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的降低了噪声，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。     

CCD与CMOS传感器的发展与应用

数码影像技术是当代数字成像技术、计算机网络技术发展的产物 ,创作人员通过数码影像系统对图像进行拍摄、修改、整理和传送 ,可以得到各种形式的、图像清晰的画面和照片。数码相机近几年的市场发展备受瞩目 ,其中数码成像技术最重要的关键部件就是CCD与CMOS传感器。本文从影像感测组件的技术与应用角度 ,初步分析CCD与CMOS传感器技术与应用市场的发展趋势。CCD与CMOS传感器的发展随着数码技术、半导体制造技术以及网络的迅速发展 ,CCD与CMOS图像传感器广泛地应用在影视、通讯和IT领域 ,特别是数码相机市场的迅猛发展 ,大大促进…     

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.     

基于复轮廓波变换的图像消噪

为了克服实轮廓波图像消噪后广泛存在的混叠现象,研究了基于双树复小波级联方向滤波器架构的复轮廓波变换图像消噪的若干性质,证明了对于高斯白噪声图像,该变换具有更好的分割能力和抑制能力,并在此基础上提出了一种基于该变换的图像消噪算法.该算法采用蒙特卡罗方法来确定门限收敛因子,并采用这些因子修正3σ准则,对变换域系数模值采用硬阈值处理.图像消噪实验结果表明:该消噪算法比基于实轮廓波变换的消噪算法,具有更高的峰值信噪比和更好的视觉效果.     

基于小波包的超声图像降噪研究

1引言 消除噪声得到高清晰度图像是医学图像处理的关键.目前,人们已经提出许多滤波算法对图像进行滤波消噪,但其大多数方法,尤其是高斯白噪声的消噪法,从本质上说,都是低通滤波的方法,低通滤波是一把双刃剑,它在消除图像噪声的同时,也会消除图像部分有用的高频信息.因此,各种图像消噪方法,其实就是在消噪和保留有用高频信息之间的权衡.     

CMOS影像传感器的信噪比分析

本文使用像素密度归一化方法,对比分析了市场主流厂家生产的多系列数码相机产品中CMOS影像传感器的控噪水平。结论是：2009年尼康推出的采用瑞萨代工传感器的D3S在噪声控制方面达到了顶峰。之后的4年, CMOS控噪技术的发展似乎遇到了瓶颈,各厂商转而在提升像素密度方面大力进取。     

基于DSP网的嵌入式视觉系统

介绍了基于以太网技术和DSP技术嵌入式视觉系统。系统采用CMOS图像传感器直接获得数字图像，经DSP处理后通过以太网传至PC机或视觉网络。系统中还扩展了带触摸屏的TFT液晶屏，可以自成系统的完成图像的采集处理任务。本文给出了系统的硬件设计方案，以及CMOS图像传感器的控制和图像的采集传输的软件流程，并以圆尺寸检测为例介绍系统的实现效果。     

基于红热图像测温技术的图像二维无网格消噪方法

红外热图像测温过程中存在的大量噪声严重制约了红外热图像的精度和准确性,为了准确提取红外热图像中被测物体的相关参数,提出了一种红外热图像二维无网格消噪方法。将双边滤波、异性消噪、无网格消噪进行结合,建立红外热图像二维无网格消噪模型,利用鲁棒回归算法求解模型中相关参数,实现了红外热图像的无网格消噪,提高了红外热图像测温的精度。最后,通过仿真实验验证了提出方法的可行性,为军事、科研等领域的红外热图像的测温提供了理论基础。     

Transient Response and Fixed Pattern Noise in Logarithmic CMOS Image Sensors

Logarithmic CMOS image sensors are appealing for their high-contrast and high-speed response but they require postprocessing to achieve high-quality images. Previously published work has explained the fixed pattern noise (FPN) in these image sensors using a steady-state analysis. This paper explains how the transient response of the readout circuit may also contribute to FPN. Thus, the performance of these CMOS cameras may be optimized with a proper understanding of the transient response, which is explained here through modeling and simulation with some experimental validation. In particular, the gain variation of a logarithmic camera is shown to be caused primarily by premature digitization. As logarithmic and linear active pixel sensors use similar circuits, some results in this paper, e.g., an analysis of readout capacitance, apply equally to the latter.     

工业非胶片射线照相技术 二．数字射线成像

数字射线成像不同于射线实时成像，存数字射线成像系统巾，由各种各样传感器捕获的射线影像信息以电子数据的形式存储存特定的存储器巾，以便进一步处理或存档。本文阐述数字射线成像的一些基本观念、技术、成像系统，以及采用的相关传感器如：1．涂布在非品硅薄膜晶体管上的荧光体：2．涂布在薄膜晶体管上的非晶硒光电导体；3．涂布在电荷耦合器或互补金属氧化物上的荧光体；4．可进行光激励的存储荧光体；5．涂布在线阵列器上的荧光体：6．扫描电子束法等．     

Temperature Dependence of Fixed Pattern Noise in Logarithmic CMOS Image Sensors

This paper presents a model that is then simplified to explain the temperature dependence of fixed pattern noise (FPN) in logarithmic complementary metal–oxide semiconductor (CMOS) image sensors. The simplified model uses the average dark response of pixels, which depends only on temperature, to help predict the FPN in the light response, which depends on temperature and illuminance. To calibrate a logarithmic camera, one requires images that are taken at different temperatures and illuminances, which need not be measured, of a uniform stimulus. To correct the FPN in an arbitrary image, one uses the simplified model parameters, which are estimated once by the calibration, and the average dark response, which is infrequently determined by closing the aperture. Through simulation (using mismatch data from a real CMOS process) and experiment (using a commercial logarithmic camera), an improvement is shown in the residual error per image, after calibration, when the proposed method is compared with a related method in the literature that does not account for temperature dependence.      

Modeling, calibration, and correction of nonlinear illumination-dependent fixed pattern noise in logarithmic CMOS image sensors

At present, most CMOS image sensors use an array of pixels with a linear response. However, pixels with a logarithmic response are also possible and are capable of imaging high dynamic range scenes without saturating. Unfortunately, logarithmic image sensors suffer from fixed pattern noise (FPN). Work reported in the literature generally assumes the FPN is independent of illumination. This paper develops a nonlinear model y=a+bln(c+x)+/spl epsi/ of a pixel for the digital response y to an illuminance x and shows that the FPN arises from a variation of the offset a, gain b, and bias c from pixel to pixel. Equations are derived to estimate these parameters by calibrating images of uniform stimuli, taken with varying illuminances. Experiments with a Fuga 15d image sensor, demonstrating parameter calibration and FPN correction, show that the nonlinear model outperforms previous models that assume either only offset or offset and gain variation.     

Noise Measurement for Raw-Data of Digital Imaging Sensors by Automatic Segmentation of Nonuniform Targets

In this paper, we present a new method for measuring the temporal noise in the raw-data of digital imaging sensors [e.g., CMOS and charge-coupled device (CCD)]. The method is specially designed to estimate the variance function which describes the signal-dependent noise found in raw-data. It gives the standard-deviation of the noise as a function of the expectation of the pixel raw-data output value. In contrast with established methods (such as the ISO 15739), our method does not require the use of a specific target or a particular calibration. This is possible due to an automatic segmentation embedded in the data analysis. We show experimental results for the raw-data from two different CMOS sensors of commercial cameraphones.     

纳米CMOS低噪声放大器的研究

介绍了纳米CMOS器件及其新技术,同时利用安捷伦公司的ADS软件,基于台积电0．18μm的RFCMOS工艺,设计了中心频率为5．2GHz的纳米CMOS低噪声放大器,达到了较好的性能。     

Development of Low Power Cryogenic Readout Integrated Circuits Using Fully-Depleted-Silicon-on-Insulator CMOS Technology for Far-Infrared Image Sensors

We are developing low power cryogenic readout integrated circuits (ROICs) for large format far-infrared image sensors using fully-depleted-silicon-on-insulator (FD-SOI) CMOS technology. We have evaluated the characteristics of MOS FETs fabricated by the FD-SOI CMOS technology and have found that both p-ch and n-ch FETs show good static performance below the liquid helium temperature, where n-ch FETs fabricated by conventional bulk-CMOS technology usually suffer from anomalous behaviors such as kink and hysteresis. We have also designed and fabricated an operational amplifier (OP-AMP) and have successfully demonstrated that the OP-AMP works at the liquid helium temperature with an open loop gain of 7000 and a power consumption of 1.3 μW. The noise is dominated by mainly 1/f and has a value of at?1?Hz.     

A novel logarithmic response CMOS image sensor with high output voltage swing and in-pixel fixed-pattern noise reduction

A novel logarithmic response CMOS image sensor fabricated by 0.25-/spl mu/m CMOS logic process is proposed. The new cell has an output voltage swing of 1 V in the targeted illumination range, which makes it less susceptible to noises in the readout system. Furthermore, the proposed new cell with in-pixel CDS control drastically reduces the fixed pattern noise in logarithmic mode CMOS APS. Comparing with a conventional pixel, a reduction of 10 times in fixed-pattern noise is demonstrated in the new logarithmic response CMOS image sensor.     

Clusters of Spikes in CMOS Image Sensors Irradiated by Protons and Neutrons

The distribution of pixels with high-value dark current in CMOS image sensors irradiated by protons with the energy of 1000 MeV and neutrons with a continuous spectrum simulating the energy spectrum of atmospheric neutrons is explored. Data on generation of spike clusters in the irradiated sensors and the exposure time influence on the cluster parameters are obtained.