰波长及CMOS器件的光谱响应,选择绿光LED作为系统照明光源,通过CMOS采集试纸条反应区域的光强分布得到检测带吸收特征峰曲线.利用特定算法对图像原始数据进行处理,从而有效降低了由于光电、生化和外界因素对系统检测的影响.建立被检测物浓度与检测带曲线特征值的函数关系用以确定样品中目标被测物的浓度.使用该金标检测仪对滴加有三聚氰胺标准样品的金标试纸条进行检测,在质量浓度为10⁵00ng/mL范围内具有良好的线性响应特性,相关系数R2>0.92.对同一金标试纸条各进行10次重复测量,变异系数小于2.5%,说明仪器具有响应快、高灵敏、便携等特点.     

利用CMOS快速数字成像系统拍摄高速运动的物体

研制的CMOS快速成像系统,是基于CMOS图像传感器阵列的成像系统,其传感器阵列具有较高的空间分辨率和时间分辨率,因此可获取高速运动物体的瞬间物理状态。实验结果表明,采用4×4阵列的CMOS成像系统可拍摄到0.5μs的图像。     

A CMOS Time-of-Flight Range Image Sensor With Gates-on-Field-Oxide Structure

This paper presents a new type of CMOS time-of-flight (TOF) range image sensor using single-layer gates on field oxide structure for photo conversion and charge transfer. This simple structure allows the realization of a dense TOF range imaging array with 1515 mum² pixels in a standard CMOS process. Only an additional process step to create an n-type buried layer which is necessary for high-speed charge transfer is added to the fabrication process. The sensor operates based on time-delay dependent modulation of photocharge induced by back reflected infrared light pulses from an active illumination light source. To reduce the influence of background light, a small duty cycle light pulse is used and charge draining structures are included in the pixel. The TOF sensor chip fabricated measures a range resolution of 2.35 cm at 30 frames per second and an improvement to 0.74 cm at three frames per second with a pulsewidth of 100 ns.     

A Snapshot CMOS Image Sensor With Extended Dynamic Range

In this paper, a proof of concept for a snapshot CMOS image sensor with extended dynamic range is presented. A prototype of 32 times 32 pixels has been fabricated using the 1-poly 4-metal CMOS 0.35 mum process available through MOSIS and was successfully tested. The measurements from the test chip showed that the fabricated imager allows wide dynamic range (WDR) operation in a snapshot readout mode. This DR extension has become possible due to a unique in-pixel architecture allowing automatic adaptation of each pixel in the array to its illumination level. To reduce the pixel power dissipation various low-power design techniques have been utilized in the pixel design. A single pixel occupies 18 * 18(mum)² and dissipates 23 nW with 8 bit DR expansion at room light level, and 29 nW at high illumination level, equivalent to clear sky at video rate. The power dissipation of the whole sensor (including the supporting circuitry) is 450 muW at video rate. Sensor design is described, design considerations are shown and measurements from the test chip are presented.     

数码望远镜技术方案优选决策

为了得到数码望远镜开发的最优技术方案,对其设计进行了系统分析,找出了图像传感器类型、有效像素数、光敏面尺寸和结构形式等4个关键因素,并由此给出了4个备选技术方案。采用层次分析法(AHP)对备选方案进行了优选决策,通过实例计算,确定出当前最优技术方案,即采用组合式结构和CMOS图像传感器,图像传感器的光敏面尺寸为1/2英寸、有效像素数为1300k。制作出样机,其望远镜视角放大率8倍,视场角7.2°,照相镜头焦距50mm。进行了对比实验,实验结果与理论分析相符。     

A fast CMOS optical position sensor with high subpixel resolution

This paper describes a novel architecture for an optical position sensor which has been implemented on a single chip using standard digital CMOS technology. The prototype device consists of 20/spl times/20 active pixels and two row and column parallel processing units with corresponding digital decoding logic. The image contour is extracted by means of distributed peak-detection, implemented at pixel level, followed by a digital extraction of the beam centroid position executed at row and column level. The sensor chip achieves up to 3000 frames/s with a position accuracy of 0.013 pixel and a total power consumption of 15 mW at 5 V.     

Geometric centre tracking of tagged objects using a low power demodulation smart vision sensor

In this study, a modulated light detecting smart CMOS image sensor is presented. The design has the ability to sense asynchronous signals transmitted from electronic markers such as flashing light emitting diodes (LEDs) tagged on moving objects. The geometric centre of the detected region is returned as the output result. With the presented sensor, object localisation and position detection functions are simplified, performed at higher speeds in real time and power requirement is reduced. The sensor in-pixel processing filters out the background image data, detects the modulated marker regions and projects the extracted region on the two axes, while the geometric centre extraction units placed at each axis identify the coordinates assigned to the marker. The design presents less sensitivity to object texture compared with techniques based on edge extraction or binarisation. The sensor has been designed as a 64 x 64 pixel VLSI CMOS chip in the 0.35 μm standard CMOS technology and analysed in the presence of mismatches and noise. Issues such as sensor array scalability, speed and power dissipation are also examined in this study and features of the sensor are reported and compared with some previous designs.     

核爆炸光辐射探测系统分析

从核爆炸光辐射的特点出发,对基于高速CMOS图像采集与处理的核爆炸光辐射探测系统从理论和结构上进行了分析.根据实际需求,采用高速CMOS成像器件作为光电传感器、DSP快速图像处理系统为中心进行系统架构.分析了基于图像处理的核爆炸参数测量原理,并对大气传输造成的光辐射测量误差进行了计算,编写了图像处理的相关算法程序.模拟实验表明,基于图像处理的核爆炸光辐射探测系统能准确探测核爆炸的相关参数如当量、俯仰角和距离,与传统方法相比具有高精度和良好的稳定性和可靠性,具有一定的实用价值.     

Optical efficiency of image sensor pixels

The ability to reproduce a high-quality image depends strongly on the image sensor light sensitivity. This sensitivity depends, in turn, on the materials, the circuitry, and the optical properties of the pixel. We calculate the optical efficiency of a complementary metal oxide semiconductor (CMOS) image sensor pixel by using a geometrical-optics phase-space approach. We compare the theoretical predictions with measurements made by using a CMOS digital pixel sensor, and we find them to be in agreement within 3%. Finally, we show how to use these optical efficiency calculations to trade off image sensor pixel sensitivity and functionality as CMOS process technology scales.     

CMOS pixels for subretinal implantable prothesis

This work reports on the design, fabrication, and characterization of CMOS pixels for subretinal implants, which seems to be an effective way to recover visual capabilities in some types of blindness. Two possible approaches are presented for CMOS pixel implementation: 1) an approach based on a light-controlled oscillator (LICOS) using a ring oscillator with an odd number of inverters and 2) an approach based on distributing a square signal at each pixel that filters out a number of pulses depending of the light intensity wave across the chip (WATCH). Both types of pixels fabricated in 0.35-/spl mu/m CMOS demonstrate good mimic of the electrical behavior of human retina, with low-power consumption (typically 1 mW for a 14/spl times/14 matrix of pixels) and having small dimensions (75/spl times/78.5 /spl mu/m/sup 2/ for LICOS and 70/spl times/50 /spl mu/m/sup 2/ for WATCH), which make them suitable for practical implants. Experimental validation is reported on physiological solutions. Because of its characteristic, the proposed matrix of pixels could be considered as one of the first stand-alone highly integrated solutions for subretinal implant chips.     

一种基于数字图像合成的扩展动态范围方法

数码相机中CCD/CMOS图像传感器的饱和电流和背景噪音使得一次曝光很难超过60-80dB 的动态范围。根据人眼对灰度图像的识别特性,可以采用对相同景物二次不同曝光图像软件合成的算法来获取高动态范围的图像。实验结果显示,当景物画面各部分光照明显差别时,这种方法能有效地获得全部细节信息。     

Estimation of saturated pixel values in digital color imaging

Pixel saturation, in which the incident light at a pixel causes one of the color channels of the camera sensor to respond at its maximum value, can produce undesirable artifacts in digital color images. We present a Bayesian algorithm that estimates what the saturated channel's value would have been in the absence of saturation. The algorithm uses the nonsaturated responses from the other color channels, together with a multivariate normal prior that captures the correlation in response across color channels. The prior may be estimated directly from the image data, since most image pixels are not saturated. Given the prior and the responses of the nonsaturated channels, the algorithm returns the optimal expected mean square estimate for the true response. Extensions of the algorithm to the case in which more than one channel is saturated are also discussed. Both simulations and examples with real images are presented to show that the algorithm is effective.