Sensor Review

Autonomous guidance of initial welding position with “single camera and double positions” method : Table of Contents

Shanchun Wei, Hongbo Ma, Tao Lin, Shanben Chen — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – Recognition and guidance of initial welding position (IWP) is one of the most important steps of automatic welding process, also a key technology of autonomous welding process. The purpose of this paper is to advance an improved Harris Algorithm and grey scale scanning method (GSCM) to raise the precision of image processing. Design/methodology/approach – Through the configuration of “single camera and double positions,” a new set of image processing algorithms is adopted to extract feature points by using the pattern of rough location and subtle extraction, so as to restructure three-dimensional information to guide robot move to IWP in the practical welding environment. Findings – Experiments showed that mean square errors (MSEs) in X, Y, Z-directions for both flat butt joint and flat flange are 0.4491, 0.8178, 1.4797, and 0.5398, 0.4861, 1.1071?mm, respectively. Research limitations/implications – It has a limitation in providing guidance for only one step, and would be more accurate if fractional steps are adopted. Practical implications – Guidance experiments of IWPs on oxidant tank's simulating parts are carried out, whose success rate is up to 95 percent and MSEs are 0.7407, 0.7971, and 1.3429?mm. It meets the demands of continuous and automatic welding process. Originality/value – Improved Harris Algorithm and GSCM are advanced to raise the precision of image processing which influenced guidance precision most.

Advanced flow sensors used to reduce emissions in new Chinese power plant : Table of Contents

Robert Bogue — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to describe the use and benefits of thermal mass flow sensing on a new Chinese power plant. Design/methodology/approach – The rationale behind the use and application of thermal mass flow sensors on a coal-fired power plant is described and the benefits derived are identified. Findings – Use of thermal mass airflow sensors have allowed improved control of the plant's combustion process, leading to greater efficiency, reduced emissions and lower maintenance requirements. Originality/value – This paper illustrates how close measurement and control of the airflow led to improved operation of a coal-fired power plant.

An effective corner detection method using subpixel edge detector and Gaussian filter : Table of Contents

Yih-Chih Chiou, Yu-Teng Liang — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to develop an effective and reliable corner detection algorithm so as to extract all the desired corners successfully. In addition, the influences of edge detection method as well as smoothing technique on the overall performance of corner detection techniques are investigated. Design/methodology/approach – In this paper, an effective corner detection algorithm based on subpixel edge detector and Gaussian filter is presented. First, a subpixel accuracy edge detector is used rather than a pixel accuracy edge detector to detect edges. Second, B-splines approximation technique is used to eliminate the staircase effect of a digital curve. Third, curvature curve derived from the edges is smoothed by a Gaussian filter. Finally, statistical process control technique is applied to detect vertices. Findings – The results show that spatial-moment outperforms chain code as an edge detector. Furthermore, the Gaussian filter should be used to smooth curvature curve instead of smoothing the profile of an object, because the former provides greater impact on the corner detection results. Originality/value – In addition to object recognition, motion tracking and obstacle avoidance, the proposed method also has many important engineering and manufacturing applications such as dimensional measuring, reverse engineering, and machine vision-based computer numerical control (CNC) machining of polygonal sheet metal parts.

INKtelligent printing® for sensorial applications : Table of Contents

Marcus Maiwald, Christian Werner, Volker Zöllmer, Matthias Busse — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to highlight INKtelligent printed sensor structures using maskless depositition technologies. Design/methodology/approach – This paper begins with a general introduction to INKtelligent printing®. Starting with layout and ink development, the fabrication of printed sensors is described in detail. Findings – Printed strain gauges, thermopiles and gas sensitive films are successfully fabricated with maskless deposition technologies, offering advantages for continuous non-destructive measurement compared to conventional sensors. Originality/value – This paper shows a new approach for customized sensor structures. The application of a resource efficient and flexible printing technique for sensor fabrication is demonstrated.

Comparing ability to complete simple tele-operated rescue or maintenance mobile-robot tasks with and without a sensor system : Table of Contents

David Sanders — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to investigate the effect on completion of mobile-robot tasks depending on how a human tele-operator interacts with a sensor system and a mobile-robot. Design/methodology/approach – Interaction is investigated using two mobile-robot systems, three different ways of interacting with the robots and several different environments of increasing complexity. In each case, the operation is investigated with and without sensor systems to assist an operator to move a robot through narrower and narrower gaps and in completing progressively more complicated driving tasks. Tele-operators used a joystick and either watched the robot while operating it, or sat at a computer and viewed scenes remotely on a screen. Cameras are either mounted on the robot to view the space ahead of the robot or mounted remotely so that they viewed both the environment and robot. Every test is compared with sensor systems engaged and with them disconnected. Findings – A main conclusion is that human tele-operators perform better without the assistance of sensor systems in simple environments and in those cases it may be better to switch-off the sensor systems or reduce their effect. In addition, tele-operators sometimes performed better with a camera mounted on the robot compared with pre-mounted cameras observing the environment (but that depended on tasks being performed). Research limitations/implications – Tele-operators completed tests both with and without sensors. One robot system used an umbilical cable and one used a radio link. Practical implications – The paper quantifies the difference between tele-operation control and sensor-assisted control when a robot passes through narrow passages. This could be an useful information when system designers decide if a system should be tele-operated, automatic or sensor-assisted. The paper suggests that in simple environments then the amount of sensor support should be small but in more complicated environments then more sensor support needs to be provided. Originality/value – The paper investigates the effect of completing mobile-robot tasks depending on whether a human tele-operator uses a sensor system or not and how they interact with the sensor system and the mobile-robot. The paper presents the results from investigations using two mobile-robot systems, three different ways of interacting with the robots and several different environments of increasing complexity. The change in the ability of a human operator to complete progressively more complicated driving tasks with and without a sensor system is presented and the human tele-operators performed better without the assistance of sensor systems in simple environments.

Planar capacitive sensors – designs and applications : Table of Contents

Xiaohui Hu, Wuqiang Yang — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to present the sensing mechanism, design issues, performance evaluation and applications for planar capacitive sensors. In the context of characterisation and imaging of a dielectric material under test (MUT), a systematic study of sensor modelling, features and design issues is needed. In addition, the influencing factors on sensitivity distribution, and the effect of conductivity on sensor performance need to be further studied for planar capacitive sensors. Design/methodology/approach – While analytical methods can provide accurate solutions to sensors of simple geometries, numerical modelling is preferred to obtain sensor response to different design parameters and properties of MUT, and to derive the sensitivity distributions of various electrode designs. Several important parameters have been used to evaluate the response of the sensors in different sensing modes. The designs of different planar capacitive sensor arrays are presented and experimentally evaluated. Findings – The response features and design guidelines for planar capacitive sensors in different sensing modes have been summarised, showing that the sensor in the transmission mode or the single-electrode mode is suitable for material characterisation and imaging, while the sensor in the shunt mode is suitable for proximity/displacement measurement. The sensitivity distribution of the sensor depends largely on the geometry of the electrodes. Conductivity causes positive changes for the sensor in the transmission and single-electrode mode, but negative changes for the sensor in the shunt mode. Experimental results confirm that sensing depths of the sensor arrays and the influence of buried conductor on capacitance measurements are in agreement with simulations. Research limitations/implications – Experimental verification is needed when a sensor is designed. Originality/value – This paper provides a comprehensive study for planar capacitive sensors in terms of sensor design, evaluation and applications.

A generic framework for colour texture segmentation : Table of Contents

Padmapriya Nammalwar, Ovidiu Ghita, Paul F. Whelan — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to propose a generic framework based on the colour and the texture features for colour-textured image segmentation. The framework can be applied to any real-world applications for appropriate interpretation. Design/methodology/approach – The framework derives the contributions of colour and texture in image segmentation. Local binary pattern and an unsupervised k-means clustering are used to cluster pixels in the chrominance plane. An unsupervised segmentation method is adopted. A quantitative estimation of colour and texture performance in segmentation is presented. The proposed method is tested using different mosaic and natural images and other image database used in computer vision. The framework is applied to three different applications namely, Irish script on screen images, skin cancer images and sediment profile imagery to demonstrate the robustness of the framework. Findings – The inclusion of colour and texture as distributions of regions provided a good discrimination of the colour and the texture. The results indicate that the incorporation of colour information enhanced the texture analysis techniques and the methodology proved effective and efficient. Originality/value – The novelty lies in the development of a generic framework using both colour and texture features for image segmentation and the different applications from various fields.

The Chinese sensor industry: poised to become world leader? : Table of Contents

Robert Bogue — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to provide an insight into China's burgeoning sensor industry. Design/methodology/approach – Following an introduction to the Chinese economy and sensor market, this paper considers a number of key sensor applications and technologies and highlights a selection of Chinese sensor manufacturers and their products. It concludes with an overview of the country's sensor research effort. Findings – This shows that China's sensor market is expanding very rapidly and is being served by a fast-growing community of manufacturers who are producing large numbers of sensors for physical and chemical variables. The automotive sector is one of the leading users of sensors and is aiding China's micro-electromechanical system industry. China has a large and active sensor research community. Originality/value – This paper provides an up-to-date review of the Chinese sensor industry, illustrating its very rapid, recent growth and huge future potential.

Dual shows, vision and sensors, team to highlight innovation : Table of Contents

Richard Bloss — Sat Jan 23 08:00:06 GMT 2010

Abstract:
Purpose – The purpose of this paper is to review the biannual Vision Show and the companion annual Sensor Expo in Chicago, with emphasis on innovative vision and sensor products introduced. Design/methodology/approach – This paper includes in-depth interviews with exhibitors of vision and sensor products. Findings – Wireless sensors and companion technologies such as energy harvesting and storage are the cutting edge today. In vision, 3D vision is the hot technology, finding objects in space rather than just looking at a flat picture. Practical implications – System designers now have the freedom to place sensors in locations which might previously have been out of the question do to cabling problems. With wireless, location is no longer a criterion. Energy harvesting and storage right at the device insures continuous operation without the need for battery replacement. Originality/value – The paper shows how 3D vision now makes it possible to operate and inspect in the real world rather than just in a flat plain. Robotic operations such as random location or bin picking are now everyday possibilities.