Sensor Review : Table of Contents

Spectral evaluation of vegetation features using multi-satellite sensor system (Terra ASTER, Landsat ETM+ and IRS 1D LISS III) in man-made and natural landscape

P.K. Joshi, B. Gupta, P.S. Roy — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose The selection of wavelength region and number of bands is a research problem for remote sensing experts for utilization of data provided by the sensor system. The present study proposes to make an evaluation for optimum band selection and classification accuracy. Design/methodology/approach The entropy, brightness value overlap index (BVOI), optimum index factor (OIF) and spectral separability analysis, i.e. Euclidean distance (ED), divergence, transformed divergence (TD) and Jefferies-Matusita (JM) distance and accuracy of MLC classification were carried out. For the present study Terra ASTER, Landsat ETM+ and IRS 1D LISS III dataset has been used. The first three methods were for the spectral evaluation of the three satellite data used and for determination of information content, variance and spectral overlap among the classes present in the natural and man-made landscape. The fourth method is for selection of spectral band combinations with highest separability of classes using divergence matrices. These band combinations are selected for the classification and subsequent accuracy assessment. Findings The OIF values are clearly indicating that the performance of ASTER data is the best, having the lowest correlation between the bands; hence the separability of the feature is also highest, while LISS III have shown high correlation between the bands, with the poor separability of the features. Landsat ETM+ data are in between these two sensors, better than LISS III but poorer than ASTER. The BVOI outputs of the three datasets of man-made landscape show that band 3 of ASTER has the least overlap of the classes, followed by band 4 of ETM+. Very high overlap of the classes has been found in LISS III data. It has been found from spectral separability analysis of all the three datasets for the man-made landscape that ASTER data with band combination of spectral bands 123468 contains the highest value of all the measures of spectral separability, i.e. ED (291.72), divergence (2,133.37), TD (2,000.00) and JM distance (1,414.10). Research limitations/implications It can be inferred from the present study that spectral resolution plays a very important role in discrimination of vegetation features. ASTER data which are with the highest number of the bands amongst the satellite data used had shown highest classification accuracy, while LISS III data with lowest number of bands had shown lowest accuracy, and Landsat ETM+ stood in between the two sensors. Practical implications It is important to evaluate the sensor systems and their spectral regions for discrimination of vegetation features. The number of bands present in a particular sensor and the spectral regions used in it are some of the crucial factors which decide the usefulness of the data for different applications, including vegetation-related studies. The selection of spectral wavelength region, i.e. spectral bands and the sensor system, presents the research problem for remote sensing experts to suggest the best spectral regions and satellite sensor for the discrimination of the vegetation features in different landscapes, namely man-made and natural. Originality/value In the present study all the three datasets are extensively examined and tested for their vegetation discrimination capabilities using well-established methodologies. All the parameters applied on the datasets revealed that spectral resolution definitely plays a role in the performance of the data as far as discrimination of features is concerned both in natural and man-made landscape with desirable accuracy.

Solid state acoustic wave sensors for real-time in-line measurement of oil viscosity

Kerem Durdag — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper aims to determine the important role of acoustic wave devices in sensing applications such as automotive applications, industrial applications and commercial applications. Design/methodology/approach The paper provides a comprehensive overview of acoustic wave technology and highlights an example of one commercial implementation of its technology for sensing application: a commercially available real-time, online threaded bolt viscosity sensor. Findings The commercially available viscosity sensor can be readily applied in field operations or installed directly on the equipment for continuous monitoring of viscosity to enable technicians/mechanics to test the oil in minutes. Originality/value The paper introduces a new product for the sensing industry.

New-generation nano-engineered biosensors, enabling nanotechnologies and nanomaterials

Vinod Kumar Khanna — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper aims to discover the novelties in biosensor fabrication brought about by breakthroughs in nanomaterials and process techniques, the resulting enhancement in biosensor functionalities, new applications and future possibilities. Design/methodology/approach The impact of nanotechnology on biosensor advancement has been examined. Different directions of biosensor research in the nano era have been highlighted. These include the efforts made through nanotechnology to improve the performance parameters of the existing biosensors, and for implementation of innovative biosensor concepts. Findings Nanotechnology is a key technology in biosensor development. It has permeated into the biosensor field and brought in its wake far-reaching changes. Practical implications Biosensor science and engineering are central to virtually all aspects of life including medical diagnostics, environmental monitoring and biotechnological process control. Therefore, the progress in biosensors brought about by nanotechnology influences one's everyday life. Originality/value The study helps in understanding the applications of nanotechnology in fabricating a new generation of biosensors with improved characteristics. It provides information of value to those involved in biosensor research.

Printed sensors: enabling new applications

Klaus Schroeter — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper aims to discuss the new applications enabled by printed sensors. Design/methodology/approach The paper discusses how silicon-based sensors are manufactured using the time-consuming, expensive, and complicated fabrication process of traditional semiconductor devices and shows what is needed in order to produce such new devices with the advantages of printed sensors. Findings With new materials, new processing technologies and a new manufacturing process, thin, flexible, lightweight, cost-effective sensors are made possible through the power of printed semiconductors. Originality/value This paper should be of value in terms of understanding the pros of printed semiconductors and the resulting sensors which have a number of unique mechanical, electrical, and optical properties.

In-process gap detection in friction stir welding

Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper aims to investigate methods of implementing in-process fault avoidance in robotic friction stir welding (FSW). Design/methodology/approach Investigations into the possibilities for automatically detecting gap-faults in a friction stir lap weld were conducted. Force signals were collected from a number of lap welds containing differing degrees of gap faults. Statistical analysis was carried out to determine whether these signals could be used to develop an automatic fault detector/classifier. Findings The results demonstrate that the frequency spectra of collected force signals can be mapped to a lower dimension through discovered discriminant functions where the faulty welds and control welds are linearly separable. This implies that a robust and precise classifier is very plausible, given force signals. Research limitations/implications Future research should focus on a complete controller using the information reported in this paper. This should allow for a robotic friction stir welder to detect and avoid faults in real time. This would improve manufacturing safety and yield. Practical implications This paper is applicable to the rapidly expanding robotic FSW industry. A great advantage of heavy machine tool versus robotic FSW is that the robot cannot supply the same amount of rigidity. Future work must strive to overcome this lack of mechanical rigidity with intelligent control, as has been examined in this paper. Originality/value This paper investigates fault detection in robotic FSW. Fault detection and avoidance are essential for the increased robustness of robotic FSW. The paper's results describe very promising directions for such implementation.

Laser sensors maximize gains and minimize losses

Walter Pastorius, Mike Snow — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper aims to use 3D laser sensors to collect high-density data that are required for defect detection and localization at high-production rates in manufacturing facilities. Design/methodology/approach The high-speed sensors use Ethernet communications to transport large amounts of data and resolve any synchronization issues. Findings Modern laser sensor technology provides the ability to detect and quantify defects in high-volume manufacturing, wherever defects are located. Laser line sensors provide high speed, high-density data for full surface inspection. Synchronization and communications issues are simplified by the FireSync platform, making system integration straightforward, and maximizing reliability. Originality/value This paper provides detailed 3D data at high speed and uses multiple (binocular) scanners to overcome problems of occlusion.

Enhanced fluorescence-based bio-detection through selective integration of reflectors in microfluidic lab-on-a-chip

Arvind Chandrasekaran, Muthukumaran Packirisamy — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper proposes to examine a simple and cost-effective method of integrating a reflector surface with a silicon-based microfluidic channel for enhanced biosensing through the method of fluorescence in a microfluidics and nanofluidics-based lab-on-a-chip device. Design/methodology/approach Herein, the reflector is integrated with silicon-based microfluidic channels and fluorescence measurements were carried out using alexafluor 647 particles. Two types of microfluidic channel surfaces were used, with and without reflector integration, for the experiments. Findings The experimental results prove that the proposed technique of partial reflector integration within microfluidic or nanofluidic channel surfaces is highly suitable for fluorescence-based detection of single molecules and low concentration fluorophore-tagged receptors. Originality/value It is believed that this is a novel work of integrating a reflector with a microfluidic channel surface for fluorescence-based biodetection. This method will be very useful for fluorescence-based biosensors in detecting low concentration fluorophores and single molecules.

Nanosensors: a review of recent progress

Robert Bogue — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper seeks to consider recent nanosensor developments and the various routes to market through reference to companies which are commercialising these products. Design/methodology/approach This paper initially discusses nanosensor markets and applications. It then illustrates progress in commercial exploitation by considering a number of nanosensor companies and their products. Findings This paper shows that the commercialisation of nanosensors is still in its infancy but a range of products is now reaching the market. In addition to probes for atomic force and scanning probe microscopy, which presently comprise the bulk of the market, innovative biosensors, gas and chemical sensors are having a growing impact. Many of the supply companies are US-based with strong links to universities and have frequently raised significant venture finance and subsequent funds from government agencies involved with defence, homeland security and healthcare. Several of the world's large, high-technology companies are also pursuing nanosensor developments. Originality/value This paper provides an insight into the present-day state of nanosensor commercialisation and gives examples of nanosensor companies and their products.

Accordion fringe interferometry: a revolutionary new digital shape-scanning technology

Richard Bloss — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper seeks to describe an innovative new technology for digitizing the shapes of 3D objects quickly and accurately, which uses accordion fringe interferometry (AFI). Design/methodology/approach Laser beams cast fringe patterns on objects, a digital camera captures images and software constructs point clouds of data. A software package then analyzes the point cloud to extract information such as dimensions or variations in shape for subsequent operations. Findings The AFI approach has already been applied to a number of applications such as: inspection of jet engine airfoils, repair of composite structures and inspection of very delicate objects. Practical implications Point cloud digital shape scanning will find an ever increasing number of applications which will benefit from this fast, accurate and non-contact three-dimensional digitizing technology. Originality/value Users now have a totally new means for capturing dense, three-dimensional data.

Novel X-ray imaging and segmentation of root structures

David Page, Andreas Koschan, Mongi Abidi, Ron Michaels, Dan McDonald — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper seeks to present a novel X-ray system and associated image segmentation algorithm for imaging the below-ground root structures of plants. Design/methodology/approach A matched filter design for segmenting the important root structures from the background clutter in the X-ray images was presented. Findings The feasibility of root imaging and the applicability of matched filters to this problem domain have been demonstrated. Originality/value This research offers a novel approach over existing methods for in situ monitoring of root structures through the application of matched filters for image segmentation.

Nanosensor developments in some European universities

Christine Connolly — Sun Feb 03 14:15:49 GMT 2008

Abstract:
Purpose This paper sets out to highlight selected projects in nanosensor research, demystify the technology and show potential applications in engineering fields. Design/methodology/approach Nano devices for sensing humidity and oxygen concentration are presented with applications in industrial monitoring. Then two approaches to the development of high-density optical memory are given. Next, a miniature flow cytometry system is described for the identification of marine micro-organisms and bacteria. Finally, photonic crystal structures with the ability to control and manipulate light are addressed. Findings Nano is currently a popular term, with a mass of publications in this area. Many universities have set up specialised centres for nanotechnology research. Crystalline materials with shape-selective nanopores can be designed to detect particular chemicals. Successful nanosensors are sensitive, simple, fast and low-cost. Originality/value This paper helps the general engineer to appreciate some aspects of nanotechnology. References to recent publications allow engineers to follow up their interests.