The detection of buried landmines is an important problem in
regions where an army conflict has occurred. In particular, antipersonnel plastic mines cannot be detected with classical techniques, such as metal detectors. So a very promising detection technique based on a thermal model of the soil is applied to detect this kind of mines, in which infrared (IR) images of the soil are used. The core of this technique is the solution of the heat transfer process in the soil and at the soil-air interface, which is a very time consuming process. To overcome this problem we propose an analog circuit which can solve the equations that model the system reducing time cost by taking advantage of the inherent massive parallelism of the circuit. The description of the equations is made with VHDL--AMS and then an automatic synthesis tool generates a circuit which solves the equations.
This paper presents a computer vision system for measuring the weight of gobs during a glass forming process, and a control strategy to correct automatically any weight deviation from a given set-point.
During the formation of molten glass gobs, several noise sources can cause a deviation in the weight from a predefined reference value. Among them, there is a random white-noise disturbance caused by the lack of synchronisation of mechanical devices, the periodic disturbances due to changes in the spinning direction of the tube inside the feeder, and some long-term drifts caused by variations in temperature and viscosity of the raw glass material. The gob weight measurement system developed is based on a monochrome CCD high-resolution camera and photo-detector for synchronizing the frame acquisition. The molten glass provides the illumination, so a high contrast image is obtained with a bright object and dark background. Several image-processing algorithms are presented for reliable area estimation. Assuming that the gob is a symmetric geometry of revolution and uniform mass density, the proposed system estimates the weight of gobs with an accuracy better than ±0.75%. A learning weight control strategy is proposed based on a PI-repetitive control scheme. The weight deviation from a set point is used as a control signal to adjust the glass flow into the feeder. This regulation scheme allows effective weight control, canceling mid and long-term effects. The tracking error, ±1.5%, means a reduction of 40% when compared with a traditional PI controller.
A new image sensor, using CMOS technology, has been designed and fabricated. The pixel distribution of this sensor follows a log-polar mapping, thus the pixel concentration is maximum at the center reducing the number of pixels towards the periphery, having a resolution of 56 rings with 128 pixels per ring. The design of this kind of sensors has special issues regarding the space-variant nature of the pixel distribution. The main topic is the different pixel size that requires scaling mechanisms to achieve the same output independently of the pixel size. This paper presents some study results on the scaling mechanisms of this kind of sensors. A mechanism for current scaling is presented. This mechanism has been studied along with the logarithmic response of these special kind of sensing cells. The chip has been fabricated using standard 0.7 micrometer CMOS technology.
We report on the design, design issues, fabrication and performance of a log-polar CMOS image sensor. The sensor is developed for the use in a videophone system for deaf and hearing impaired people, who are not capable of communicating through a 'normal' telephone. The system allows 15 detailed images per second to be transmitted over existing telephone lines. This framerate is sufficient for conversations by means of sign language or lip reading. The pixel array of the sensor consists of 76 concentric circles with (up to) 128 pixels per circle, in total 8013 pixels. The interior pixels have a pitch of 14 micrometers, up to 250 micrometers at the border. The 8013-pixels image is mapped (log-polar transformation) in a X-Y addressable 76 by 128 array.
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