Nenad Stevanovic

A CMOS image sensor for high-speed imaging

Acquisition of the images of fast-moving objects requires imagers with high photoresponsivity at short integration times, synchronous exposure, and high-speed parallel readout. Previous CMOS implementations yield frame rates around 500 frames/s at integration times ranging from 75 to 200 ps, and some use rolling shutter only. This CMOS imager achieves more than 1000 frames/s with integration time in synchronous exposure variable between 1 /spl mu/s and 150 /spl mu/s. The 256/spl times/256 pixel imager is realized in a single-poly double-metal n-well 1 /spl mu/m CMOS technology.

High speed camera system using a CMOS image sensor

In this paper a new camera system for high speed imaging is presented, which is capable of recording images with a resolution of 256/spl times/256 pixels and frame rates in excess of 1000 frames per second. It uses an image sensor with on-chip electronic shutter and has been fabricated in standard 1 /spl mu/m standard CMOS process. The camera system contains an image memory for sequence recording. The camera delivers a very good image quality without any external algorithm for image enhancement and provides a very fast interface between the image acquisition and image processing unit. The CMOS imagers also have the ability to acquire images in a very short period. This allows an adaptation of the camera to various automotive applications like occupancy detection, airbag control, pre-crash sensing, collision avoidance, surveillance, and crash test observation. Moreover, the system architecture makes a combination of several applications possible using just a single image sensor unit.

A smart airbag solution based on a high speed CMOS camera system

In this communication we present a low cost smart airbag solution based on a high speed active CMOS camera system. The system continuously monitors the seats and quickly determines the occupancy status, and a passengers position and size before the airbag is deployed. The camera uses an image sensor fabricated in a 1 /spl mu/m standard CMOS technology and is capable to acquire more than 1000 frames per second. Disturbing temporal instationarities in the captured images caused by illumination variations resulting from lighting condition changes while capturing the scene, and intrinsic motions of the objects in the scene are suppressed effectively by differencing images captured alternately with and without active structured illumination.

A basic design guide for CMOS folding and interpolating A/D converters-overview and case study

The design techniques for analog-to-digital converters (ADCs) require careful optimization in order to minimize the amount of hardware required and enable economical monolithic integration. A basic architectural design guide dedicated to folding and interpolating ADCs is outlined and described. A case study for a 10-bit ADC is treated under consideration of different folding and interpolating factors. The trade-off between chip area, power dissipation, and ADC performance is characterized according to the diverse design variables.

A high speed camera system based on an image sensor in standard CMOS technology

In this contribution a novel camera system developed for high speed imaging will be presented. The core of the system consists of a CMOS image sensor manufactured in a 1 /spl mu/m standard CMOS process. The special merit of the image sensor is the capability to acquire more than 1000 frames/s using a global electronic shutter in each sensor cell. The image sensor itself is embedded in a sensor board that has been developed for digitizing the sensors single serial analog output signal as well as for supplying the sensor with all control signals necessary for proper operation. Both the control signals and the digital output signal (RS-422) are generated on a FPGA-chip. Moreover, a graphical user interface adapted to the frame grabber card used (Matrox Pulsar) has been developed for the purposes of monitoring, high speed acquisition, and image processing.

A high frame rate image sensor in standard CMOS–technology

An integrated CMOS image sensor suitable for monitoring fast motion e.g. in very fast industrial processes, crash tests, and high speed machine vision has been developed and tested. The test chip contains 128×128 active sensor cells and it is equipped with an electronic shutter, advanced column current-mode readout circuits and column voltage buffers. For design and fabrication a standard 1.0 µm n-well CMOS process has been used. The size of a single pixel cell is 27.6 µm × 27.6 µm with a fill factor of 42% incorporating four NMOS transistors. The total chip area is 30mm2. The sensor cells show a linear response to illumination. The test chip is capable to acquire 1030 frames/s.

Surveillance sensor systems using CMOS imagers

Surveillance sensors are being applied in factory automation systems, traffic control, entrapment protection, automotive safety systems and in other applications where information about the occupancy of a scene is required. In order to detect object motion several methods exploiting distinct physical phenomena, e.g. passive infrared sensors or active microwave sensors, have been realized. When comparing all of the applicable methods, the electro-optical approach performs very well with respect to the spatial resolution of the monitored area. Therefore, electro-optical sensors are able to provide additional information, e.g. to predict the direction of motion, or to localize and identify objects. However, convenient image processing systems using CCD sensors for image acquisition and DSP or /spl mu/P boards for signal processing and classification are not well suited for dedicated, powerful and cost-effective optical sensor solutions. In contrast to this mainstream approach CMOS based imaging technologies offer novel solutions in both the design and applications of electro-optical surveillance sensors. This contribution discusses CMOS imager operating principles and describes certain architectures and applications for passive and active surveillance sensors. The capabilities for realizing on-chip motion detection and range sensing using fast shutter devices are illustrated. We conclude with a discussion of the status of CMOS surveillance sensors and suggest trends for future applications.

A temperature compensated linear output RF amplifier with programmable gain control

This paper presents a linear RF amplifier with a novel temperature compensation technique and programmable gain control fabricated in a 0.13mum CMOS technology. The CMOS amplifier suitable for RF output stages provides robust operation over a wide temperature range from -30degC up to +85degC without using high slope PTAT current biasing. The realized amplifier within the transmit path of a Bluetooth chip performs 6 dBm maximum output power in limiting mode and has a 1 dB compression point of 4 dBm with EVM of 6% rms, which is suitable e.g. for class 1 Bluetooth enhanced and standard data rate. The implemented programmable gain control has coarse 6 dB and fine 1dB gain steps

Low-Cost High Speed CMOS Camera for Automotive Applications

The increased demand for more intelligence in automotive applications requires robust low-cost sensory systems . Thi s paper presents low-cost high- speed camera employing novel CMOS sensors capab le of serv ing in different automotive applications. Our camera offers a platform that can be used to perform different tasks like occupancy detection , precrash sensing , collision avoidance, and parking distance control for the driver assistance . Moreover, high-speed camera can be used in component development e .g. in the analysis of high-speed motion in crashtest.

CMOS Image Sensing for Surveillance Applications and Object Tracking

Surveillance sensors are devices that respond to the presence or absence of certain objects or people in the monitored space. These systems usually contain a motion detector which senses temporal variations in the received signal and a control unit that processes the sensor signal and determines the status of the monitored space. Typical areas of applications are residential, commercial, and automotive security systems where the purpose is to detect intruders, or industrial and automotive safety systems where the task is to prevent injuries or fatalities caused by machines or airbags. Currently, most of the motion detectors use either passive infrared (PIR), microwave, or ultrasound technologies for sensing the motion. Since in all cases the measurement of motion happens in a global manner, the systems only respond to the general presence of moving objects but not to the absence of objects or people resting in the monitored space. Thus, the systems fail if additional features like object localization, object identification or the estimation of the direction of motion are desired. To meet these requirements necessary for enhanced surveillance sensors, a reasonable spatial resolution of the monitored space must be ensured. Obviously, this condition complies at its best with optically-based sensors like CCDs and image processing control units like digital signal processors (DSPs) or microprocessors. However, due to the architecture of convenient image processing systems (consisting of an image sensor, a frame grabber, and a processing unit), this approach is often not well adapted to the task of automated surveillance, where low-cost, small, and robust solutions are demanded.