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Article

A. Al‐Salaymeh, M. Alhusein and F. Durst

Thermal flow sensors with a wide dynamic range are at present not available in spite of the large demand which exists for such sensors in practical fluid flow…

Abstract

Thermal flow sensors with a wide dynamic range are at present not available in spite of the large demand which exists for such sensors in practical fluid flow measurements. In this paper, it is shown that the velocity range of a “time‐of‐flight” thermal flowmeter for slowly changing flows can be increased by using wires (or other heating/sensing elements) with large thermal inertia (time constant) and heating the sending wire with a continuous sinusoidal current, instead of discrete, very short, square‐wave pulses as in the usual pulsed‐wire anemometer. The device described here uses two parallel wires of 12.5μm diameter and its usable speed range is 0.05 to 25m/s. Although the present thermal flowmeter can be applied as a point measurement device, the main applications are in pipe flow, especially at very low flow rates. The high sensitivity at low flow rates makes the device especially suitable for this purpose.

Details

Journal of Quality in Maintenance Engineering, vol. 9 no. 2
Type: Research Article
ISSN: 1355-2511

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Article

Xinlong Wang and Shuai Song

– The purpose of this paper is to improve the tracking performance of the tracking loops under high dynamic and severe jamming conditions.

Abstract

Purpose

The purpose of this paper is to improve the tracking performance of the tracking loops under high dynamic and severe jamming conditions.

Design/methodology/approach

First, as the two dominant measurement error sources of the tracking loops, the thermal noise jitter and the dynamic stress error are thoroughly analyzed. Second, a scheme of adaptive tracking loops, which could adaptively adjust the order and the bandwidth of tracking loops, is proposed. Third, real-time detections of the vehicle dynamics and the carrier-to-noise density ratio, and the adaptive bandwidth of the carrier loop are presented, respectively. Finally, simulations are operated to validate the excellent tracking performance of the adaptive tracking loops.

Findings

Based on the principle of minimizing the measurement errors, the loop order and bandwidth are adaptively adjusted in the proposed scheme. Thus, the anti-jamming capability and dynamic tracking performance of the tracking loops could be effectively enhanced.

Practical implications

This paper provides further study on the method of improving the tracking capability under complexly applied conditions of high dynamics and severe jamming.

Originality/value

The detections of carrier-to-noise density ratio and vehicle dynamics are used to adaptively adjusting the loop order and bandwidth, which could not only improve the measurement accuracy but also ensure the stable operation of tracking loops.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 4
Type: Research Article
ISSN: 0002-2667

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Article

Lounis Chermak, Nabil Aouf and Mark Richardson

In visual-based applications, lighting conditions have a considerable impact on quality of the acquired images. Extremely low or high illuminated environments are a real…

Abstract

Purpose

In visual-based applications, lighting conditions have a considerable impact on quality of the acquired images. Extremely low or high illuminated environments are a real issue for a majority of cameras due to limitations in their dynamic range. Indeed, over or under exposure might result in loss of essential information because of pixel saturation or noise. This can be critical in computer vision applications. High dynamic range (HDR) imaging technology is known to improve image rendering in such conditions. The purpose of this paper is to investigate the level of performance that can be achieved for feature detection and tracking operations in images acquired with a HDR image sensor.

Design/methodology/approach

In this study, four different feature detection techniques are selected and tracking algorithm is based on the pyramidal implementation of Kanade-Lucas-Tomasi (KLT) feature tracker. Tracking algorithm is run over image sequences acquired with a HDR image sensor and with a high resolution 5 Megapixel image sensor to comparatively assess them.

Findings

The authors demonstrate that tracking performance is greatly improved on image sequences acquired with HDR sensor. Number and percentage of finally tracked features are several times higher than what can be achieved with a 5 Megapixel image sensor.

Originality/value

The specific interest of this work focuses on the evaluation of tracking persistence of a set of initial detected features over image sequences taken in different scenes. This includes extreme illumination indoor and outdoor environments subject to direct sunlight exposure, backlighting, as well as dim light and dark scenarios.

Details

Kybernetes, vol. 43 no. 8
Type: Research Article
ISSN: 0368-492X

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Article

Vladimir Brajović and Takeo Kanade

When a sensor device is packaged together with a CPU, it is called a “smart sensor.” The sensors really become smart when the tight integration of sensing and processing…

Abstract

When a sensor device is packaged together with a CPU, it is called a “smart sensor.” The sensors really become smart when the tight integration of sensing and processing results in an adaptive sensing system that can react to environmental conditions and consistently deliver useful measurements to a robotic system even under the harshest of the conditions. We illustrate this point with an example from our recent work on illumination‐adaptive algorithm for dynamic range compression that is well suited for an on‐chip implementation resulting in a truly smart image sensor. Our method decides on the tonal mapping for each pixel based on the signal content in pixel's local neighborhood.

Details

Sensor Review, vol. 24 no. 2
Type: Research Article
ISSN: 0260-2288

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Article

Luigi Barazzetti

– The purpose of this paper is to present a new multi-image registration methodology that is able to align a set of hand-held bracketed shots.

Abstract

Purpose

The purpose of this paper is to present a new multi-image registration methodology that is able to align a set of hand-held bracketed shots.

Design/methodology/approach

The procedure is a two-step algorithm where corresponding multi-image points are automatically extracted from the bracketed image sequence and a least squares adjustment recovers transformation parameters.

Findings

The images can be processed with high dynamic range algorithms to combine multiple low dynamic range pictures into a single mosaic with a superior radiometric quality.

Originality/value

Simulated and real examples are illustrated to prove the effectiveness of the developed affine-based procedure.

Details

International Journal of Pervasive Computing and Communications, vol. 10 no. 2
Type: Research Article
ISSN: 1742-7371

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Article

Harikrishnan Ramiah and Tun Zainal Azni Zulkifli

This paper sets out to design and realize a highly linear, wide dynamic range and high switching efficiency integrated CMOS up‐conversion mixer for two‐step IEEE 802.1a…

Abstract

Purpose

This paper sets out to design and realize a highly linear, wide dynamic range and high switching efficiency integrated CMOS up‐conversion mixer for two‐step IEEE 802.1a WLAN transmitter application in 0.18‐μm deep submicron CMOS technology.

Design/methodology/approach

A folded current draining low‐voltage mixer architecture is explored and an extensive simulation carried out utilizing Cadence Spectre‐RF tool in optimizing the linearity, input third‐order intercept point (IIP3), the dynamic range, 1 dB compression point (P−1dB), power dissipation and reduction of switching quad Cgs, input gate‐source capacitance, in enhancing the switching efficiency of the proposed architecture.

Findings

A highly linear, high input dynamic range, low voltage folded up‐conversion mixer architecture is realized in a significant comparable performance with respect to conventional reported architecture, indicating −8.87 dBm of OIP3 corresponding to 15.27 dBm IIP3 and 4.37 dBm of P−1dB in 0.18‐μm CMOS technology.

Research limitations/implications

The optimized mixer architecture is stringent to an up‐converter application. To be utilized as a down converter at the receiver end, parameters, namely as noise figure and conversion gain, are of additional importance.

Practical implications

The designed folded mixer architecture is in need of integration to a two‐step up‐conversion transmitter architecture which relaxes the injection pulling effect for a given low voltage headroom, with low power dissipation design.

Originality/value

In this work, an integrated folded architecture with on‐chip process, voltage and temperature compensated biasing circuit is explored and enhanced, raising awareness of adapting improved multiplier blocks in achieving optimal performance in WLAN transceiver architecture.

Details

Microelectronics International, vol. 24 no. 3
Type: Research Article
ISSN: 1356-5362

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Article

Graham Dalton

Claims recent advances in laser‐based camera technology and 3D analysis software have made production of 3D CAD models from range images a practical proposition. Laser…

Abstract

Claims recent advances in laser‐based camera technology and 3D analysis software have made production of 3D CAD models from range images a practical proposition. Laser based cameras must meet very strict design criteria if they are to operate at long ranges; these criteria are explored. High‐speed laser cameras produce vast quantities of image data; it is shown that this data can be converted swiftly into a 3‐D CAD model.

Details

Sensor Review, vol. 18 no. 2
Type: Research Article
ISSN: 0260-2288

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Article

Luiz Carlos Paiva Gouveia and Bhaskar Choubey

The purpose of this paper is to offer an introduction to the technological advances of the complementary metal–oxide–semiconductor (CMOS) image sensors along the past…

Abstract

Purpose

The purpose of this paper is to offer an introduction to the technological advances of the complementary metal–oxide–semiconductor (CMOS) image sensors along the past decades. The authors review some of those technological advances and examine potential disruptive growth directions for CMOS image sensors and proposed ways to achieve them.

Design/methodology/approach

Those advances include breakthroughs on image quality such as resolution, capture speed, light sensitivity and color detection and advances on the computational imaging.

Findings

The current trend is to push the innovation efforts even further, as the market requires even higher resolution, higher speed, lower power consumption and, mainly, lower cost sensors. Although CMOS image sensors are currently used in several different applications from consumer to defense to medical diagnosis, product differentiation is becoming both a requirement and a difficult goal for any image sensor manufacturer. The unique properties of CMOS process allow the integration of several signal processing techniques and are driving the impressive advancement of the computational imaging.

Originality/value

The authors offer a very comprehensive review of methods, techniques, designs and fabrication of CMOS image sensors that have impacted or will impact the images sensor applications and markets.

Details

Sensor Review, vol. 36 no. 3
Type: Research Article
ISSN: 0260-2288

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Article

Koichi Maezawa, Tatsuo Ito and Masayuki Mori

This paper aims to propose and demonstrate novel microphone sensors based on the frequency delta-sigma modulation (FDSM) technique, which replaces the conventional…

Abstract

Purpose

This paper aims to propose and demonstrate novel microphone sensors based on the frequency delta-sigma modulation (FDSM) technique, which replaces the conventional delta-sigma modulator in the delta-sigma analog-to digital converters. A key of the FDSM technology is to use a voltage-controlled oscillator (VCO) for converting an input analog signal to a 1-bit pulse-density modulated digital signal. High-performance sensors can be realized if the VCO is replaced by an oscillator whose oscillation frequency depends on an external physical parameter.

Design/methodology/approach

Microphone sensors are proposed based on FDSM that uses a suspended microstrip disk resonator, where the backside ground plane is replaced by a thin metal diaphragm. A resonant tunneling diode (RTD) oscillator is also used, as the performance of these sensors significantly depends on the oscillation frequency. To demonstrate the basic operation of the proposal, prototype devices were fabricated with an InGaAs/AlAs RTD.

Findings

A satisfactory noise shaping property, which is a significant nature of delta-sigma modulation, was demonstrated over three decades for the prototype device. A sound-sensing peak was also clearly observed when applying 1 kHz sound from a speaker.

Practical implications

High-performance ultrasonic microphone sensors can be realized if the sensors are fabricated by using a thin InP substrate with high-frequency oscillator design.

Originality/value

In this study, the authors proposed and experimentally demonstrated novel microphone sensors, which are promising as future ultrasonic sensors that have high dynamic range with wide bandwidth.

Details

Sensor Review, vol. 40 no. 5
Type: Research Article
ISSN: 0260-2288

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Article

Javad Dargahi, Mojtaba Kahrizi, Nakka Purushotham Rao and Saeed Sokhanvar

To measure the force applied to the tissue, the traditional endoscopic graspers might be equipped with a kind of tactile force sensor.

Abstract

Purpose

To measure the force applied to the tissue, the traditional endoscopic graspers might be equipped with a kind of tactile force sensor.

Design/methodology/approach

This paper presents the design, analysis, microfabrication and testing of a piezoelectric and capacitive endoscopic tactile sensor with four teeth. This tactile sensor, which is tooth‐like for safe grasping, comprises a Polyvinylidene Fluoride, PVDF film for high sensitivity and is silicon‐based for micromachinability. Being a hybrid sensor, employing both capacitive and piezoelectric techniques, it is possible to measure both the static and dynamic loads. Another feature, to be considered in its design, is the ability to detect pulse. The proposed sensor can be integrated with the tip of any current commercial endoscopic grasper without changing its original design. It is shown that using an array of sensor units, the position of the applied load can still be determined.

Findings

The static response of the sensor is obtained by applying a static force on the tooth and measuring the change in capacitance between the bottom electrode of the PVDF film and the electrode deposited on the surface of the etched cavity. The dynamic response of the device is determined by applying a sinusoidal force on the tooth of the sensor and measuring the output voltage from the PVDF film. The experimental results are compared with both analytical and finite element results. The sensor exhibits high sensitivity and linearity.

Originality/value

Capaciyive and piezoelectic are used to obtain both dynamic,pulse, and static loads. The sensor micromachined so, it can be used in various endoscopic applications.

Details

Sensor Review, vol. 26 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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