A CMOS readout amplifier for instrumentation applications

An integrated readout amplifier for instrumentation applications in smart sensor systems is presented. A fully integrated CMOS version of such an amplifier has been developed using switched-capacitor techniques. The amplifier system provides differential input capability, programmable amplification, clock generation, and low-pass filtering on the chip. The output signal is continuous in time and the system can be used without any of the special precautions necessary for sampled-data circuits. Emphasis was put on high PSRR (-63 dB at DC), low noise (10-μV_rms input equivalent wideband noise) and offset, low harmonic distortion, and small amplification error (<0.06% at 4 V_pp). To cover a large field of applications, only slightly different realizations can be used for capacitive sensors as well as for resistive sensor bridges     

An unsupervised texture segmentation algorithm with feature spacereduction and knowledge feedback

This paper presents an unsupervised texture segmentation algorithm based on feature extraction using multichannel Gabor filtering. It is shown that feature contrast, a criterion derived for Gabor filter parameter selection, is well suited for feature coordinate weighting in order to reduce the feature space dimension. The central idea of the proposed segmentation algorithm is to decompose the actual segmented image into disjunct areas called scrap images and use them after lowpass filtering as additional features for repeated k-means clustering and minimum distance classification. This yields a classification of texture regions with an improved degree of homogeneity while preserving precise texture boundaries.     

Performance of integrated dynamic MOS amplifiers

The letter presents measured data of two different types of dynamic amplifier which have been integrated in a standard CMOS metal gate technology. For a supply voltage of ±5 V, gains of 70 dB were obtained with a power dissipation of 58 ?W and 500 ?W at clock frequencies of 10 kHz and 100 kHz, respectively. The dynamic range exceeds 100 dB.     

Improving psychologists' contributions to the policymaking process.

Psychologists might contribute to policymaking as advocates or as technicians, but it is sometimes difficult to keep these roles separate. As they approach the policy arena, psychologists need to look at societal outcomes of policies as well as at organizational processes, at the values of interest groups supporting policies, at their own possible proclivities toward narrow thinking, and at research on the nature of society and the ultimate consumers of policies. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unsupervised texture segmentation of images using tuned matchedGabor filters

Recent studies have confirmed that the multichannel Gabor decomposition represents an excellent tool for image segmentation and boundary detection. Unfortunately, this approach when used for unsupervised image analysis tasks imposes excessive storage requirements due to the nonorthogonality of the basis functions and is computationally highly demanding. In this correspondence, we propose a novel method for efficient image analysis that uses tuned matched Gabor filters. The algorithmic determination of the parameters of the Gabor filters is based on the analysis of spectral feature contrasts obtained from iterative computation of pyramidal Gabor transforms with progressive dyadic decrease of elementary cell sizes. The method requires no a priori knowledge of the analyzed image so that the analysis is unsupervised. Computer simulations applied to different classes of textures illustrate the matching property of the tuned Gabor filters derived using our determination algorithm. Also, their capability to extract significant image information and thus enable an easy and efficient low-level image analysis will be demonstrated.     

The use of contrast agents to enhance crack detection via neutron radiography

Contrast agents have been used in a wide variety of neutron radiographic and radioscopic examinations. Useful contrast agents range from simple hydrogenous materials such as water and oil to exotic compounds such as gadolinium chelates. The properties of the contrast agents also vary widely. Considerations such as the ability to penetrate into cracks, the ability to be removed, the neutron cross-section, or the neutron attenuation mechanism, often steer the investigator to select a particular contrast agent. We have quantified the behavior of the following substances as contrast agents: an aqueous liquid penetrant, a solvent-based liquid penetrant, water, a GdCl₃ aqueous solution, and a solution of gadolinium β-diketonate (2,2,6,6-tetramethyl-3,5-heptanedione) (TMHD) dissolved in acetone and methylene chloride. The experimental tests were carried out using wedge-shaped gaps that simulated cracks, and in actual cracks in Inconel tubing. The experimental results showed that an aqueous solution of GdCl₃ used with a wetting agent provided the best performance, but was difficult to remove completely from the crack.     

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     

Smart CMOS image sensor arrays

In this paper, we present several smart image sensor arrays intended for various applications. We discuss the realization of image sensors in CMOS technology and show some examples of one-dimensional (1-D) and two-dimensional (2-D) smart image arrays     

Development of readout electronics for monolithic integration with diode strip detectors

Parallel in-serial out analog readout electronics integrated with silicon strip detectors will bring a reduction of two orders of magnitude in external electronics. The readout concept and the chosen CMOS technology solve the basic problem of low noise and low power requirements. A hybrid solution is an intermediate step towards the final goal of monolithic integration of detector and electronics.     

CMOS magnetic-field sensor system

A magnetic-field sensor system integrated in CMOS technology with additional processing steps necessary for sensor fabrication is presented. The system contains a magnetoresistive permalloy microbridge acting as a sensor, temperature compensation circuitry, programmable readout electronics, reference voltage bias, and clock generation. It features maximum magnetic flux sensitivity of 70 mV/μT (corresponds to the magnetic-field sensitivity of 88.2 mV/(A/m) at μ_r=1) and its temperature gain is below 260 ppm/°C in the range between -50°C and +100°C