Applied Mechanics and Materials Vols. 427-429

Abstract: In this paper,an novel method would be suggested to achieve an dense 3D reconstruction of objects using photometric stereo without any prior knowledge of light source. Using the photometric images I which is constructed with its columns equal to number of photometric images captured and rows equal to number of pixels in a photometric image. A per pixel initial surface normal estimate is computed based upon SVD of the image matrix I. A effective regularization technique has been applied on the initial normal estimate within the energy minimization framework which via graph cuts to regularize them and preserve the underlying discontinuities better.Finally, the regularized surface normals are integrated to recover the surface of the object. The algorithm has been tested on synthetic as well as real datasets and very encouraging results have been obtained.

Abstract: Cryptography is the field of information security technology research priorities. This paper proposes a chaos-based magic square image cipher algorithm. Firstly, it used magic square algorithm to transform the original image pre-processing, the process is the basis of the original magic square algorithm to improve the ranks of transform. Finally, using logistic, henon mappings generated by scrambling the array with the image, so that the image gray value and the location changed at the same time, encrypted final image. Through experimental validation, we prove that the algorithm has cipher effectiveness, and can effectively resist common attacks.

Abstract: Since soil stabilizer consists of many operating components, it has lots of noise sources, and the major noise sources are relevant. So, it is appropriate to identify the noise source of the soil stabilizer using the partial coherence analysis. In this paper, a multi-input and single-output noise source identification model is firstly established, and then an algorithm is developed for the calculation of the partial coherence function. Finally, an experiment is carried out with an actual soil stabilizer. In the experiment the main noise sources are accurately identified. This work provides some guidance for further study of vibration and noise reduction of the soil stabilizer.

Abstract: Based on video frame differential optical flow field, a method of crucial area detection for surveillance video images of examination room is proposed in this paper. Firstly, the optical flow field was calculated with the difference between two adjacent frames. Secondly, the scene was divided roughly into several blocks, and the blocks of which centroid speed is higher than given threshold were further divided into fine sub-blocks, and furthermore, the sub-block which has maximum centroid speed in the block was marked as the area of abnormal target. Finally, the sub-blocks with exceptional speed in the same observation time slice were judged to be the correlate areas with abnormal speed (CAAS), and the intersection of adjacent CAAS were determined as the crucial area. Experimental results show that the proposed method can effectively detect the abnormal movement area, and can accurately position the crucial area affecting other targets movement.

Abstract: Auto correlation function of BOC signal has the character of milti-values, so acquistion of BOC signal can not simply transplant the algorithm of GPS signal. For this reason, parallel code phase search algorithm and cross correlation characteristics of BOC signal are analyzed. And then, the validity of parallel code phase search algorithm on BOC signal are simulated. After that, point to the insufficiency of parallel code phase search algorithm on the acquisiton of BOC signal at low SNR(signal to noise ratio), an improved acquisition algorithm is presented and used to analyze BOC signal. The results show that the improved algorithm is applicable to BOC(pn, n) signal where p is an integer, which expands the application aera of parallel code phase search algorithm; and that the improved algorithm can improve SNR of acquisition about 15dB compared with that of parallel code phase search algorithm, that is to say, the improved algorithm can enhance acquisiton sensitivity of receivers obviously, which is very important to the design of acquisiton algorithm in receivers.

Abstract: According to a network control system--NCS with short time-delay and packet loss, an state observer is designed firstly in this paper to obtain a state estimation error equation which is equivalent to an asynchronous dynamical system having event incidence constraint. Secondly, SVM is used to identify interferences of the NCS. Finally, making the identification result as compensation term adding to the state observer can make the residual only represent fault term under ideal condition and increase the robustness of NCS for interference, which can improve the fault diagnosis precision. The simulation results prove that the designed observer can diagnose faults effective and the disturbance compensation based on SVM has attained the expected effect.

Abstract: It is well known that determining whether a finite game has a pure-strategy Nash equilibrium is an NP-hard problem and it is an active research topic to find a Nash equilibrium recently. In this paper, an implementation of Dang's Fixed-Point iterative method is introduced to find a pure-strategy Nash equilibrium of a finite n-person game in normal form. There are two steps to find one pure-strategy Nash equilibrium in this paper. The first step is converting the problem to a mixed 0-1 linear programming formulation based on the properties of pure strategy and multilinear terms in the payoff function. In the next step, the Dangs method is used to solve the formulation generated in the former step. Numerical results show that this method is effective to find a pure-strategy Nash equilibrium of a finite n-person game in normal form.

Abstract: The main purpose of underwater image fusion is to combine multi-images about the same object into a high-quality image with abundant information. A new underwater image fusion scheme based on Biorthogonal wavelet transform was presented, which is suitable to underwater computer vision system of AUV. Firstly, median filter algorithm was involved for improving the quality and contrast of two source underwater blurred images. Secondly, the different-position-focused underwater images were decomposed by Biorthogonal wavelet and the wavelet coefficients were acquired for reconstructing the fusion image. Finally, the fused image was constructed using the low-frequency and high-frequency domain fusion rules. By adopting a series of experiments for the underwater images fusion, an integrated underwater image with visible outline and distinguishable inner details was obtained.

Abstract: Infrared images have the high dynamic range characteristic, generally digitized to 14 bit. While most display devices can only show 8 bit images, so high bit-wide infrared image signal should be compressed to low bit-wide display data without losing the important detail information. A new high-dynamic-range compression and detail enhancement algorithm for infrared images is presented in this paper. In the proposed algorithm, the original infrared image is separated into the low-frequency base component and the high-frequency detail component. Then the base component is compressed with the simple gray level linear mapping, and the detail component is enhanced with the S-curve transformation. Finally, the two components are combined to get the 8 bit enhanced image. The experimental results show that the proposed algorithm can achieve the dynamic range compression while effectively preserve and enhance the local detail information.

Abstract: In order to improve the resolution of single image with Pepper and Salt noise, a framework is proposed. In the low resolution imaging model, the Gaussian blur, down-sampling, as well as Pepper and Salt noise are considered. For the low resolution image, the Pepper and Salt noise is reduced through median filtering method. Super resolution reconstruction is performed on the de-noised low resolution image by iterative back projection algorithm. Experimental results show that the Pepper and Salt noise are removed effectively and the peak signal to noise ratio (PSNR) of the super resolution reconstructed image is improved.