2017 Vol. 46, No. 11
column
- Invited paper-Super-resolution imaging technology
- Infrared technology and application
- Laser technology and application
- Terahertz technology and application
- Photoelectric device and microsystem
- Photoelectric measurement
- Optical design and simulation
- Optical communication and optical sensing
- Spectrum detection and analysis
- Information acquisition and identification
2017, 46(11): 1103001.
doi: 10.3788/IRLA201746.1103001
Photoacoustic imaging (PAI) or optoacoustic imaging, the modern application of an ancient physical discovery to biomedical imaging, is without doubt one of the most exciting imaging technologies that has drawn increasing attention from biomedical specialists. In PAI, the rich contrast of optical excitation is seamlessly combined with the high spatial resolution and large penetration depth of ultrasonic detection to produce clear images of optically scattering biological tissues. As a complementary imaging modality that surpasses the territory of traditional microscopic optical imaging, PAI has been explored for numerous biomedical studies, and hence enthusiastically embraced by researchers around the globe who have attested to its unique imaging capabilities, namely the deep penetration and functional sensitivity. Not surprisingly, as the market clearly sees the promise, the commercial production of PAI systems has grown apace with the technological advancements and clinical applications. The adoption of commercial PAI in research and clinical settings has however seen difficulties, majorly due to costs, regulatory blocks, and competition with mainstream technologies. Here, from a practical standpoint, a wide range of commercial PAI systems currently available in the market were introduced, their advantages and disadvantages were analyzed, and the design considerations for targeted applications were emphasized. The key technological, logistical, and clinical issues were also discussed that need to be solved to accelerate the technology translations. By doing so, it is hoped that a clearer picture of the future commercialization of PAI for clinicians, researchers, and industrial entrepreneurs will be presented.
2017, 46(11): 1103002.
doi: 10.3788/IRLA201746.1103002
Cell is the basic unit and functional unit of living body. The study of the internal structure and function of living cells is one of the foundations of mastering the essence of life. Therefore, the realtime observation of living cells is of great significance for the development of life sciences. Conventional optical microscopy is limited by the diffraction limits and can not observe the details of biological structures below 200 nm. In the past 20 years, with the rapid development of super-diffraction limit optical theory, technology, devices and fluorescent probes, super-resolution microscopy has become an important method for life science research. However, most super-resolution microscopic methods or measurements take a long time, or are likely to cause photobleaching/phototoxicity, and are severely limited in living cell studies. In this paper, based on the study of fast super-resolution microscopy, the photoactivated localization microscopy and stochastic optical reconstruction microscopy were introduced based on single molecule localization microscopy. The stimulated emission depletion microscopy based on fluorescence non-linear saturated light conversion and structured illumination microscopy based on structured light illumination was also introduced. Besides, the development and application of cell imaging were explored. Finally, an outlook of the future development trend of super-resolution microscopy in living cell imaging was provided.
2017, 46(11): 1103003.
doi: 10.3788/IRLA201746.1103003
A scanning near-field optical microscope (SNOM) based on an apertureless optical probe was presented. The probe had a V shape hollow on its top and coated with metal film. Illumination near-field light (NFL) will emit from the apex of probe when far-field light (FFL) is focused on the hollow. There is a phase difference between collected NFL and FFL, which relates to the distance between probe and sample. The collected FFL can be eliminated using a Glan-Taylor analyzer according to the phase difference. The experimental results show the phase difference of this system is 57. The spatial resolution of SNCOM is less than 12 nm.
2017, 46(11): 1103004.
doi: 10.3788/IRLA201746.1103004
A method of full-field micro strain measurement using digital image correlation was proposed to evaluate the risk of printed circuit board assembly failure induced by stress. It outperformed traditional testing methods based on experiment in terms of full-field strain measurement and location of strain concentration. Experimental method based on three-dimensional digital image correlation and stress loading strategy was designed. The risk of circuit board assembly failure was evaluated by the obtained full-field distributions of principle strain and history curves of strain on selected local areas. High repeatability of the presented method, which was better than 100 , was exhibited by the experiments, allowing the obtainment of the circuit board assembly full-field micro strain distribution. Moreover, areas where strain exceeds rated value can be localized easily and exhibited intuitively. The presented method provides important measured data which can be used to improve the circuit board assembly design, reduce the risk of circuit board assembly failure, and protect the safety of electronic components.
2017, 46(11): 1103005.
doi: 10.3788/IRLA201746.1103005
A method, which can extract the particle size information with a resolution beyond /NA, was proposed. This was achieved by applying Fourier ptychographic(FP) ideas to the present problem. In a typical FP imaging platform, a 2D LED array was used as light sources for angle-varied illuminations, a series of low-resolution images were taken by a full sequential scan of the array of LEDs, and the data were then combined to produce a high-resolution image. Here, the particle size information was extracted by turning on each single LED on a circle, whose radius was chosen according to an expression for the resolution limit. The simulated results show that the proposed method can reduce the total number of images without loss of reliability in the results, and the total number of images can be further reduced by optimizing the aperture overlapping rate.
2017, 46(11): 1103006.
doi: 10.3788/IRLA201746.1103006
Through the analysis of confocal microscope in the imaging process caused by the position, such as optical hardware deviation converge and pinhole position deviation occurring in image distortion phenomenon, a position correction function into interpolation algorithm was proposed for nonlinear distortion image correction and rehabilitation. The convolution neural network based on machine learning technology was applied to improve the quality of image position correction after degradation when training a single image. The five layers of convolution and down sampling to join pooling layer were employed to reduce the order of magnitude in network parameters. The results show that the pooling layer can improve the operation speed significantly and improve the sharpness of the image.
2017, 46(11): 1103007.
doi: 10.3788/IRLA201746.1103007
A real time integral imaging pickup system was proposed using a binocular stereo camera. In the proposed system, the conventional camera array was replaced by the binocular stereo camera for three-dimensional (3D) scene pickup, which made the system simpler. In the system, left view and right view images were first captured by the binocular stereo camera, and the high-resolution depth map was calculated in the graphics processing unit. Then, the depth map and color texture image were used to generate the parallax images of new perspectives in parallax, and pixel mapping algorithm was adopted to obtain the high-resolution elemental image array for the real-time integral imaging display. In the experiment, the resolution of the calculated depth map was 4.25 times more than the depth map acquired by Microsoft Kinect2, the real-time pickup and display for 3D scene can be achieved in case the resolution of elemental image array was 1 920 pixel1 080 pixel, and sub-images was 99. The experiment results demonstrate the effectiveness of the proposed system.
2017, 46(11): 1103008.
doi: 10.3788/IRLA201746.1103008
A batch of super-resolution fluorescence microscopy technologies have been invented to overcome the diffraction limit of traditional optical microscopy. It thereby greatly enhances the capacity of sub-cellular structure investigation. Among these super-resolution microscopy, Stochastic Optical Reconstruction Microscopy (STORM) based on single molecule localization has attracted more and more attention by researchers due to its straightforward principle, simple operation mode as well as super-high resolution. First, the basic principle of single molecule localization was introduced, the design of the light path of STORM was discussed, and the principles of 2D-STORM and 3D-STORM were provided. Then, the development of multi-color imaging as well as correlative STORM and electron microscopy were discussed. Finally, some recent typical researches depending on STORM were presented.
2017, 46(11): 1104001.
doi: 10.3788/IRLA201746.1104001
It was found that when the integration time of the detector was not consistent with the time when the correction parameters were obtained, the correction effect would get worse for the non-uniformity correction method of the infrared focal plane array detectors based on the blackbody calibration. The main reason was that the response of output pixel was nonlinear with integration time, and traditional blackbody calibration methods belonged to single point correction in the dimension of integration time. Aiming at this problem, an adaptive non-uniformity correction method for integration time changing was presented, which used multi-point correction method in two dimensions of radiation flux and integration time, thereby effectively solving the problem. In addition, this method used the actual response data as the calibration data, which can effectively save the parameter space. The mean value of local non-uniformity was used as the evaluation method of the correction effect, and the evaluation method could reflect the local characteristics of the residual after correction. Experimental results show that this method can effectively reduce the non-uniformity caused by the integration time changing compared with the traditional methods, and improves the engineering applicability of the methods based on the blackbody calibration.
2017, 46(11): 1104002.
doi: 10.3788/IRLA201746.1104002
In order to solve the problems in high zoom ratio lens design, a two-stage-of-series zoom lens model was proposed based on optics zoom theory. Therefore, differential zoom equations were deduced and solved to help the lens power assignments, also the cam curve optimization condition and method were proved. In this model, first stage zoom was achieved by the two-part-zoom front part, and the given movement pattern of the compensation lens and the second magnified lens determined the second stage zoom, by which the 100% cooled stop efficiency was assured. Based on this method, a 70x MWIR zoom lens under the requirements of F/4, focal length 6.5-455 mm, HFOV 0.92-58.2, work waveband 3.7-4.8 m was designed, which only used two kinds of infrared materials, consisted of 10 lenses, total length 300 mm, had good image quality and tolerance character.
2017, 46(11): 1104003.
doi: 10.3788/IRLA201746.1104003
A method based on pixel-based fusion method was proposed for infrared dual-band target simulator. The dual-band subwavelength grating instead of optical thin film was used as a filter, only a set of scene generator and projection system was used to complete the dual-band infrared target simulation. This method solved the traditional dual band infrared target simulator's problem of relatively complex structure, high cost and untunable energy ratio. Firstly, the working principle of the method was introduced and its feasibility was illustrated. Then, based on the rigorous coupled-wave theory, subwavelength grating filter's characteristics under different parameters were analyzed. Finally, the design of grating was completed according to the dual wavelength detection needs.
2017, 46(11): 1104004.
doi: 10.3788/IRLA201746.1104004
An athermal mid-infrared imaging spectrometer based on the Offner scheme was designed to meet the requirement of mid-infrared spectrum analysis. According to the solution of the athermal equations, athermal structure could be designed reasonably through reasonable combination of materials with different thermal properties. Method of solving the initial structure and optical software optimization was introduced based on the analysis of Offner structure principle. A push broom imaging spectrometer with 3-5 m spectral range was designed by this method, and its operating temperature range is from -40℃ to 100℃ depending on the achromatic optimization. The spectrometer has good spectral performances, the dispersion spot diameter of which is less than 30 m in the full field of view. The spectrometer's transfer function value is greater than 0.35 at the spatial cutoff frequency of 16.7 lp/mm, and its spectral resolution is less than 15.6 nm.
2017, 46(11): 1106005.
doi: 10.3788/IRLA201746.1106005
Femtosecond laser-induced damage of optical components seriously restricts the development of ultrashort and ultra-intense laser systems with ever higher average powers and peak intensities. In the ultrashort pulse regime, the damage of optical materials is closely related to the nonlinear ionization processes inside the materials, such as the multiphoton ionization, the avalanche ionization, and the decay process of electrons in the conduction band. In other word, the femtosecond laser induced damage in optical components display highly deterministic damage performance. To investigate the laser induced damage inside the chirped mirrors, ultrafast carrier dynamics in Nb2O5/SiO2 chirped mirrors excited by 800 nm, 1 kHz femtosecond laser had been investigated by pump-probe technique. Reflectance of dielectric chirped mirrors was found reduced after pump pulse excitation femtosecond and dozens of picosecond range. The reduction is mainly ascribed to the absorption of conduction electrons inside the Nb2O5 layers in dielectric chirped mirror film, which plays an important role in laser induced damage. To investigate the ultrafast dynamics in dielectric film in detail, the relaxation lifetimes of electrons in the conduction band has been measured as 1.31 ps, 6.88 ps, and 22.34 ps, respectively.
2017, 46(11): 1106001.
doi: 10.3788/IRLA201746.1106001
According to the America's NIF, France's LMJ and Russia's LUTCH device platinum particle detection parameters, a large diameter N31 Nd:glass platinum particle scanning platform was established by using the Nd:YAG laser(10 J, 10 ns, 10 Hz). On this platform, the damage under high power laser irradiation of the inclusion of platinum particles in the large diameter Nd:glass was tested and studied. The morphology of the inclusions in the platinum particles was observed and discussed by using the high resolution optical stereo microscope. Preliminary studies show that Nd:glass produced under normal production conditions does not contain platinum particles when the process of removing platinum inclusions. During production is abnormal, it is possible that platinum inclusions are contained inside the Nd:glass. The scanning parameters established in this paper can effectively detect invisible inclusions, and timely and accurately reflect platinum process conditions to ensure the normal production of Nd:glass.
2017, 46(11): 1106002.
doi: 10.3788/IRLA201746.1106002
Within ICF laser system, many independent laser beams are required to be positioned on target with a very high degree of accuracy during a shot. Optical elements that are capable of moving a laser beam on the target must meet the pointing error budgets. The beam positioning error budgeting was provided. The stability allocation was developed for evaluating the performance of support systems when they were subjected to multiple sources of excitation that can cause motions of optical elements during the alignment procedure and before a shot. The vibrational stability design considerations of support systems on the fundamental frequency, ambient random vibration, and modal damping was discussed. The superstructures of optical elements were the relatively large and massive hybrid structure of reinforced concretes and steel frames or vessels. While the reinforced concrete portions provided optical elements stability, the steel portions afforded design flexibility. Finite element analyses of response of broadband ambient random vibration were performed to evaluate the vibrational stability design of support systems. Measurement on broadband ambient random vibration and beam positioning error in target area of SGⅢ was described. The measurement result show that its support systems meet the design requirements and these information can be used on similar ICF laser system.
2017, 46(11): 1106003.
doi: 10.3788/IRLA201746.1106003
As a passive optical cooperative target, the laser retro-reflector is an important part of the laser ranging system. The laser retro-reflector for low earth orbit satellites, provides services in large laser incident angle range, and need to ensure that the error introduced by array structure must be controlled in a certain range. In order to ensure the high precision of laser ranging, most of laser retro-reflectors array structure are hemispherical. In this paper, taking HY-2 satellite laser retro-reflector as an example, the main technical parameters, such as the far-field diffraction distribution, relative effective reflection area distribution, distance correction error distribution and comprehensive precision of laser ranging were analyzed theoretically. The civil TROS1000 mobile satellite laser ranging system was uesd to HY-2 satellite laser retro-feflector, completing laser ranging experiment. The measurement results show that laser ranging accuracy is 1.1 cm, theoretical analysis accords with the experimental results. It marks that the laser retro-reflector of HY-2 satellite has excellent performance and has guiding significance for the future design of laser satellite retro-reflector.
2017, 46(11): 1106004.
doi: 10.3788/IRLA201746.1106004
The polarization characteristic of objects is an inherent characteristic, depending on the external and internal structure of targets as well as the incident angle. Therefore, the measurement of leaf moisture content was researched with polarization information. The research process was divided into the following five parts:Establishing the laser polarization imaging measurement system, calculating the polarization degree of targets, measuring the actual moisture content of leaf, establishing a mapping model between polarization degree and leaf moisture content, and validating the mapping model. According to the target and environment characteristics, the devices and steps of experiment can be chosen and adjusted. The polarization degree can be measured by the method of extracting grey-scale value of the image. Moisture gradient processing was used to measure the actual moisture content of leaf. The mapping models between polarization degree and leaf moisture content were established in the first to third orders based on statistical method. Their stabilities and predictive abilities were compared to analyze their applicable conditions, which provide a theoretic foundation of leaf moisture content measurement with polarization information. The result shows that the polarization degree increases progressively with the moisture content rising from 15%to 75%. The mapping relationship was obvious in case of the high moisture content, while it was insignificant in case of the low moisture content.
2017, 46(11): 1106006.
doi: 10.3788/IRLA201746.1106006
A novel structure of high electro-optic conversion efficiency semiconductor laser with composite waveguide was presented. Because of the AlxGa1-xAs waveguide layer with Al component step distribution, the electro-optic conversion efficiency of the device was high. Due to the optimal design of distribution of resistivity and band, the series resistance of the semiconductor laser was reduced while resulting in the improvement of electro-optic conversion efficiency without reducing the optical power. Based on the theoretical analysis and software simulation, the mechanism of the electro-optic conversion efficiency of the composite waveguide was analyzed. In the condition that the laser width was 6 m and the cavity length was about 1 000 m, the material composition distribution was optimized, and a step of the composite waveguide laser could achieve maximum electro-optical conversion efficiency. The results show that the series resistance of the semiconductor laser with composite waveguide is reduced from 3.51 of the conventional laser structure with conventional waveguide to 2.67 , and the electro-optic conversion efficiency is increased from 54.7% to 69.5% at 900 mA.
2017, 46(11): 1106007.
doi: 10.3788/IRLA201746.1106007
Coherent hole-burning effect in four-level N-style atoms vapors with level transitions was discussed. The absorption spectrum was in detail studied through density operator motion equations, Laplace transformation and quantum regression theorem. In the model two coupling light and one saturated light were adopted to interact. The features of the optical hole-burning were investigated via various adjusting parameters in two optical routing:one was that the two coupling lights co-propagated with the probe light but the saturated light was opposite, and another was that they all propagated on the same direction. And the calculation results were analyzed with the dressed states theory. At most six coherent hole-burning could be simultaneously observed. The depth of the coherent hole-burning could be changed by adjusting the reference parameters and the Rabi frequency of the saturated laser. The positions of the coherent hole-burning could be changed by modulating the Rabi frequency of the probe light. The understanding of the coherent hole-burning was deepened by these reslut.
2017, 46(11): 1125001.
doi: 10.3788/IRLA201746.1125001
In order to get different harmonics output of frequency multiplier, a 170 GHz and 340 GHz frequency selective network based on Compact Suspended Microstrip Resonators(CSMRs) filter was designed. The design met the multi-frequency requirements of systems, and the cost was reduced and the system integration degree was increased. In the simulation, the 170 GHz and 340 GHz probes were designed respectively. CSMRs low-pass filter was introduced to increase the isolation degree of 170 GHz and 340 GHz bands. The waveguide height was decreased, the cutoff frequency of the WR.2.8 waveguide was increased below 300 GHz. The measurement module was back-to-back of Selective Network. The simulation results show that CSMSRs filter has S11-18 dB between 20 GHz and 180 GHz,S12-20 dB between 266 GHz and 520 GHz. The back-to-back module S11 is better than -15 dB at 170 GHz and 340 GHz bands, and two ports isolation degree is better than 30 dB. Measurement results show that S11-10 dB and transmission loss is better than 1.2 dB at 150-185 GHz. S11-10 dB between 306 GHz and 355 GHz, and transmission loss is 2 dB, two ports isolation degree is 10-60 dB.
2017, 46(11): 1125002.
doi: 10.3788/IRLA201746.1125002
An automatic recognition algorithm was proposed for recognizing objects concealed on the edge of human body in an image, which was scanned by THz human security system. First, the pretreatment methods, with binarization, filtering, filling, and morphological corrosion and expansion operations, were used to transfer the original THz image into a binary image, whose outline coordinates was later extracted by clockwise contour tracking algorithm. Then, the combinative application of circular template detection and non-minimal, non-maxima suppression algorithm were applied to calculate and select out all the convex and concave points in the extracted profile coordinates. Finally based on the grouping features of these adjacent convex and concave points, together with their distance constraints, the recognition of the edge objects(Objects covered the contour of human, etc.) could be realized. The experimental results, of testing 500 images of different people with different objects hiding on different edge position taking by the THz human security system, show that this algorithm represents quick identification and strong robustness, having the distinct advantages of strong anti-noise ability, high recognition speed and precision, and also it can match well the recognition accuracy of security system to achieve the system's resolution limit by adjusting proper parameters of the algorithm.
2017, 46(11): 1125003.
doi: 10.3788/IRLA201746.1125003
The design of a 0.22 THz sub-harmonically pumped mixer circuit was demonstrated. The circuit was based on anti-parallel pair of planar Schottky diodes from the CETC 13 with the co-simulation of electromagnetic(EM) software and circuit software. The conversion loss was measured at the fixed intermediate frequency(IF) of 10 MHz. The double sideband(DSB) conversion loss is less than 15 dB in the range of 175 GHz to 235 GHz, the bandwidth is 60 GHz. The best DSB conversion loss is 8.5 dB at 196 GHz. The measured result was well with the simulated result. The DSB equivalent noise temperature of is 1 200 K at 216 GHz with the local oscillator(LO) power of 5.7 mW.
2017, 46(11): 1125004.
doi: 10.3788/IRLA201746.1125004
Terahertz time-domain spectroscopy(THz-TDS) is a new spectroscopic measurement technique based on ultra-fast femtosecond laser technology. THz-TDS technology has been applicated in material detection widely due to its good penetration and safety. In this paper, a method of indentifying transgenic soybean oil with THz-TDS technology was proposed. The methods of the Principle Component Analysis(PCA) and Support Vector Machine(SVM) were based on spectral analysis in the terahertz(THz) range. First, the absorbance spectrum was extracted from the original THz time-domain spectra data of the sample, and then imported into the model of PCA-SVM as an input source import. The utilization of the dimension-reduced data in PCA-SVM model can recognize the validation set accurately, and the transgenic soybeans can be accurately identified. The research results show that THz-TDS technology can identify the transgenic soybeans rapidly and nondestructively, and which could be widely applied in field of food safety inspection.
2017, 46(11): 1125005.
doi: 10.3788/IRLA201746.1125005
Terahertz back scattering properties is a very important index to represent the target's scattering ability of terahertz. Paraboloid occupies an important position in practical applications, but the correlational studies on 2.52 THz target back scattering properties still remain untouched so far. The back scattering measurement experiments on paraboloid with diameter of 50, 60, 70 and 80 mm based on measurement system were conducted. The roughness of paraboloid was 3.2, 6.3, 12.5 m and so on. The MATLAB software was used to deal with the data and the target back scattering properties curve was got. The controlling variable method was used to study size and roughness effects of target terahertz back scattering properties. Target back scattering properties curve dropped slowly as it grew in size, and the lug boss nearby 3 was becoming more and more obvious. The signal waveform of measuring angle edge was observed by the oscillograph which proved the signal was available. Back scattering experiment results show that the maximum measurement dynamic range is 22 dB and the maximum measurement error is about 0.15 dB.
2017, 46(11): 1120001.
doi: 10.3788/IRLA201746.1120001
The injection efficiency of the readout circuit is an important factor that determines the performance of ultraviolet(UV) focal plane array detectors. Based on the equivalent model of the gallium nitride(GaN) based p-i-n structure solar blind UV detector and the capacitor feedback transimpendance amplifier(CTIA) readout circuit, the injection efficiency of photo-generated carrier of the detector was analyzed, then the expression of injection efficiency was obtained. The relationship among injection efficiency and integration time, the equivalent resistor and capacitor of UV detector, the gain of amplifier in CTIA was analyzed. The result indicates the gain of amplifier in CTIA is one of the crucial importance controllable factor that can affect the injection efficiency. Meanwhile, higher injection efficiency can be obtained by improving the gain of amplifier in CTIA. Several amplifiers with different gain were presented, and the CTIA structure readout circuits were made up by using these different amplifiers. A chip was designed and fabricated by using 0.35 m 2P4M mixed signal CMOS process. The ultraviolet detector was individually connected to the CTIA readout circuit with different amplifier gain and the test was carried out. Then the theoretical analysis result of injection efficiency was compared with the testing results. It indicates that the theoretical analysis of injection efficiency agrees well with the actual experimental test result.
2017, 46(11): 1120002.
doi: 10.3788/IRLA201746.1120002
Most photonic crystal lens based on square or triangular lattice usually uses high refractive index materials such as Si or SiO2. And the study on such lens has been focused on the infrared wavelength range. With the development of the visible light communication technology, the research of Sun-flower self-focusing lens with low refractive index materials in visible band becomes very meaningful. To meet that requirements, self-focusing lens based on Sun-flower shaped graded PC was proposed. Firstly, by comparing the convergence intensity of this proposed lens between TE-polarized and TM-polarized mode, the convergence effect of TM polarization was superior to the convergence effect of TE polarization. Then self-focusing flat lens based on TM mode Sun-flower graded PC was designed. The beat length of the flat lens was given by the simulation of optical field transmission. The layers of the flat lens were optimized, and the best number of the layers was 22. In the end, the influence of the number of columns was discussed. The results show that the intensity decreases as the number of columns reduces. It has great guiding significance to make optical integrated devices with high-performance convergence effect, short focal length and small volume.
2017, 46(11): 1120003.
doi: 10.3788/IRLA201746.1120003
Convex blazed grating is one of the key elements in hyperspectral imaging spectrometers. Generally, the effective wavelength coverage of blazed grating is not broad enough to meet the need of imaging spectrometer for grating's diffraction efficiency. To extend the observation band of imaging spectrometer, in which the convex blazed grating was designed and optimized. A case study of 0.4-2.5 m band Offner type imaging spectrometer, single-order and dual-order dispersive structures of convex grating were researched. Partitioned blazed grating and dual-angle blazed grating were used to improve the diffraction efficiency in the range of a broadband. The groove shape of two types of dual-blazed gratings with different dispersive structures was optimally designed, and the diffraction efficiency was calculated by the method of scalar theory and finite element analysis. According to the signal-to-noise ratio(SNR) of the instrument, different types of grating were proposed to meet different requirements of imaging spectrometer.
2017, 46(11): 1117001.
doi: 10.3788/IRLA201746.1117001
Traditional platform seeker can directly obtain the LOS rate by its physical tracking loop, while the strapdown seeker cannot. Losing the ability to directly measure the LOS rate, the strapdown seeker need digital calculation methods to obtain the LOS rate. To solve the problem, the LOS rate estimation model was established. Considering the strong nonlinearity of the estimation model, the strong track cubature Kalman filter(STCKF) was used for the LOS rate estimation. Based on the typical launch conditions of small air-to-surface missile, the trajectory simulation was done to verify the validity of the estimation algorithm. Simulation results showed that, after capturing the target during terminal phase, the seeker can quickly eliminate filter initial error and accurately track the real LOS angles and LOS rates. To verify the feasibility of the filter output as guidance information, Monte Carlo method was used under typical random disturbances of missiles with semi-active laser strapdown seeker. The results of 1 000 shooting show that the guidance precision to stationary target is 0.58 m(CEP), and to move target is 0.84 m(CEP), which meet the accuracy requirements of precision guided weapons.
2017, 46(11): 1117002.
doi: 10.3788/IRLA201746.1117002
In order to describe the polarized bidirectional reflectance distribution function of the paint material more accurately, a double-Gauss polarized bidirectional reflectance distribution function(BRDF) was modeled and simulated which based on the micro-facet assumption. Relative to the previous models, it contained non-Lamb and polarized diffuse reflection based on Rahman-Pinty-Verstraete function. Several experiment groups of polarized BRDF in the plane of incidence of painted surfaces, such as white, matte white, pearl white paint, and the paint on the back of a cd, were measured by the polarization multi-spectral imagery based on Liquid Crystal Variable Retarders(LCVR) at 476 nm. Then, the parameters of model were inversed step by step using the least square method from some experimental data. The inversion results were consistent under many initial conditions, which indicated the obtained parameters were the global minimum. Finally, the model parameters obtained were simulated. The simulation results prove that the simulated intensity and DOP of reflection of painted surfaces fit in the measured appropriate values very well, especially for the polarized diffuse reflection. This model can be applied in classification and recognition of material and scene simulation.
Scattering characteristics of atmospheric haze particles, main ingredients particles of PM2.5 were studied, ammonium sulfate and carbonaceous aerosol particles were taken as typical example. By the T matrix algorithm, the non-spherical particles of ammonium sulfate and carbonaceous aerosol particles were analyzed, including the ellipsoid particles(major to minor axis ratio, a/b=1/2,1/3,2/1), cylindrical particles(diameter to length ratio, D/L=1/2,1/3,1/1,2/1) and chebyshev particles(polynomial n=2,deformation parameter =-0.1,0.1). Corresponding scattering, absorption and extinction efficiency factor changing with the shape and the size parameter were given. Study results show that, for ammonium sulfate particles, if size parameter was less than 1, efficiency factor tendencies of different shape particles were similar, if size parameter was greater than 1, scattering and extinction efficiency factor increased with the size parameter and then decreased with oscillation, and absorption of ammonium sulfate particles were weak. For carbonaceous aerosol particles, if size parameter was less than 2, efficiency factor tendencies of different shape particles were similar, if size parameter was greater than 2, efficiency factor increased with the size parameter and soon decreased slowly and smoothly, and carbonaceous aerosol particles had strong absorption of light. The analyzing results can be used for optical monitoring and detection of haze particle,improve the ability of science and technology supported environmental pollution prevention.
2017, 46(11): 1117004.
doi: 10.3788/IRLA201746.1117004
High precision on-orbit geometric calibration is an indispensible step for space-borne laser altimeter, and which is the foundation for effective application. Considering the geometric calibration method of foreign Geo-science Laser Altimeter System(GLAS) loaded on Ice cloud and land Elevation Satellite(ICESat), an algorithm of satellite laser altimeter geometric calibration was proposed, which used the ground infrared detectors to capture the laser signal transmitted from the satellite. Experiment was carried out using ZY3-02 satellite, which was equipped with domestic first laser altimeter for earth observation. The result shows that the ground infrared detectors can effectively capture the laser signal transmitted from the satellite, the geometric calibration method can eliminate the pointing angle systematic error and improve the height accuracy of laser footprint dramatically. After geometric calibration, the absolute planimetry accuracy can be improved to 15.0 m, and the vertical accuracy is about 1.09 m and a small amount of points even better than 0.5 m according to the experimental region of North China using high accuracy DEM as referenced dataset. Although the disparity of accuracy is clear compared with GLAS, the conclusion can provide a reference for the optimization design, data processing and application of the subsequent domestic laser altimetry satellite.
2017, 46(11): 1117005.
doi: 10.3788/IRLA201746.1117005
The full pose measurement of industrial robot was valuable to robot assembly and robot calibration. In order to decrease the influence of ambient light and expand the target movement space, an active target was designed, and a method of the target calibration based on monocular vision was proposed. The initial pair was selected to enhance the accuracy of the translation vector which was decomposed from essential matrix. Then, images were added one by one and they all were used in the bundle adjustment to compute the high accuracy of 3D structure in the whole scene. Further, the points of the calibration board was adopted as the scale factor, and all the information was transformed into metric. The experimental results demonstrated that the 3D reconstruction precision is less than 0.035 mm, and the method could satisfy the requirement of stereo target calibration. Besides, the robot pose is effectively identified, and the position accuracy is improved by 37%.
2017, 46(11): 1118001.
doi: 10.3788/IRLA201746.1118001
Single convex lens can image objects outside of the focus length, there are a variety of problems, such as different forms of aberration and low resolution. The larger the aperture is, the lower full field MTF is. Multiple lenses are used to correct aberration. The liquid crystal spatial light modulator and micro scanning optical wedge were proposed to realize high resolution imaging with the single lens. It is suggested to use Zygo interferometer to measure single lens with Zemax software simulation wavefront, the Zernike polynomials was applied to describe the distortional wavefront, the conjugate grayscale map was drawn to load in the liquid crystal spatial light modulator and calibrated wave aberration. The optical wedge of 21 was rotated to complete 22 micro scanning. Four low resolution images, through Keren registration and structure-adaptive normalized convolution algorithm, ultimately were synthesized into a high resolution image. The image resolution is promoted to 1 348 LW/PH at MTF50, which proves its effectiveness.
2017, 46(11): 1118002.
doi: 10.3788/IRLA201746.1118002
The atmospheric aerosol is one of the most important factors leading to the global climate change and air quality problems, it is very meaningful to detect the global atmospheric aerosol by satellite. By the joint retrieval of the multi-angle spectral polarimetric information of atmospheric aerosol, the influences of earth surface reflection can be elimated and the accurate detecting outcome is gotten. Thus it is quite urgent to study the integrated optical instrument with the ability to detect multi-angle spectral-polarimetric information of target. The optical system of multi-angle imaging spectropolarimeter was designed, the fore telescope was composed of multi mini-lens, which realized the multi-angle detecting in range of 60long the orbit. The spectroscope system was a common Offner imaging spectrometer. The analysis of imaging quality shows that the MTF of middle waveband at Nyquist frequency is higher than 0.8, and the spot diagrams are all smaller than the Airy disk. All indexes satisfy the commands of system. This optical system is compact in size without any moving part, and can realize the detection of multi-angle polarization state, spectral information and intensity of target.
2017, 46(11): 1118003.
doi: 10.3788/IRLA201746.1118003
NA1.35 immersion lithography lighting system is the core of the very large scale integrated circuit device. In order to satisfy the high resolution requirement of lithography exposure optical system, aspheric lens could be added to decrease the lenses number and increase the energy usage ratio. To solve disadvantages of processing difficulty and low control accuracy of aspheric lenses, the optimization control and testing method of aspheric surface were proposed. By optimizing the aspheric shape to guarantee steradian as well as aspheric inflection point, processing and texting control range could be also satisfied. The illumination system had the largest number of module coupling lenses. By optimization of aspheric lenses, number of lenses decreased from 12 to 9, and energy utilization increased about 25%. In addition, prosperities of NA consistency, image telecentic rate, dispersion spot diameter and distortion were improved, which satisfied the exposure energy requirements on the mask surface of the optical system. So, the aspheric control technology had good processability and detectability.
2017, 46(11): 1122001.
doi: 10.3788/IRLA201746.1122001
In the visible light communication system, the light source has a double function of illumination and communication. As the size of the room and the indoor environment is different, it is inevitable that there will be somewhere with less light irradiation or the light is weak. These places are likely to become a communication blindzone, which will greatly affect the quality of the communication. In order to solve the shadow effect, a rational layout of the light source is needed. Based on 4 m4 m3 m room model, four LED array was adopted as indoor lighting. A single LED light source was considered as a lambert illuminant, which obeyed the Lamber tradiation model. Through formula and software simulation analysis, it was known that when the size of LED array was 99 and the distance from LED array to the edge of roof was 0.4 m and the spacing between the LED light source was 0.03 m, the illumination distribution was most uniform in the horizontal plane of 2.25 m from the roof on the premise of meeting the international standard of indoor lighting. And the uniformity of illumination is 90.4% in the 4 m4 m receiving plane. The model of layout of light source array can be extended to any size of the room in this paper, which provides a feasible solution for the layout of the indoor office lighting source.
Considering that for traditional single-pulse Brillouin Optical Time Domain Reflectometer(BOTDR) system, Brillouin signal is weak and the performance improvement is limited, a Golay pulse coding BOTDR system with Avalanche Photo Diode(APD) detector and local-heterodyne detection was proposed. The coding and decoding principle of Golay code in applying to the system and the principle of local-heterodyne detection were analyzed. The restriction of Stimulated Brillouin Scattering threshold in optical fiber on the coding length of the system was discussed. The mathematical expression of signal-to-noise ratio was deduced and the relationship of signal-to-noise ratio with APD multiplication factor and coding length was studied. The expressions of the optimal multiplication factor of APD and the optimal coding length were obtained, respectively. The MATLAB simulation results show that the optimal value of APD multiplication factor and the optimum coding length exist for this specific system with a bandwidth of the APD detector of 500 MHz, and the peak power and pulse width of 50 mW and 100 ns. The determination of optimum coding length of the system depends on not only the shot noise and thermal noise power, but also the Stimulated Brillouin Scattering threshold of optical fiber. With the APD optimal multiplication factor of 5 and the optimal coding length of 128 bits, the signal-to-noise ratio at the end of 25 km ending fiber increased by 26.42 dB compared to that of traditional single-pulse system, and temperature and strain resolution of 1.60℃ and 35.48 are achieved, respectively.
2017, 46(11): 1122003.
doi: 10.3788/IRLA201746.1122003
Based on the high demand for all optical control and all optical switches in optical communication network, the Raman gain induced resonance control of whispering-gallery-mode optical micro-cavities was investigated theoretically and experimentally. Theoretical analysis shows that Raman gain can compensate cavity loss and change the coupling regime of micro-cavities system. As a result on-resonance transmission in the micro-cavities system can be controlled without any mechanical movement. In experiment fiber taper coupled silica micro-toroid system was studied. Raman gain was pumped with an ultra-low pump power of 560W, with this Raman gain the fiber taper coupled micro-cavity system was turned from deep under coupling regime to critical coupling regime and the on-resonance transmission of the 1 545.7 nm signal light was turned down by 13.5 dB.
2017, 46(11): 1122004.
doi: 10.3788/IRLA201746.1122004
In the process of space laser communication and networking, in order to achieve a satellite terminal for the physical beam access to a plurality of satellite terminals, thereby enabling a satellite to achieve data distribution, routing, switching and other networking functions with multiple satellites, the multi-user physical access method in the process of satellite laser communication acquisition and tracking was studied. Based on the theory of multi-beam forming ability and multi-beam forming of liquid crystal optical phased array, a new type of multi-user access method was designed. The core of this method was to realize the access to multiple terminals by using multi-beam generation and control ability of liquid crystal optical phased array. The position information of the beam in the far field and the diffraction efficiency and energy loss during the process were simulated to verify whether the scheme met the requirements of the space laser communication terminal. The simulation results show that the diffraction efficiency of the access process is greater than 80%, energy loss less than 1 dB, the results display that the proposed method is effective and feasible.
2017, 46(11): 1123001.
doi: 10.3788/IRLA201746.1123001
Shenmai injection is compound traditional medicine and widely employed in adjuvant therapy of cancer patients for improving the patient's life. The interaction of Shenmai injection with human serum albumin(HSA) in physiological buffer(PH 7.4) was investigated by fluorescence spectroscopy and UV-Vis absorption spectroscopy. These results have significant importance for understanding the pharmacological action pesticide effect of Shenmai injection. Shenmai injection can effectively quench the intrinsic fluorescence of HSA and the results shown that the quenching mechanism was a dynamic process, which was further proved by the UV-Vis absorption spectroscopy. The binding constant KA at different temperatures(296, 303, 310 K) were obtained from Modified Stern-Volmer analysis of the fluorescence quenching data. The thermodynamic parameters were calculated by Van't Hoff equation(△G0, △H0, △S0). It indicated that the hydrophobic interactions play an important role in the interaction of Shenmai injection and HSA. In addition, the binding process was spontaneous. Furthermore, the synchronous fluorescence spectra showed that the maximum fluorescence peak of tyrosine residues changed which meant the binding of Shenmai injection to HSA mainly acting on tyrosine residues and the interaction can induce the microenvironment and conformation changes of HSA.
2017, 46(11): 1123002.
doi: 10.3788/IRLA201746.1123002
Raman spectroscopy has been more and more frequently used for pesticide residue detection research in recent years, but the development of sample pretreatment technology is relatively lagging behind. In the study, a rapid method had been developed for the determination of imidacloprid residue in cucumbers with the application of Raman spectroscopy technology and Quick Easy Cheap Effective Rugged and Safe(QuEChERS) sample preparation. Three batches of cucumber samples (the concentration of imidacloprid was within the range of 0.2-5 mg/kg) with different preparation steps(acetonitrile extraction, dehydrate extraction, and fading removing impurity) were chosen as experimental objects. Confocal micro Raman spectrometer was utilized with a 780 nm laser to collect three batches of samples of Raman spectra. Six quantitative prediction models of imidacloprid residue were established based on PLS and PCR methods. The results showed that in addition to the PCR model of the samples by two steps preparation, the residual predictive deviation(RPD) of the other five models was higher than 3. The samples which were only extracted with acetonitrile got the best modeling effect. The correlation coefficient of the calibration set and the prediction set were all above 0.99. The root mean square error of prediction(RMSEP) of PLS method was 0.148 mg/kg, and the RPD was 5.52, which obtained the highest precision of the six predictive models. The results could provide a strong basis for the following-up studies.
2017, 46(11): 1126001.
doi: 10.3788/IRLA201746.1126001
In order to realize the high precision positioning of the mobile robot, a new hybrid positioning algorithm based on VLC was established, the theoretical analysis and experimental verification were investigated. First, according to the advantages and disadvantages of the traditional RSS position algorithm and AOA position algorithm, the RSS algorithm was improved in the paper. Using the relationship between the signal strength and the angle rather than the distance, a hybrid positioning algorithm model was obtained. Then the positioning algorithm was analyzed theoretically in the actual implementation process mainly from the angle of measurement in order to achieve the target parameters. The feasibility of the algorithm was verified by the experiment and the measurement data was obtained. Finally, the experimental data was analyzed to observe the positioning accuracy. The experimental results show that the localization accuracy of the proposed experiment is 6.11 cm, which is less than 10 cm. Besides, compared with the other two kinds of positioning algorithm, the algorithm had high precision, low cost and high feasibility.
2017, 46(11): 1126002.
doi: 10.3788/IRLA201746.1126002
Terahertz imaging was new trend of space optical remote sensing imaging field. However, the resolution of terahertz imaging was difficultly raised, restricted by current level processing and manufacturing technology. The improvement method for terahertz imaging quality was presented to raise the quality of terahertz image. Firstly, the multi-observation stagger terahertz images were received, the target spectrum response ranges was terahertz. Then, the multi-observation images were norm optimization constrained and filtering enhanced. Finally, the higher resolution of terahertz image was reconstructed by multi-observation low resolution original terahertz images. The experimental result showed that target edge was more continuous after being processed by the proposed method. Besides, the background noise on original low resolution Terahertz image was constrained. The evaluation index of image quality was increased, which meant that the proposed method is better than conventional methods. The detail information of processed image was enhanced and then quality of the original terahertz image was improved.
