Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All
Search Results: 1 - 10 of 100 matches for " "
 Page 1 /100 Display every page 5 10 20 Item
 Physics , 2001, DOI: 10.1080/09500340110090846 Abstract: We discuss advantages of using non-classical states of light for two aspects of optical imaging: creating of miniature images on photosensitive substrates, which constitutes the foundation for optical lithography, and imaging of micro objects. In both cases, the classical resolution limit given by the Rayleigh criterion is approximately a half of the optical wavelength. It has been shown, however, that by using multi-photon quantum states of the light field, and multi-photon sensitive material or detector, this limit can be surpassed. We give a rigorous quantum mechanical treatment of this problem, address some particularly widespread misconceptions and discuss the requirements for turning the research on quantum imaging into a practical technology.
 Journal of Communications , 2009, DOI: 10.4304/jcm.4.8.533-545 Abstract: Free Space Optics (FSO) is now a well established access technology, better known for its robustness in transmitting large data volumes in an energy efficient manner. However the BER performance of a FSO ground-link is adversely affected by cloud coverage, harsh weather conditions, and atmospheric turbulence. Fog, clouds and dry snow play a detrimental role by attenuating optical energy transmitted in terrestrial free-space and thus decrease the link availability and reliability. We measured the time variation of received optical signal level during continental fog and dry snowfall over a link distance of 80 m. We perform a detailed analysis of the continental fog and dry snow attenuation results and further characterise them by presenting some useful attenuation statistics and also showing their comparison with the corresponding measured density values collected by a particle sensor device. We propose also an empirical relationship between temperature, relative humidity and optical attenuation values for the continental fog case based on standard curve fitting technique.
 Sensors , 2013, DOI: 10.3390/s130100334 Abstract: Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of optical aberrations. The direct visualization of the photoreceptor cells, capillaries and nerve fiber bundles represents the major benefit of adding AO to retinal imaging. Adaptive optics is opening a new frontier for clinical research in ophthalmology, providing new information on the early pathological changes of the retinal microstructures in various retinal diseases. We have reviewed AO technology for retinal imaging, providing information on the core components of an AO retinal camera. The most commonly used wavefront sensing and correcting elements are discussed. Furthermore, we discuss current applications of AO imaging to a population of healthy adults and to the most frequent causes of blindness, including diabetic retinopathy, age-related macular degeneration and glaucoma. We conclude our work with a discussion on future clinical prospects for AO retinal imaging.
 物理学报 , 2006, Abstract: The uncooled IR thermal imaging technology with its wide applications in military, medical and industrial areas has been an active topic in international research. Thermal imaging based on optical readout bi-material microcantilever array is a new concept in methodology. In this paper, a new kind of bi-material micro-cantilever unit with multi-fold legs and interval gild structure is designed and its thermal and thermo-mechanical performance are analylized. A 100×100 microcantilever array is fabricated as a FPA (focal plane array), and by using this FPA, a thermal image of a room-temperature body (human body) is successfully detected. The NETD (noise-equivalent temperature difference) is about 200mK.The experimental results are well accordant with the thermal analysis of the microcantilever unit.
 Physics , 1999, DOI: 10.1016/S0168-9002(99)00619-1 Abstract: The development of gaseous detectors has been exciting again since the appearance of a MicroStrip Gas Chamber(MSGC) in 1988, which is made using a micro-electronics technology. These days lots of variations of the advanced gaseous detectors are being intensively studied in the world. We have developed the two-dimensional MSGC having a 10 cm square detection area and the ultra fast readout system for a real time X-ray imaging. The MSGC was made using Multi-Chip Module (MCM) technology, and has a very thin substrate of 17 $\mu$m, lots of thin anodes and back strips both with 200 $\mu$m pitches. This enables us to get fast digital X-ray images with recording both the timing and an energy of each X-ray photon. In addition, an intermediate gas multiplier has been realized using a capillary plate having a conductive surface of a capillary. The MSGC combined with the conductive capillary plate can be steadily operated with a high gain under intense irradiation. Here we also report new approaches of X-ray crystal structure analyses using timing information obtained by the MSGC.
 刘扬阳,吕群波,谭政,裴琳琳,李伟艳,王建威 - , 2018, DOI: 10.13700/j.bh.1001-5965.2018.0376 Abstract: 摘要 为实现有效载荷具备上载软件在轨定义多功能、软件可控多功能、参数可重构的软件定义微纳卫星需求，需要突破传统卫星平台和传统光学相机的设计局限，开展基于微纳卫星的软件定义下新型计算光学成像载荷技术研究。充分考虑有效载荷的软件和硬件两者之间联合设计可能存在的发展空间，分析了亚像元信息、卫星平台参数、光学系统参数、探测器参数、噪声、大气对图像数据处理，特别是超分辨率重建的影响。根据各个影响因素的物理机制分别建立物理模型和误差模型，作为重建方法的先验信息，将这些有利于超分辨技术的先验信息约束应用于相机设计过程，使得相机获取的图像可以很好地匹配超分辨方法。该方法可以提升视觉分辨率和实质分辨率，同时保持对噪声的抑制能力，并有可能降低传统相机的结构尺寸和研制难度。研制实现集超分辨成像、动态范围增强成像、视频成像等软件智能可控的多种成像处理模式于一体的通用型计算光学成像相机，将对航天产业提供更大的灵活性和增值空间，为未来智能卫星航天技术研究与快速创新提供一种可行的方案。Abstract：In order to accomplish the software-defined micro-nano satellite demands, which includes that its payload functions and parameters could be reconstructive and controllable by uploading software as needs, we have to break through the design limitations between traditional satellite platform and ordinary optical camera, and one new type of optical imaging camera technology is developed based on software-defined micro-nano satellite here. We gave full consideration to the possible development of joint design space between the software and the hardware of the payload. Then we analyzed the influence of sub-pixel information, satellite platform parameters, optical system parameters, detector parameters, noise and atmosphere on image data processing, especially the super-resolution reconstruction. We established the physical model and the error model according to the physical mechanism of each factor, as priori information of the reconstruction method.We applied these prior information constraints in favor of super-resolution to the design of the camera, enabling the images captured by the camera to match the super-resolution method very well. This method can simultaneously improve visual resolution and substantial resolution while maintaining the ability of suppressing noise, and may reduce the size and development difficulty of traditional cameras. We have developed a general purpose computing optical imaging camera, which integrates the super resolution imaging, dynamic range enhanced imaging, video imaging and other multi intelligent controllable imaging modes. Finally we have completed the related camera integration, testing and experiment.
 Remote Sensing , 2013, DOI: 10.3390/rs5031204 Abstract: We present the results of a project to develop a proof of concept for a novel hyperspectral imager based on the use of advanced micro-optics technology. The technology gives considerably more spatial elements than a classic pushbroom which translates into far more light being integrated per unit of time. This permits us to observe at higher spatial and/or spectral resolution, darker targets and under lower illumination, as in the early morning. Observations of faint glow at night should also be possible but need further studies. A full instrument for laboratory demonstration and field tests has now been built and tested. It has about 10,000 spatial elements and spectra 150 pixel long. It is made of a set of cylindrical fore-optics followed by a new innovative optical system called a microslice Integral Field Unit (IFU) which is itself followed by a standard spectrograph. The fore-optics plus microslice IFU split the field into a large number of small slit-like images that are dispersed in the spectrograph. Our goal is to build instruments with at least hundreds of thousands of spatial elements.
 YongZhong Wang Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-3249-6 Abstract: In order to realize omnidirectional real-time detection and awareness in thermal infrared (IR) region, a kind of biomimetic miniature IR imaging detection system (BMIRIDS) has been successfully developed. It is classified as a long wave IR(LWIR) system and a mid-wave IR(MWIR) one. The former consists of a LWIR fish-eye lens and a LWIR focal plane array (FPA)-biomimetic electronic module, the latter consists of a MWIR fish-eye lens and a MWIR FPA-biomimetic electronic module. Both can provide complete hemispherical staring field of view, and have the capability to determine target bearings, to remove all stationary scene clutter and only detect moving targets, to sense targets range and their velocity. The capability closely approximates the vision process performed in nature by biological sensors. Furthermore, an additional biomimetic module block has been integrated into BMIRIDS. The module block imitating the function of human vision produces the logarithmic brightness image, and enhances the target image outline by virtue of the Roberts gradient difference. The logarithmic transform permits expanding the dynamic range of optical incidence without saturating the electric circuit, and makes the image more suitable for watching. DSP and FPGA perform the aforesaid vision functions that are advantageous to detect and track targets. Therefore, BMIRIDS can perform more powerful real-time signal and image processing on the resulting image data than the ordinary previous systems mainly by the aid of “software-only” processing. Because BMIRIDS has a 2π-steradian (sr.) staring field-of-view, two of such systems opposed to one another would provide a complete view of space around the sensor platform. In addition, its low power consumption makes itself meet the manifold platforms’ needs. The practice has proved that BMIRIDS can truly realize “omnidirectional” “real-time” situation awareness and dynamic information acquirement. By virtue of biomimetic technology, some limitations of the current photoelectric equipment have been broken and a new type of IR equipment has been developed.
 电子与信息学报 , 2002, Abstract: The subimaging target recognition system of infrared rosette scanning is the main optimal terminal guidance system, however, the resolution of the imaging space is not high. Based on the optimal controlling rule of scanning parameter, this paper proposes the phaseshift parameter controlling method which is performed through shifting the phase and overlaping the multi-frame phase diagrams. Thus, high resolution of imaging space under the condition of high speed, nice efficiency is achieved. The experimental results of DSP system show that this technology improves the image resolution of the system effectively.
 Giuseppe Galloro World Journal of Gastrointestinal Endoscopy , 2012, DOI: 10.4253/wjge.v4.i2.22 Abstract: A thorough endoscopic visualization of the digestive mucosa is essential for reaching an accurate diagnosis and to treat the different lesions. Standard white light endoscopes permit a good mucosa examination but, nowadays, the introduction of powerful endoscopic instrumentations increased ability to analyze the finest details. By applying dyes and zoom-magnification endoscopy further architectural detail of the mucosa can be elucidated. New computed virtual chromoendoscopy have further enhanced optical capabilities for the evaluation of submucosal vascolar pattern. Recently, confocal endomicroscopy and endocytoscopy were proposed for the study of ultrastructural mucosa details. Because of the technological contents of powerful instrumentation, a good knowledge of implemented technologies is mandatory for the endoscopist, nowadays. Nevertheless, there is a big confusion about this topic. We will try to explain these technologies and to clarify this terminology.
 Page 1 /100 Display every page 5 10 20 Item