Applied Mechanics and Materials Vol. 577

Abstract: Auto-focus is an important technique for auto reconstruction of digital holograms, and works by focusing criterion function which influences the effect of the autofocus greatly. Aiming at Marine Microorganism holograms, this paper proposes a new focused criterion function established according to characteristics of detail discrete degree in reconstruction image changing with FD. Simulation results illustrate that, the proposed method, compared with several existing methods, has better single peak, higher sensibility and higher signal to noise ratio (SNR). The new method can realize autofocus of reconstruction distance to implement auto reconstruction of holograms.

Abstract: Comparison research for XRD patterns between Modulus Maximum denoising (marked MJ) and thresholding denoising (marked Thr) all based on wavelet analysis, and the Savitzky-Golay filter (marked SG), as well as variation of denoising effect with required parameters of SG method, was investigated for the first time. The results showed that the Thr method exhibited a good smoothing effect for mineral XRD patterns with sharp peaks, and the MJ method was more suitable for plant-based XRD patterns with broad dispersive peaks. Although the SG method with the optimized parameters possessed a higher denoising property for both the two kinds of patterns, the determination of optimized parameters was hard and needed to be specified by users.

Abstract: This paper presents a retargeting approach based on semantic analysis. Our approach has better performance in images that have comlicated backgroud or multi-objects. Our aim is to protect important object in retargeting process. So we brought in object recognition and image importance calculation for retargeting. This approach consists of three parts: object recognition, the importance of image calculation and image retargeting. (i) Firstly we optimized semantic texton forest (STF)^[11] and got much better results of object recognition.(ii) Secondly we presented a method called dynamically adjust importance image calculation. (iii) Thirdly we give a retargeting method based on triangular mesh. According to importance image we cover Delaunay triangular mesh on image and solve optimization mesh transforming based on energy function which subjects to least energy loss and boundary restraint. Compared with previous approaches, our method has better result in some complex scene images.

Abstract: In this paper, a 14-pole HTS filter is successfully designed and developed, which based on the reflected group delay method. The principle, design process, simulation are demonstrated. The filter is fabricated on a MgO substrate with double-sided DyBa₂Cu₃O₇ HTS thin films. The filter’s center frequency is 813.5MHz with a bandwidth of 15MHz, the return loss is better than 20dB.

Abstract: A hash function h_MISR that suitable for passive devices is proposed. Taking parallel LFSR as the basic component h_MISR provides the security through one-wayness brought by the information loss in the process of compression. When implemented, the hardware complexity of h_MISR is much lower than Toeplitz hash.

Abstract: To build motion object detection system based on DSP (Digital Signal Processor), the motion object detection algorithm by existing is transplanted to the DSP development environment based on adopted DSP hardware system.DSP migration process of the moving object detection algorithm is expounded. First of all, Real-time Workshop tool module in Simulink to establish CCS project file which can be identified by TMS320DM642, then testis processor in the loop (PIL) to verify its correctness. Create system model by Simulink instead of the traditional programming to create DSP project files shorten the development cycle and improve the enforceability of the program. Theresults show that the project files generated by the Simulink can meet the requirements in terms of complete moving object detection.

Abstract: This paper presents the results of a quaternion based extend Kalman filter (EKF) and complementary filter for ArduPilotMega (APM) attitude estimation. In addition, a new method to get the measurement noise covariance matrix R is proposed. Experimental results show that the two algorithms can meet the requirements, but the complementary filter can yield better performance than EKF.

Abstract: In the study of speech digital signal processing, the resonance peak is the major characteristics in reflecting track resonant. In order to be more conducive to the future development of speech signal processing techniques, three methods of the formant estimation are introduced in the article, namely, Short-time Fourier Transform method, Cepstrum, LPC estimation method. These methods are compared and analyzed by means of MATLAB programming, and it is concluded that LPC method is the best method, which can estimate the formant peaks more accurate.

Abstract: Curvature estimation of 3-dimension discrete points performs an important role in dealing with scan line point cloud and is difficult to calculate. A discrete curvature estimation method based on local space parabola is proposed. Method in this paper is contrasted with circular arc fitting method and simulation experiment shows that the proposed method is feasible and effective with high precision.

Abstract: In this paper, on the basis of the classical Retinex enhancement algorithm, we propose a MSR (Multi-Scale Retinex) algorithm based on HSI color space for foggy images enhancement. This algorithm can self-adaptively choose the Scale of the filter function, and it can automatically merge the enhancement effect of the multi-scales. The algorithm can highlight the detail characteristics of target while maintaining the background smoothly. In order to improve the brightness and contrast of the image, we use the Weber's law and the characteristics of human visual system to select the scale parameters, which can better realized the foggy images enhancement.