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浏览/检索结果: 共9条，第1-9条 帮助 限定条件 专题：长春光学精密机械与物理研究所    第一署名单位    第一作者单位    通讯作者单位     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 The research of digltal CR medicine image adapitive enhancement method (EI CONFERENCE) 会议论文 4th International Conference on Mechanical and Electrical Technology, ICMET 2012, July 24, 2012 - July 26, 2012, Kuala Lumpur, Malaysia Ming-Hui Z.; Yao-Yu Z. 收藏  |  浏览/下载：52/0  |  提交时间：2013/03/25 Digital CR medicine radiation image is in doctor's favor and has became medicine imaging technology new hot spot because of its high gray contrast  powerful computer disposal function  little radiation dosage  non-film diagnosis  different area consultation. But degradation of digital X-ray medical image such as low contrast and blurring during radiographic imaging  caused by complexity of body tissue and effects of X-ray scattering and electrical noise etc.  can worsen the results of analysis and diagnosis. So it is usually needed that CR medicine image is enhanced to improve its vision quality  and easy to doctor's more accurate diagnosis. The general enhancement algorithms over enhancing the contrast and lose image details  aiming at the defects  an enhancement algorithm for CR image is proposed based on the ratio of deviation to mean of domain. The arithmetic enhance CR image edge details by adjusting factor K based on the ratio of deviation to mean of domain of CR image. Experiment results demonstrate that the algorithm enhances CR image detail and CR image enhanced has good visual effect  the adaptive enhancement method is fit for CR medicine image. (2012) Trans Tech Publications  Switzerland.   Research on infrared dim-point target detection and tracking under sea-sky-line complex background (EI CONFERENCE) 会议论文 International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China Dong Y.-X.; Li Y.; Zhang H.-B. 收藏  |  浏览/下载：96/0  |  提交时间：2013/03/25 Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system  the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties.There are some traditional point target detection algorithms  such as adaptive background prediction detecting method. When background has dispersion-decreasing structure  the traditional target detection algorithms would be more useful. But when the background has large gray gradient  such as sea-sky-line  sea waves etc.The bigger false-alarm rate will be taken in these local area.It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature  in our opinion  from the perspective of mathematics  the detection of dim-point targets in image is about singular function analysis.And from the perspective image processing analysis  the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection  its essence is a separation of target and background of different singularity characteristics.The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore  the purpose of the image preprocessing is to reduce the effects from noise  also to raise the SNR of image  and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics  the median filter is used to eliminate noise  improve signal-to-noise ratio  then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line  so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).   Study on the calculation and application for asphericity of rectangle off-axis aspherics (EI CONFERENCE) 会议论文 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China Li J.-F.; Xuan B.; Wang P.; Chen X.-P.; Zhang H.; Xie J.-J.; Song S.-M. 收藏  |  浏览/下载：58/0  |  提交时间：2013/03/25 Asphericity which affects the manufacturing process and the grinding quantity is an important parameter of optical aspherics. In this paper  the approximation  the least square fitting  wavefront aberration  sag methods are given for the calculation of optical asphericity. The effects of different definitions of optical asphericity are analysed to optimize the process of manufacture. A sag method is presented to solve the best-fit sphere and asphericity for an off-aixs aspheric mirror with a rectangle aperture of 180mm145mm  and polishing quantity and distribution plots are given. The optical manufacturing and testing technology for different choices of best-fit spheres and asphericity are described and analyzed. Therefore  proper definition of optical asphericity which is useful to manufacturing is very important for optical fabrication and test. 2009 SPIE.   Double-swing method used for polishing off-axis aspherical mirrors (EI CONFERENCE) 会议论文 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China Wang P.; Li J.-F.; Xuan B.; Chen X.-P.; Song S.-M.; Chen Y.; Xie J.-J. 收藏  |  浏览/下载：24/0  |  提交时间：2013/03/25 Based on the characteristics of off-axis aspherical surface  the comparison of simulation effects under different parameters is made. In order to achieve optimal parameters  a new method used for polishing off-axis aspherical mirrors-Double-Swing Method (DSM) is proposed in this paper  a high order off-axis rectangle aspherical mirror has been polished by DSM. The final result of profile measurements of 12nm  and the polishing mechanism of DSM is introduced. The mathematical model of the DSM with steady movement state is established.The movement of this mathematical model is simulated in a programming language  RMS is achieved. The result indicates that the method is of practice and has even higher working efficiency and precision. 2009 SPIE.   The synthesis and field emission property of carbon nanotubes on carbon fibers substrate (EI CONFERENCE) 会议论文 Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07, July 8, 2008 - July 12, 2008, Chicago, IL, United states Leyong Z.; Weibiao W.; Jingqiu L.; Yuxue X.; Da L.; Song C.; Haifeng Z. 收藏  |  浏览/下载：21/0  |  提交时间：2013/03/25 Using ferrocene as catalyst precursor  C2H2 as carbon source  carbon nanotubes (CNTs) with uniform density were synthesized on carbon fibers substrate by floating catalyst method. The morphology and microstructure were characterized by field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscopy (HRTEM). The observation showed that the length of CNTs is about 2 m  the average space between adjacent CNTs is about 300 nm and the diameter of CNT is about 45 nm. The less dense "short and stubby" aligned CNTs films should have good electron field emission characteristics. The results of field emission showed that the emission current of CNTs/carbon fibers was 5 A at the field of 2.5 V/m  and the emission current can be 280 A with a field of 7 V/m (the specimen area is 0.25 cm2 and the distance between cathode and anode is 200 m). The calculation based on the F-N plot indicated that the field enhancement factor of CNTs tip is 499122. Using the conductivity and chemical stability of carbon fibers and the uniform and sparse density distribution of CNTs on carbon fibers substrate  the tip predominance of carbon nanotubes can be exerted  and simultaneously the effect of screening effects between adjacent carbon nanotubes on the field emission performance can also be effectively decreased. The CNTs synthesized on carbon fibers substrate has many predominances for the fabrication of cold cathode devices. For example  using the removability of carbon fibers  the cathode of CNTs/carbon fibers can be arbitrarily moved  enlaced or combined to form different patterns  and the cathode of CNTs/carbon fibers can be also fabricated in large size. Therefore  CNTs/carbon fibers may have potential application in field emission displays.   The spectral feature analysis of semiconductor thin disk laser (EI CONFERENCE) 会议论文 Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China He C.-F.; Qin L.; Li J.; Cheng L.-W.; Liang X.-M.; Ning Y.-Q.; Wang L.-J. 收藏  |  浏览/下载：20/0  |  提交时间：2013/03/25 The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of semiconductor disk laser  and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperature. We can see that: with increasing pump power  the thermal effects of the gain material becomes seriously and causes the saturation of carrier lifetime  so the electron-hole pair created in the absorbtion layer have no enough time to rate to one of the wells  and the non-radiative recombination happens in the barrier. When the thermal effects becomes stronger  the chip will not lasing. This phenomenon is from the smaller energy offset between barrier and quantum well. We optimize the original structure design and experimental technology. A non-absorbing AlGaAs layer who is transparent to the pumping and laser wavelength is added to confine the carriers in the quantum wells. At the same time a DBR with double reflecting band is induced to improve the absorbing efficiency of the pumping light. The single QW is replaced by the three narrow QWs  This three QWs structure can add the quantum state of QW  increase the recombination probability of carriers in the QWs and reduce the heat effect. The chemical etch equipment is also improved to control the surface unevenness to be within 50 nm.   Research on animal laser varicose treatment in CIOMP, CAS (EI CONFERENCE) 会议论文 Fifth International Conference on Photonics and Imaging in Biology and Medicine, September 1, 2006 - September 3, 2006, Wuhan, China Zhang L.; Li D.; Lu Q.; Yang G.; Guo J. 收藏  |  浏览/下载：14/0  |  提交时间：2013/03/25 The work on laser varicose treatment carried out in CIOMP  It provides minimal invasion  CAS cooperating with The First Clinical Hospital  often under local anesthesia and intravenous sedation thereby eliminating the need for general anesthesia  Jilin University is summarized. Dozens of animal experiments adopting dog and rabbit samples are made in a long time of several years. Different lasers are used  greatly shortens postoperative recovery term  including long pulse frequency-doubled Nd:YAG(532nm) and semiconductor laser(808nm). Dozens of animal experiments show that laser has good efficacy to occlude the vein vessels. It has precise adjustability and relatively short treatment time only needing outpatient office setting with high cost and effect rate  and it is highly safe with no side effects and no serious complications.   Vacuum annealing effects on properties of ITO films prepared by reactive low voltage ion plating technique (EI CONFERENCE) 会议论文 ICO20: Optical Devices and Instruments, August 21, 2005 - August 26, 2005, Changchun, China Xu Y.; Gao J.; Zheng X.; Wang X.; Wang T.; Chen H. 收藏  |  浏览/下载：8/0  |  提交时间：2013/03/25 With reactive low voltage ion plating technique  ITO (indium oxide doped with tin) films were deposited on glass substrates by using ITO pellet with a composition of 90 wt.% In2O3 and 10 wt.% SnO2 without extra heating. The post annealing process was done in vacuum with different annealing temperature at 100  200  300 and 400C for 2 hours  respectively. The effects of vacuum annealing on structural  optical and electrical properties of the ITO film deposited by RLVIP were studied in detail. The results showed that the crystalline of the film was improved with the higher temperature. The increase of the annealing temperature improved the infrared reflectivity from 30% to 80% over 8-14m of the infrared atmosphere window  and a simultaneous variation in the optical transmission of the visible spectral region occurred. In addition  sheet resistance of ITO films had contrary changing trend with the IR reflectance  as well.   Er3+-Doped lutetium borosilicate glass for optical signal amplification at 1.5 m (EI CONFERENCE) 会议论文 Infrared Components and their Applications, November 8, 2004 - November 11, 2004, Beijing, China Sun J.; Zhang J.; Lu S.; Wang X. 收藏  |  浏览/下载：14/0  |  提交时间：2013/03/25 A new glass of Lu2O3-B2O 3-SiO2-Na2O-Er2O3 system is prepared by the technique of high-temperature melting at different temperatures and the formation range of the glass is experimentally obtained. Effects of the B2O3 content on the infrared spectral properties such as the 1.5 m emission bandwidth corresponding to 4I13/2&rarr4I15/2 transition and the Judd-Ofelt parameter t (t = 2  4  6) of Er3+ ions in the glass has been observed. The glass exhibits big integrated emission cross sections for the 1.5 m emission band. Excellent thermal stability of the glass has been demonstrated using differential thermal analysis. The Er 3+-doped lutetium borosilicate glass is a great candidate for broadband erbium doped fiber amplifiers.