Panoramic imaging has been closely watched as one of the major technologies of AR and VR. Mainstream panoramic imaging techniques lenses include fish-eye lenses, image splicing, and catadioptric imaging system. Meanwhile, fish-eyes are widely used in the big picture video surveillance. The advantage of fish-eye lenses is that they are easy to operate and cost less, but how to solve the image distortion of fish-eye lenses has always been a very important topic. In this paper, the image calibration algorithm of fish-eye lens is studied by comparing the method of interpolation, bilinear interpolation and double three interpolation, which are used to optimize the images.
This paper described implementing the shadowless space by two kinds of methods. The first method will implement the shadowless space utilizing the semblable principles used in the integrating sphere. The rays from a built in light source will eventually evolve into a uniform lighting through diffuse reflections for numerous times, consider that the spherical cavity structure and the inner surface with high reflectivity. There is possibility to create a shadowless space through diffuse reflections. At a 27.4m2 area, illuminance uniformity achieved 88.2% in this model. The other method is analogous with the method used in medical shadowless lamps. Lights will fall on the object in different angles and each light will generate a shadow. By changing the position distribution of multiple lights, increasing the number of light sources, the possibility of obtaining shadowless area will gradually increase. Based on these two approaches, two simple models are proposed showing the optical system designed for the shadowless space. By taking simulation software TracePro as design platform, this paper simulated the two systems.
With the VR(Virtual Reality) technology becoming a hot spot nowadays, one of the key technology--panoramic imaging technology is particularly important. This paper simply introduces various types of panoramic imaging technology, and compares the advantages and disadvantages of the hyperboloidal and paraboloidal catadioptric panoramic imaging system in principle and other aspects. The mathematical models of the hyperboloidal and paraboloidal system is established, and the related system is also designed.
The structure of main lens - Micro Lens Array (MLA) - imaging sensor is usually adopted in optical system of light field camera, and the MLA is the most important part in the optical system, which has the function of collecting and recording the amplitude and phase information of the field light. In this paper, a novel optical system structure is proposed. The novel optical system is based on the 4f optical structure, and the micro-aperture array (MAA) is used to instead of the MLA for realizing the information acquisition of the 4D light field. We analyze the principle that the novel optical system could realize the information acquisition of the light field. At the same time, a simple MAA, line grating optical system, is designed by ZEMAX software in this paper. The novel optical system is simulated by a line grating optical system, and multiple images are obtained in the image plane. The imaging quality of the novel optical system is analyzed.
Augmented reality(AR) technology is becoming the study focus, and the AR effect of the light field imaging makes the research of light field camera attractive. The micro array structure was adopted in most light field information acquisition system(LFIAS) since emergence of light field camera, micro lens array(MLA) and micro pinhole array(MPA) system mainly included. It is reviewed in this paper the structure of the LFIAS that the Light field camera commonly used in recent years. LFIAS has been analyzed based on the theory of geometrical optics. Meanwhile, this paper presents a novel LFIAS, plane grating system, we call it "micro aperture array(MAA." And the LFIAS are analyzed based on the knowledge of information optics; This paper proves that there is a little difference in the multiple image produced by the plane grating system. And the plane grating system can collect and record the amplitude and phase information of the field light.
Space Laser communication is a new technology in recent years of optical communications, optical antenna is a
communications front receiving system, compose of the optical antenna receiver, optical fiber coupling lenses. Optical
antenna to receive as much as possible the signal light from the target of free space, In this paper, 10.6μm wavelength of infrared light for communication wave, we use spherical mirror and aspheric lens combination of the system, Design of
large diameter concave mirror to collect more laser energy, After another spherical convex mirror reflection again to
aspherical lens, then coupled into the fiber. The aspheric lens can be a good feature to correct aberration, so this design
has less transmission loss and high coupling efficiency. Using Zemax software, we setting reasonable energy analysis
and image quality evaluation, design spherical mirrors and aspherical refractive lenses optical system, has good optical
performance and economy, can be apply on the atmospheric Laser communication the receiving device.
In some special circumstances, some dynamic infrared target need to be detected and identificated on the static
background, This paper presents a correlation identification device based on spatial light modulator for infrared imaging
system, a 4F Fourier transform system added to infrared imaging system, The images captured by infrared camera is
loaded onto the input plane of 4Fsystem in real time using spatial light modulator, After a Fourier transform lens and the
digital image transform of its spectrum pattern, in this spectrum plane a special device is placed, and the device is
pre-proseecing through the background of the target then made into the matched filter, Thus, once again through another
Fourier transform lens to do the inverse Fourier transform, When there is a specific dynamic infrared target in the
background, the image loaded on the spatial light modulator will be different, the output plane will produce significantly
different output signal, Thus, in a very short period of time to complete the dynamic target recognition. This design can
transformed infrared image into coherent lignt information processing, it can improve recognition speed and reduce the
identification error, to do parallel multi-channel target recognition.
The conducting mesh are used in many infrared-imaging windows, it can provides anti-frost, anti-fog, or electromagnetic
wave attenuation functions. In this paper, the influence of conducting mesh for infrared optical system discussed base on
Fourier optics principle. The performance evaluation for image including optical system transmission, modulation
transfer function and point spread function. Through the mesh transmission function of Fourier transform calculate and
analysis, then show the light intensity distribution behind mesh. Given and calculate per rectangular pupil hole function
of the mesh, to discuss value changes of Modulation Transfer Function with mesh. So the conducting mesh parameter
design and optimize could according to these analysis results. In same time, this paper put forward an example of the
mesh design parameters.
In digital holographic disc storage, in order to achieve accurate data quickly read and write, and reduce the bit error rate,
it is necessary to make pixel 1:1 match between spatial light modulator (SLM) and charge coupled device (CCD).
However, how to make the Fourier lens precision assembly and achieve pixel match is a difficult problem. In this paper,
based on the Moire fringe of precision measurement technology, a method was to put forward because some Moire
fringe appearance can indicate the location error of machine parts and magnification of lens, on the point of angle and
cycle analysis of Moire fringe, this problem can be solve. Experiment showed that use of this method the pixel 1:1 match
between SLM and CCD achieved. The raw bit error rate of SLM reached 1.5x10-4 and 2.5x10-4 for mask.
This paper focus on a novel collinear lens system with annulus mirrors for holographic disc driver, both information
beam and reference beam are use same laser beam. The expanded and parallel laser beam, center part of it as the
information beam then through Fourier transform lens, the beam around center part as a reference beam. On this axis, the
ring reference beam reflected by two annulus shaped mirrors, then became a convergent beam, together with the
information beam which through the first Fourier transform lens then produce holographic pattern to be write into the
holographic disc behind of them, this lens system with two mirrors made the angle between information beam and
reference beam more wide, can improved the multiplex level of holographic storage. Pair of Fourier transform lens with
advance performance is designed in this paper.
A pair of cascade lenses, a Fourier-transform lens and an imaging lens, is the key component in a volume holographic data-storage system (HDSS) for writing in and reading out the information in holographic recording material respectively. For a high-density holographic data-storage system, performances of these lenses are critical. In order to obtain precise input and output information, and reduce the bit-error rate in the retrieved data, the accurate pixel matching between the whole high-resolution page of SLM and CCD must be ensured. To meet these requirements, in this paper the design of this lens is discussed in detail. In this paper we designed the lenses of unsymmetrical structure and compact profile, and the maximal image distortion of the lens less than 0.01%, and the MTF value at the spatial frequency 40 LP/mm greater than 0.5 over the whole view-field. Other aberrations such as spherical aberration, field curvature, comatic were well corrected. The lens can realize pixel matching between 1024x768 of SLM and CCD. Furthermore, the effect of the manufacture accuracy of the lens on its image quality was analyzed, based on which the optimum parameters and manufacture/assembly tolerance are given.
The recent research on high-density, large-capacity, nonvolatile holographic storage in photorefractive crystals, carried out at Beijing University of Technology, is reviewed in this paper. A batch thermal fixing technique was developed to overcome the volatility of a large number of multiplexed holograms, which has also proved to increase the effective dynamic range of crystals, hence to increase the storage density. The key of this technique is determination of the inter-batch optical erasure time constant that is much longer than the convenient (intra-batch) erasure time constant of the crystal. Disk-type storage is proposed to increase the degree of spatial multiplexing, so that the whole volume of the material can be used for storage, and the capacity increases remarkably. Incorporating batch thermal fixing into holographic disk storage yields to a track-division thermal fixing (TDTF) scheme for holographic disk storage to overcome the volatility of information and increase the storage density and capacity as well. Analyses and experimental results on a high density of 50 bits/μm2 (10 Gbits/cm3) show that high-density huge-capacity mass storage, indicated by storing 1 tera-bits or more data in a single crystal of reasonable size, can be achieved by means of TDTF holographic disk storage scheme.
The batch-thermal fixing scheme was combined into holographic disk storage, for the first time to our knowledge, yielding to a track-division thermal fixing scheme (TDTF), in order to increase the storage density and overcome the volatility of the holographic memories. As a specific batch-thermal fixing scheme, the concept of TDTF scheme was described in this paper. Three principal holographic time-constants of a photorefractive crystal for TDTF scheme were measured, based on which an appropriate exposure-time sequence was calculated and applied to record multiple holograms. The disk mount has been designed and finely manufactured, consequently, the reposition accuracy of the crystal disk can meet the requirement after the crystal experienced off-line thermal fixing. 5000 images, each contains 768×768 pixels, divided into 4 tracks , have been stored in a disk-shaped 0.03wt% Fe doped LiNbO3 crystal using TDTF scheme. The samples of retrieved holograms showed approximately equal diffraction efficiency and good fidelity. The Experiment resulted in a high areal density of 50 bits/μm2 and volume density of 10 Gbits/cm3.