Applied Mechanics and Materials Vols. 644-650

Abstract: As the number of students who attend the arts exams has been growing, each admission institutions need to score the human head portraits of art sketch with the number of ten thousand and even 100 thousand. Thus it is an innovative research on how to conduct image recognition with the help of advanced computer technology. Image Recognition Technology is to give the computer the intelligence of human vision, so that the computer can quickly and accurately recognize the object on the input images. However, in the recognition process such factors as light, rotation and shield increase the difficulty of identifying the human head portrait images. In order to get better recognition performance, this paper studies the feature extraction of human head portrait based on SIFT (Scale Invariant Feature Transform). From the practical application, it can be seen that the approach proposed in this paper is feasible and is of good recognition performance.

Abstract: —Feature extraction is a very important part in speaker recognition system. We proposed and implemented a speaker recognition algorithm based on the VQ and weighted fisher ratio of MFCC. To evaluate performance of this algorithm, we built a small speaker recognition system based on the MATLAB. Compared with the traditional feature selection methods, the characteristic vector obtained via this algorithm has the greatest degree of differentiation in the same dimension. According to the test results, the speaker recognition algorithm we proposed in this paper, can significantly increase the accuracy rate of training and recognition, and reduce the data required by calculation, in the case of keeping a higher recognition rate.

Abstract: With SIMD functional unit as part of a wide range of application acceleration, how to effectively use this architecture to optimize the application to become a hot spot compiler optimization. This paper discusses the SIMD instructions and pipeline optimization methods. After using MMX instructions and pipeline optimization, real-time to achieve a strong guarantee pure software receiver.

Abstract: In this paper, frequency spectrum of infrasound signal collected was analyzed based on MATLAB. The infrasound power level of change with frequency distribution and the infrasound harmonic of each frequency component of the sound pressure amplitude can be made up judgment visually by frequency spectrum analysis and amplitude spectrum analysis, and thus we can obtain different conditions of infrasound properties scientifically and quantitatively.

Abstract: The terminal uses data acquisition module to collect antenna parameters of the base station, data is processed by S3C2440 core module and transmitted to management system by wireless communication module. This introduces hardware and software design solution of the terminal. The intelligent terminal can measure coordinates, altitude, azimuth and tilt of base station.

Abstract: Nowadays, signal attracts more and more concerns from all walks of life as an information carrier in the information age. However, Fourier Transform which separately deals with time and frequency domains may not be fully competent as a signal processer in the digitization of communications system. Wavelet analysis is a strong signal processing method, which can not only fetch the features of the signal, but also achieve the signal denoising, compression, determine trends, and other functions .Image denoising and voice denoising were two empirical analyses in this study, which indicate certain research value of wavelet analysis for the development of signal processing.

Abstract: In order to improve the utilization of transmission bandwidth in voice communication, this paper proposes a discontinuous transmission method for LPC speech codec. Firstly, by using the algorithm of voice activity detection (VAD), the received signal is divided into voice frame and mute frame. Transitional frame is introduced when the voice frame is converted to mute frame. Then voice frames and transitional frames are encoded at a normal rate, but mute frames are encoded into silence description (SID) frame at a lower rate, which is sent by a method of discontinuous transmission mode. The transmission frequency of SID frame is adjusted automatically according to the fluctuation of characteristic parameters of background noise in mute frames. Finally, the method is applied to the simulation in the MELP vocoder, and the results show that this method has better adaptability in the transmission of mute signal and the synthesized background noise presents good comfort and continuity in the auditory perception.

Abstract: A robust real-time method for detection of abandoned objects in complex outdoor environments is presented. The system introduces a dual background segmentation method based on feedback modification. One background updates fast and the other updates slow. The slow background is then modified by the detection result to exclude the static foreground. They contribute to build the static foreground region masks which are used to update a counter. Static foreground regions are then extracted from the counter and further filtered by a light and shadow eliminator. The filtered regions are then classified into abandoned or removed objects by comparing the feature of its surroundings and the interior boundary vicinity of the fast background and slow background. The algorithm is simple and computationally less intensive. Experimental results on public video datasets and real image sequences acquired outdoor show its practicality and robustness to moving vegetation, shaking camera, illumination change and crowed scenes.

Abstract: Analysis on the operation principle of digital radio frequency memory range (DRFM) with range gate pull off/in (RGPO/RGPI), a model of jamming signal is found in this paper. The use of stretch in the process of radar seeker receive signal is considered, so that the actual target echoes and jamming echoes will be moved into different frequencies. Then a low pass filter can be utilized to cancel the jamming signal and the actual target echo can be rebuilt through inverse stretch dealing. The simulation results show that this method can effectively suppress jamming signal.

Abstract: Airborne and space remote sensing system are all the important parts of the earth observation system, also being good supplements to each other. Airborne remote sensing has the advantages of being high resolution, good efficiency and flexibility, which makes itself an effective method to rapidly acquire high resolution remote sensing data. Particularly, the technologies of conducting low altitude remote sensing investigation by unmanned aerial vehicles are rapidly developed with a great progress achieved, so there is no doubt that it will plays an important role in the remote sensing geological investigation.