A digital pixel image sensor for real-time readout

An experimental digital image sensor that converts analog video signals into 8-bit digital signals for each unit pixel, and reads out the signals at an operating clock of standard TV has been developed. Each pixel is equipped with a photodiode, a 1-bit analog-to-digital converter (1-bit ADC), an 8-bit pulse counter, and a signal processing circuit. The sensor system displays a two-dimensional (2-D) image in real time. The 1-bit ADC has a dynamic range of 110 dB at an operating voltage of 1.3 V. “Knee” characteristics and the results of an investigation into random noise sources in the circuit are also described     

Arbitrated address-event representation digital image sensor

An 80×60 pixels arbitrated address-event imager has been designed and fabricated in a 0.6 μm CMOS process. The output bandwidth is allocated according to the pixel's demand. The imager has a large dynamic range: 200 dB (pixel) and 120 dB (array). The power consumption is 3.4 mW in uniform indoor light. The imager is capable of 8.3 K effective frames per second     

Three-TFT image sensor for real-time digital X-ray imaging

A new current-programmed, current-output active TFT image sensor suitable for real-time X-ray imaging (e.g. fluoroscopy) using hydrogenated amorphous silicon (a-Si:H) thin-film-transistor (TFT) technology is introduced. The proposed pixel circuit can successfully compensate for characteristic variations such as mobility and threshold voltage shift in a-Si:H TFTs. Simulation and measurement results show that high on-pixel amplification can be accomplished with this pixel circuit.     

用于低噪声CMOS图像传感器的流水线ADC设计及其成像验证

在对低噪声CMOS图像传感器的研究中,除需关注其噪声外,目前数字化也是它的一个重要的研究和设计方向,设计了一种可用于低噪声CMOS图像传感器的12 bit,10 Msps的流水线型ADC,并基于0.5μm标准CMOS工艺进行了流片。最后,通过在PCB测试版上用本文设计的ADC实现了模拟输出的低噪声CMOS图像传感器的模数转换,并基于自主开发的成像测试系统进行了成像验证,结果表明,成像画面清晰,该ADC可作为低噪声CMOS图像传感器的芯片级模数转换器应用。     

A self-scanned solid-state image sensor

An experimental television camera incorporating a completely integrated self-scanned solid-state image sensor has been built. The integrated sensor includes a photosensitive array having 32 400 picture elements, two 180-stage shift register scan generators and associated video coupling transistors. This large-scale integration of more than 100 000 components was carried out in the laboratory entirely by evaporated thin-film techniques. Each element of the photosensitive array comprises one or two photoconductors of CdS or CdS-CASe mixture, each in series with a diode. The 180-stage scan generators utilize 540 CdSe TWF's deposited upon a glass snbstrate. Center-to-center spacing of elements in the array and in the scan generators is 2 mils. The array is scanned at conventional television scan rates permitting the picture to be displayed upon a commercial television receiver. The camera is connected to the receiver either through a cable or through a UHF link with camera and transmitter powered by a self-contained battery. Camera circuits other than the integrated sensor employ conventional transistors and integrated components. Progress toward the development of an improved sensor having more picture elements is outlined.     

A multispectral image sensor array

A silicon monolithic multispectral photosensor device is described. Fabrication techniques and preliminary spectral response data are presented.     

A digital fiber-optic liquid level sensor

A fiber-optic liquid level sensor is presented which directly outputs digitally encoded liquid level information. The sensor operates on selective coupling at the liquid surface between a source waveguide and an array of digitally masked receiving waveguides. The receiving waveguides carry optical "high/low" signals to a remote detector and discriminator circuit. The sensor is capable of liquid level resolution of ± 2 mm over a range of up to several meters. A 40-cm-long prototype sensor has demonstrated an optical signal-to-noise ratio of 10-20 dB for several different transparent and semi-transparent liquids. The digital nature of the sensor provides good isolation from drift and the effect of tilt, source intensity fluctuations, and variations in liquid characteristics. Optical fibers are the only connections to the liquid tank, providing complete electrical isolation. The associated electronics are relatively simple and inexpensive.     

CMOS图像传感器新技术——C^3D

C3D(CMOS Color Captive Device)是新一代半导体成像技术,它不仅提高了像素设计技术,也改进了生产工艺.采用这种技术生产的0.25 μ mCMOS图像传感器能够在不牺牲性能的前提下增加晶体管的数量和占空因数(Fill Factor).除了增加像素设计的选择方案之外,还可实现更为复杂的功能和更低的功耗,并且在速度方面也很有优势.     

A small pixel CMD image sensor

A charge modulation device (CMD) imager with pixel dimensions of 7.3 μm(H)×7.6 μm(V) was designed, fabricated, and examined. These pixel dimensions are suitable for an HDTV imager with a 1-in image format. The optical aperture ratio is 34%. The effective number of pixels in the imager is 660 horizontal and 492 vertical. The saturation signal current is 17 μA/pixel at an exposure of 1 lx-s with good linearity of photoconversion characteristics. The peak of its spectral response occurs at a wavelength of 575 nm. The blooming suppression ratio of the CMD was measured to be -122 dB. The sensor produces a high-quality image with no degradation in spatial resolution and no image lag. These features show that the CMD imager is eminently suitable for a further high-resolution imager sensor     

一种新的数字图像隐藏技术

提出了一种基于DES加密算法思想的图像置乱技术，并采用融合的方法对图像信息进行隐藏。实验结果表明，该方法具有较高的嵌入容量和好的隐藏效果，而且对于图像剪切处理具有一定的鲁棒性。     

一种半脆弱性数字图像水印算法

本文基于JPEG有损压缩提出了一种半脆弱性数字图像水印算法。实验测试表明,所提出的算法不会明显影响图像的主客观质量,对JPEG有损压缩具有一定的顽健性,可以有效地进行篡改检测,达到检测和标示图像内容真实性的目的。     

A novel adaptive logarithmic digital pixel sensor

A major problem associated with complementary metal-oxide-semiconductor and charge couple device imagers is their limited dynamic range (DR), typically 60-70 dB. This falls far short of covering the wide illumination ranges found in natural scenes (typically 120-140 dB). Biological retinas are known to feature adaptive, logarithmic-type responses enabling them to cover a very wide DR, without compromising the resolution. This letter presents a novel way to realize such an adaptive logarithmic response by combining a digital time domain vision sensor and a simple adaptive digital quantizer. This letter presents the theory and experimental results for an adaptive logarithmic response sensor featuring over 100-dB DR.     

A meander channel CCD linear image sensor

A new type of 1024-element linear image sensor has been developed using a CCD with a meander channel (MCCD). Its simple electrode pattern with no contact windows for clocking promises high yield in the production.     

A self-scanned image sensor employing MOS structure

Studies were carried out on a self-scanned image sensor comprising a linear integrated-circuit array of photodiodes and metal-oxide-semiconductor (MOS) transistors. It was found that the maximum scanning rate is about 2.5×10⁵bits/s, and that the value is mainly restricted by the photo-induced current and the junction capacitance of the photodiode.     

A remote pressure sensor with digital signal interface

A high performance pressure sensor circuit is described with a digital signal interface for accurate remote sensing of pressure. The signal conditioning circuitry converts sensor resistance variation into a digital signal. Automatic offset error correction prevents long term and temperature drift effects on overall performance. The digitized signal is detected remotely over two wires by means of optical or ferrite coupling. The same two wires were used for power supply delivery. Floating operation allows good performance in a noisy environment. Test results have shown less than 0-25 psi/°C input equivalent pressure error in a temperature range of – 25°C to +75°C. The non-linearity was less than 0-2% in a dynamic pressure range of 500/1 at room temperature.     

A feature-based robust digital image watermarking scheme

A robust digital image watermarking scheme that combines image feature extraction and image normalization is proposed. The goal is to resist both geometric distortion and signal processing attacks. We adopt a feature extraction method called Mexican hat wavelet scale interaction. The extracted feature points can survive a variety of attacks and be used as reference points for both watermark embedding and detection. The normalized image of an image (object) is nearly invariant with respect to rotations. As a result, the watermark detection task can be much simplified when it is applied to the normalized image. However, because image normalization is sensitive to image local variation, we apply image normalization to nonoverlapped image disks separately. The disks are centered at the extracted feature points. Several copies of a 16-bit watermark sequence are embedded in the original image to improve the robustness of watermarks. Simulation results show that our scheme can survive low-quality JPEG compression, color reduction, sharpening, Gaussian filtering, median filtering, row or column removal, shearing, rotation, local warping, cropping, and linear geometric transformations.     

A digital readout technique for capacitive sensor applications

The difference between two capacitors is measured digitally using a charge redistribution technique incorporating a comparator, MOS switches, a successive approximation register, and a digital-to-analog converter. The technique is insensitive to comparator offset and parasitic capacitance, and the effect of MOS switch charge injection is measured and canceled. Extensive measurements have been made from test chips fabricated in 3-μm CMOS technology. Detection of percent differences of <0.5% on 20-100-fF capacitors has been successfully demonstrated     

Pixel design of pulsed CMOS image sensor for retinal prosthesis with digital photosensitivity control

A newly designed pulse frequency modulation photosensor for use in retinal prosthesis is proposed and demonstrated. The pixel converts the intensity of incident light into biphasic current pulses at frequencies suitable for the electrical stimulation of retinal neurons. Experimental results showed that the device was sensitive over a dynamic range of input light of about 120 dB, and that photosensitivity could be varied from 0 dB to around -40 dB.     

全面了解数字温度传感器规范

为了实现最佳性能并确保系统稳 健性,就必须要进行系统监控测量.其 中一个必需的典型测量项目就是环境温 度.使用简单的数字温度传感器进行该 测量将为系统设计人员提供如下保证: 组件正常工作,系统处于其性能或校准 限值范围内,不会使用户遇到危险.     

A high-dynamic-range CMOS image sensor for automotive applications

In this paper, a 256×256 pixel CMOS imager is described that exhibits 120 dB dynamic range, 56 dB signal-to-noise ratio (SNR), 65% fill factor, and an effective frame rate of 50 Hz. This has been achieved using a unique combination of a multiexposure and a multigain linear readout. The imager has been integrated in 1 μm double-metal CMOS technology. The intended application is for driver's assistant systems, but the imager can be used for a wide range of applications requiring high dynamic range