Advanced Materials Research Vols. 1006-1007

Abstract: The current method is presented to calibrate the constant of Helmholtz coils. Two measurement methods of magnetic field strength are proposed and compared. In order to improve the accuracy, the influence of geomagnetic field is eliminated by changing direction of the magnetic field of Helmholtz coils. When the magnetic field strength is measured by Guassmeter, the calibration uncertainty is 0.12% (k=2). When the magnetic field strength is measured by Fluxmeter and search coil, the calibration uncertainty is 0.30% (k=2).

Abstract: This paper presents a noncontact technique for displacement measurement based on the variation of the pixels positions of a target object in the images captured by CCD or CMOS sensor. A video from a moving structure is made and then it is analyzed frame by frame and the variation of the pixels position of the target object in the structure is calculated for each frame and related with the position of the object in the image. The proposed approach is evaluated to measuring vibrations of a reduced scale model of two-floor building lab structure, which focuses on the advantage of using a unique camera for measurements of structural vibrations. The results obtained are compared to reference model and have shown good agreement.

Abstract: The 3D shape measurement has been one of research hotspots in the field of Mechanical measurement. But general optical 3D shape measurement techniques can only measure the continuous object through the phase unwrapping. It’s very difficult to unwrap the phase of the discontinuous object. To solve this problem, a novel digital holographic interferometry used for measuring the 3D shape is proposed in this paper. In this method, holographic interferograms are generated by object beam and reference beam at different incident angles. Height information of every point at the object surface is extracted independently without the phase unwrapping, thus it can measure the discontinuous object. The simulation and initial experiment results suggest that the method is completely feasible and low-cost, so it has great potential to apply in the industrial production.

Abstract: Unmanned surface vehicles (USV) have become an intense research area because of their extensive applications. Marine radar is the most important environmental perception sensor for USV. Aiming at the problems of noise jamming, uneven brightness, target lost in marine radar images, and the high-speed USV to the requirement of real-time and reliability, this paper proposes the radar image target detection algorithms which suitable for embedded marine radar target detection system. The smoothing algorithm can adaptive select filter in noise, border and background areas, improves the efficiency and smoothing effect. Based on the iterative threshold, the tolerance coefficient is selected by the histogram, ensures the robust of segmentation algorithm. The location, area and invariant moments features can be extracted from the radar image which after connected-component labeling. The actual radar image processing results demonstrate the effectiveness of the proposed algorithms.

Abstract: Insect infestation is a common problem for stored grain. In this paper, a novel pattern recognition approach combining an olfactory neural network entitled KIII with support vector machine (SVM) is proposed and used in conjunction with an electronic nose to generate recognition models. Using this approach, feature vectors are firstly processed by KIII model which stimulates information processing function of olfactory bulb, and then classified by SVM. Through optimization of SVM model parameters, the data are mapped into high dimension space and the stored wheat samples with different degrees of insect damage are distinguished successfully. The experimental results demonstrate that the proposed method can achieve up to 100% classification rate and significantly outperforms the conventional KIII-Minimum Euclidean Distance Classifier.

Abstract: To test granular grain moisture, an online detection system is studied. This system uses a cylindrical capacitive sensor as the detection device. Through the signal detection and processing circuit, using SCM system to complete the online testing of grain moisture. As we all know, for the AC voltage signal, the influence of capacitors and inductors is coupled. So there are some errors no matter measures capacitance alone or measures inductance alone. But this design takes into account of both factors. The relationship between the ratio of the capacitance and conductance and the moisture content is studied. The results show that a small error and a high reliability are obtained.

Abstract: The typical application of ultrasonic tomography is the determination of process parameters like component flow rates and material fractions in industrial environment. Another promising application is non-invasive health monitoring in medical care. Both acoustic attenuation and acoustic impedance inhomogeneity are the main physical quantities that are used to reconstruct the image. When transmission ultrasonic waves are shadowed by hard tissue because of severe attenuation, the reflection mode can be an effective supplement. This paper provides multi-objects reconstruction images by reflection ultrasonic tomography, demonstrating the multi-objects imaging capability of an immersion circular array system. The circular array consists of 36 ultrasonic transducers with 0.5MHz frequency which are ring arranged and embedded in the container wall to serve as both transmitter and receiver. Each time one transducer is fired and in the meantime other transducers are enabled to receive signals. Ultrasonic transmitting, propagating and receiving of the circular array system are simulated by COMSOL Multiphysics® software, after that a series of image reconstructions of the objects with different numbers are obtained through ellipse algorithm.

Abstract: This paper presents the basic principle of gas leak ultrasonic produce, the use of ultrasonic transducer array collecting leak ultrasonic signal, the signal filtering and power spectrum estimation of signal processing algorithms, intelligent gas leak detection system is developed. The detector is convenient to use, can realize quick check gas leak, application of virtual instrument for leakage signal analysis and processing, implementation of gas leak detection and estimation of leakage.

Abstract: The measurement of muzzle vibration responses during gun firing is one of the most important factors for successful design of gun. The use and result are limited by traditional method for the effect of firing environment, so new measurement method is required, the high-speed imaging technology is one choice. The application of high-speed imaging technology in measurement of muzzle vibration is focused on qualitative analysis, in order to discuss the quantitative analysis in this paper, images of muzzle vibration responses are obtained by using high-speed vidicon. Image pretreatment is done for post processing expediently, the process of pretreatment include de-noising by using wavelet transform method, gray processing by using averaged-value method and contrast improvement by using wavelet transform method. After image pretreatment, orientation and matching is done by using correlative matching method, and then the numerical of muzzle vibration responses during gun firing are obtained. So a novel method is afforded for measuring of muzzle vibration responses during gun firing, and the new method has practical significance in the gun’s design, research and production.

Abstract: In order to research the effect of microgravity on plants traits and nutrients. The simulated microgravity greenhouse device was designed to simulate microgravity and research the growth of plants in a closed space. By the black-box method, functional elements of simulated microgravity greenhouse device were decomposed and redesigned by morphological matrix, And PLC was applied to be core control system for the simulated microgravity greenhouse device. The experiment showed that the simulated microgravity greenhouse device could run smoothly and meet the stability requirement. Besides, the plants experimental results showed that the Threonine and Glutamate content in Needle mushroom and Pocket mushroom under the device is higher than the natural group for 40 days.