中国科学院机构知识库网格系统: 检索

The application of adaptive enhancement algorithm based on gray entropy in mammary gland CR image (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012, April 21, 2012 - April 23, 2012, Three Gorges, China
Zhang M.-H.; Zhang Y.-Y.

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Mammary gland is composed entirely of soft tissue with approximate density therefore mammary gland CR medicine radiation image presents a low contrast and slight difference changes may be a manifestation of tumor so it is necessary to enhance mammary gland CR image to improve its visual quality in order to meet the demands of doctor's clinical diagnosis. However the general enhancement algorithms over enhance the contrast and noise due to image details lost aiming at the defects a mammary gland CR medicine image adaptive enhancement arithmetic based on image gray entropy is put forward. The arithmetic adapts dizzy image to magnify selected spatial frequency response in order to enhance the edge details of mammary gland CR images. It can adjust weighted factor K according to image gray characteristics namely pixel gray entropy. Experiments results demonstrate that mammary gland CR image enhanced by the algorithm has abundant details and high signal-to-noise ratio moreover CR image enhanced has good visual effect. So the method is effective and fit for enhancing CR medical radiation image edge details. 2012 IEEE.

The application of digital signal processing (DSP) for the real time solving of artillery fire control exterior trajectory (EI CONFERENCE) 会议论文 OAI收割
2012 IEEE 3rd International Conference on Software Engineering and Service Science, ICSESS 2012, June 22, 2012 - June 24, 2012, Beijing, China
作者: Li D.

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Method of gain firing data by calculate the group of differential equation has the advantages of high repeatability and high accuracy But much of the CPU time is occupied by the task of re-iteration in computational processing. Therefore it is not the real time processing. This paper introduces a method to quickly determine angle of firing by iteration method which realizes Runge-Kutta method for the equations of exterior ballistic according to the model of mass center motion of projectile. Moreover it also provides the flow of real-time integral solution and be proved by the simulation of MATLAB. Its accuracy satisfies the requirements. This work can be as reference for the design of opt-electrical fire control system and the demonstration work. 2012 IEEE.

Study on ultra-light secondary baffle for coaxial two-mirror telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Zhang L.; Zhang L.

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The coaxial two-mirror telescope consists of two mirrors facing each other. Classical two-mirror arrangements are Gregorian and Cassegrain. These systems are usually applied to space telescopes and often have optical baffles to prevent stray light from entering the focal plane. The optical baffles consist of concentric rings suspended between the secondary and the primary mirror. The secondary baffle for a large two-mirror optical system is designed and analyzed in this paper. According to mission of a telescope the structure should have high stiffness and high reliability and light weight. Compared with invar aluminum alloy and titanium alloy carbon fiber composite is currently the best material in terms of weight-to-strength ratio. It also has advantages of high temperature tolerance and low thermal expansion. So carbon fiber composite is chosen as material to meet requirements of the coaxial telescope. In this paper optimization method based on finite element analysis (FEA) is used for design the secondary baffle. Minimum weight of the baffle is chosen as an objective function. Thicknesses of former tube and vanes are chosen as variables. Analysis results show that the designed secondary baffle has maximum diameter of 180mm total length of 120mm and weighs 142g. And its fundamental frequency reaches 651Hz. Therefore the baffle has many advantages such as ultra-light weight high stiffness and dimensional stability etc. The optimization method and the baffle design can be helpful to other coaxial telescopes such as Cassegrain Gregorian and their subdivisions. 2012 IEEE.

Determination of optimum process parameters in gas-assisted injection molding (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electrical Information and Mechatronics, ICEIM2011, December 23, 2011 - December 25, 2011, Jiaozuo, China
Zi K.; Chen L.

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With finite element analysis software Moldflow numerical simulation and studies about FM truck roof handle were conducted on gas-assisted injection molding process. The influences of melt pre-injection shot gas pressure delay time and melt temperature were observed by using multi-factor orthogonal experimental method. According to the analysis of the factors' impact on evaluation index the optimized parameter combination is obtained. Therefore the optimization design of technological parameters is done. The results show that during the gas-assisted injection molding optimum pre-injection shot is 94% gas pressure is 15MPa delay time is 0.5s melt temperature is 240 C. This study provided a more practical approach for the gas-assisted injection molding process optimization.

Efficient rate control technique for CCSDS image encoding (EI CONFERENCE) 会议论文 OAI收割
IEEE 2nd International Conference on Computing, Control and Industrial Engineering, CCIE 2011, August 20, 2011 - August 21, 2011, Wuhan, China
Jin L.

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For the limitation of data transmission bandwidth and real time transmission demand generally image compression is required to implement the precise and flexible rate control algorithm. Rate control is an important issue in the image compression field. This paper considers the problem of rate allocation to each encoded segment for CCSDS image compression. One straightforward method is to allocate an equal amount of rate to each segment based on the average of the total number of compressed bytes. The obvious drawback of this method is that different segment will be reconstructed to different quality so the overall quality of the reconstructed image will not be optimized. For the shortage of the original rate control method as to improve the overall quality of the reconstructed image an improved rate control algorithm is proposed for CCSDS image encoding. The key component of the proposed rate control method is the appropriate rate allocation. Experiments on the test images show that the PSNR can be increased at about 0.3dB on average compared to the original algorithm. Therefore experimental results confirm the effectiveness of the proposed algorithm in terms of objective evaluation and the rate-distortion performance of the reconstructed image is improved. 2011 IEEE.

The effect of backlash nonlinear on resonance frequency of electric actuator transmission system (EI CONFERENCE) 会议论文 OAI收割
3rd IEEE International Conference on Advanced Computer Control, ICACC 2011, January 18, 2011 - January 20, 2011, Harbin, China
Han X.; Ge M.; Bai Y.; Jia H.; Ge W.

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In order to study the effect of backlash nonlinear on resonance frequency of electric actuator transmission system then Finally in the premise of meeting the stability the dynamic equilibrium equation of transmission system with backlash is established it makes dynamic simulation analysis for the transmission system based on virtual prototype technology it establishes balanced equation of dynamics system with backlash the effect of backlash on system natural frequency and resonance frequency and the theoretical values and simulation values are compared. Theoretical analysis and simulation results show that the theoretical analysis is basically consistent with simulation results when it is zero backlash and does some theory research and dynamic analysis of backlash nonlinearity and system natural frequency and resonance frequency. First and the error of theoretical analysis and simulation results is within 10%. Therefore according to describing function to theoretically model the backlash nonlinear it can be concluded that considering the transmission system theoretical analysis of backlash nonlinearity is feasible the relation between describing function and the amount of backlash and input amplitude is analyzed and it is much closer to the actual system with instructive significance. 2011 IEEE.

Design of reimaging F/1.0 long-wavelength infrared optical system (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Zhang X.; Zhang X.; Zhang X.

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A reimaging F/1.0 long-wavelength infrared optical system is proposed. The design has a flexible opto-mechanical layout. The design process is as follows. Firstly the catadioptric reimaging system consists of two reflecting mirrors and a relay lenses. Two reflecting mirrors make up of the first imaging system and are therefore free of chromatic aberrations while low dispersion lenses were used in the reimaging system so the optical system do not need achromatic design for a high image quality. Then to correct high-order aberrations resulting from large relative aperture more parameters need to be used with aspheric or diffractive surfaces due to modern optic technology development. Here aspheric is selected for easily manufacture. Finally the design is completed with the help of ZEMAX software. The effective focal length of the objective is 120mm and the field of view (FOV) is 4. The simulated final design shows adequate image quality and the modulation transfer function (MTF) is close to diffraction limit. The effect of the surrounding environmental temperature is analyzed using the concept of thermal defocusing and the thermal compensation is discussed. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Fabrication of high-efficiency ultraviolet blazed gratings by use of direct Ar2-CHF3 ion-beam etching through a rectangular photoresist mask (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, May 24, 2011 - May 26, 2011, Beijing, China
Tan X.

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In ultraviolet spectroscopy groove irregularity and surface roughness of nanometer magnitude can cause a significant loss of diffraction efficiency. Therefore there is a constant need to improve the diffraction efficiency. A blazed grating can concentrate most of the light intensity into a desired diffraction order it is important to control the groove shape precisely so it is the optimum choice among gratings of different kinds of profile. As the operating wavelength of most UV spectral applications is less than 200 nm especially the blaze angle and the apical angle. We have presented a direct shaping method to fabricate EUV blazed gratings by using an ion-beam mixture of Ar+ and CHF2 +to etch K9 glass with a rectangular photoresist mask. With this method the required blaze angle is small we have succeeded in fabricating well-shaped UV blazed gratings with a 1200 line/mm groove density and 8.54 blaze angles and 1200 line/mm groove density and 11.68 blaze angles and the metrical efficiency is about 81% and 78%. The good performance of the gratings was verified by diffraction efficiency measurements. When one uses the etching model the conditions on the ion-beam grazing incident angle and the CHF3partial pressure should be noted. Besides since the etched groove shape depends on the aspect ratio of the photoresist mask ridge if we wish to fabricate larger gratings with this method we must improve the uniformity of the photoresist mask before ion-beam etching. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

The ship-borne infrared searching and tracking system based on the inertial platform (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Li Y.; Zhang H.; Zhang H.; Li Y.; Li Y.

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As a result of the radar system got interferenced or in the state of half silent it can cause the guided precision drop badly In the modern electronic warfare therefore it can lead to the equipment depended on electronic guidance cannot strike the incoming goals exactly. It will need to rely on optoelectronic devices to make up for its shortcomings but when interference is in the process of radar leading especially the electro-optical equipment is influenced by the roll pitch and yaw rotation it can affect the target appear outside of the field of optoelectronic devices for a long time so the infrared optoelectronic equipment can not exert the superiority and also it cannot get across weapon-control system "reverse bring" missile against incoming goals. So the conventional ship-borne infrared system unable to track the target of incoming quickly the ability of optoelectronic rivalry declines heavily.Here we provide a brand new controlling algorithm for the semi-automatic searching and infrared tracking based on inertial navigation platform. Now it is applying well in our XX infrared optoelectronic searching and tracking system. The algorithm is mainly divided into two steps: The artificial mode turns into auto-searching when the deviation of guide exceeds the current scene under the course of leading for radar.When the threshold value of the image picked-up is satisfied by the contrast of the target in the searching scene the speed computed by using the CA model Least Square Method feeds back to the speed loop. And then combine the infrared information to accomplish the closed-loop control of the infrared optoelectronic system tracking. The algorithm is verified via experiment. Target capturing distance is 22.3 kilometers on the great lead deviation by using the algorithm. But without using the algorithm the capturing distance declines 12 kilometers. The algorithm advances the ability of infrared optoelectronic rivalry and declines the target capturing time by using semi-automatic searching and reliable capturing-tracking when the lead deviation of the radar is great. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Contact-impact analys with clearance hinge in flexible multi-body system (EI CONFERENCE) 会议论文 OAI收割
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
Ge M.; Jia H.; Liu B.

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Hinge in mechanical systems exist small clearance and contact deformation After consideration of flexible components cause the system to the wear and tear impact force reduced at the clearance noise contact time increased vibration contact-impact areas expand and clearance also caused disturbance of the rod angular velocity of the linkage. 2011 IEEE. reliability reduce or even failure[1]. Therefore the hinge clearance and the impact of flexible components in kinetic models should be considered. In this paper a nonlinear spring-damper hinge clearance model is considered to establish mechanical system structure of dynamic equations[46] through a four-bar linkage hinge with multi-clearance rotation of ADAMS dynamic simulation for dynamics simulation study. Simulation results show that hinge clearance and link flexible in Four-link mechanism dynamics have a great impact on performance: connection with the clearance lead to pin holes to produce a series of collisions and a larger initial impact force