2018 Vol. 47, No. S1
A new method of detecting roundness error of cylindrical inner-hole based on coaxial hollow laser technology was presented. In view of the optical properties of cone lens and structural characteristics of cylindrical inner-hole, a detecting optical system which permits to reflect the detecting beam only once was presented. In the experiment, the roundness error of the cylindrical part was tested, and the test data was analyzed with the least square method. The result shows that the detection accuracy can reach 0.1 m. The method shows the advantages of optical detection technology such as non-destructiveness, noncontact, high precision and thus it can be used to detect the morphology and position error.
2018, 47(S1): 5-9.
doi: 10.3788/IRLA201847.S106002
In this paper, laser polarization detection principle were expounded laser, and a new technical approach for laser fuze to recognized target using different polarized characteristics of different target on laser background scattering were invented. Experimental system were designed, the different objectives polarization test were completed. The test results are that smooth surface of metal objects have high degree of polarization, rough surface of objects have low degree of polarization. The realization scheme of polarization detection laser fuze is proposed, and the target discrimination technology is verified through prototype design.
2018, 47(S1): 10-15.
Laser fuze works in the near-infrared band. Due to its advantages of strong ability of resisting electromagnetic interference, high ranging accuracy and good directivity, near-infrared laser fuze has been widely used as an important type of fuze system. Obtaining the scattering characteristics of the target by analyzing the changes of the infrared light field plays an important role in improving the performance of the infrared fuze. Based on this, a novel dual frequency infrared laser fuze system was proposed. The theoretical calculation of the scattering properties of the infrared light field with different targets and analysis of the physical factors that affect the scattering phase function were carried out. The results show that when the particle size is smaller than the infrared laser wavelength, the scattered light is mainly backscattered. When the particle size is larger than the infrared laser wavelength, the main scattering light is mainly forward scattering. Therefore, a new identification method for different targets was proposed and proved the feasibility and practicability of this method.
2018, 47(S1): 16-22.
doi: 10.3788/IRLA201847.S106004
Aiming at the miniaturization and high performance requirements of laser fuze, a novel driving circuit was designed to drive the pulse laser diode. The circuit used high-speed MOSFET as the switching element to generate a driving pulse with narrow pulse width, short rise time and large peak current for laser diode. A corresponding driving circuit model was established. The effects of supply voltage, energy storage capacitor and damping resistor on the performance of driving pulse were analyzed by simulation and experiment. A driving circuit with the size of 19 mm10 mm was designed and the optimal circuit parameters were selected. The driving circuit provides a driving pulse with pulse width of 8.6 ns, rise time of 4 ns and peak current of 39 A. The design provides an effective improvement of detection performance of laser fuze.
2018, 47(S1): 23-28.
doi: 10.3788/IRLA201847.S106005
The MARMOT(Middle Atmosphere Remote Mobile Observatory in Tibet) lidar had been deployed at Golmud(36.25N, 94.54E), Qinghai Province, for measuring the mesospheric density from 50 to 90 km from August 2013 to October 2015. An improved method for Rayleigh lidar retrieval of the mesospheric density was proposed, by using the TIMED/SABER satellite data at 50 km as the reference value. The results show that the lidar derived densities are consistent with the satellite data. However, both the lidar and satellite measurements of mesospheric densities are mostly lower than the MSIS-00 model, with the largest discrepancies occurred at 75-90 km in winter.
2018, 47(S1): 29-35.
doi: 10.3788/IRLA201847.S106006
The effects of loss and noise(real environments) on the performance of quantum lidar with odd coherent superposition states source(OCRS) was investigeted. The general expression of conditional probabilities and parity photon counting measurement strategies were exploited to derive the mean value of the output signal and its phase sensitivity from the Mach-Zehnder interferometer(MZI). It can be found from the output signal that loss destroys the coherence and further descents the performance of lidar. The numerical calculation shows that the odd and even interference fringes emerge in the whole interference pattern, and the odd interference term which represents the coherence is extremely sensitive to particle loss. The odd coherent states quantum lidar outperforms the performance achieved by the traditional coherent states(CS) lidar only in small loss regimes. However, in the noisy environments, OCRS gives the better resolution and sensitivity than CS in the regions of к0.3 and к0.06, respectively.
2018, 47(S1): 36-43.
doi: 10.3788/IRLA201847.S104001
In order to discriminate crack defects in base material covered by spray coatings, the heat generation pattern of coating crack and substrate crack were investigated when being excitated by low frequency ultrasonic vibrancy, based on theoretical analysis and numerical simulation. The surface temperature varieties caused by coating crack and substrate crack were compared; the turbulence to coating crack thermal wave caused by heat generation of a substrate crack was analysed, and the phase deviation (PD) phenomenon of mixed thermal wave was observed. On this basis, a method to identify cracks in the base material under the spray coating was proposed, which employed phase deviation as the characteristic parameter. Furthermore, experiment was implemented to validate the proposed method, polynomial fitting (PF) and wavelet decomposition (WD) were utilized to improve the time frequency resolution ratio during image processing and reconstruction.
2018, 47(S1): 44-49.
doi: 10.3788/IRLA201847.S104002
Atmospheric correction is one of important steps to obtain the intrinsic radiance of the target for an infrared radiometry system. Traditionally, the mean to calculate atmospheric transmittance and atmospheric path radiance are calculated by an atmospheric radiance transport calculation software. A method based on standard reference direct amending atmospheric attenuation was proposed, which was applied for high precision precision measurement and inversion on a small target. The based principle and procedure of this method were introduced, and then the model of wide dynamic calibration was employed. Radiometric experiments were performed on a mid-wave infrared system with a 600 mm aperture. The radiometry results indicated that the radiance inversion precision for a small target, using the proposed method, is 0.97%-1.03%, while the precision using a conventional atmospheric transport calculation software method is 7.30%-7.36%, which demonstrates that the proposed method provides a high-precision result.
2018, 47(S1): 50-54.
doi: 10.3788/IRLA201847.S104003
In recent years, with the improvement of people's living standard, the rate of obesity was on the rise, and the dangers of obesity to health was rising too, therefore the monitoring of obesity became particularly important. Firstly, the propagation mechanism of near infrared light in the fat tissue was discussed, and the interactions between near infrared light and the fat, muscle tissues such as absorption, scattering and reflection were studied in this research. Then the near infrared spectroscopy information of the fat tissue was gotten by the experiments, whose results demonstrated that 930 nm was the best candidate for measuring the fat tissue thickness, and the intensity of light at this wavelength was strongly correlated with the fat tissue thickness on a large scale. Because of the interference of the muscle tissue and the small dynamic range of light intensity varied with the fat tissue thickness at 1 040 nm, the wavelength of 1 040 nm was not suitable for measuring the fat tissue thickness. It laid a foundation for further and better realization of optical noninvasive fat measurement through this study.
2018, 47(S1): 55-59.
doi: 10.3788/IRLA201847.S122001
The detector cannot detect photon successfully when the signal transmission rate exceeds the maximum detector count rate in high speed quantum key distribution scheme. This leads to correlations in the sifted bit string, and the security is compromised. In this paper, the high speed measurement device independent quantum key distribution based on BB84 protocol with finite detector dead time was analyed and the optimal transmission speed was simulated. Simulation result shows that the sifted key rate raised linearly with the increase of photon transmission rate without consideration of the influence of detector's dead time; with consideration of the influence of detector's dead time, the sifted key rate is no longer raising with the photon transmission rate infinitely and the curve of sifted key rate is distorted. When the transmission distance is 100 km, the correlation between the sifted key rate and detector dead time is approximate to 2.1/10, and the correlation between optimal transmission rate and detector dead time is approximate to 3.3105/.
An approach of double-frequency signal generation and analogue transmission with high inter-modulation distortion suppression was described, which can be widely used for Radio Over Fiber(ROF) system. The approach was mainly based on a Dual-Parallel Mach-Zehnder modulator (DPMZM) and two electrical phase shifters. By adjusting the three biases of the DPMZM, double-frequency signals with high inter-modulation distortion suppression were generated. On the same structure, by adjusting bias of MZM2, which is the sub-modulator of DPMZM, and controlling the electrical drive voltages on the electrodes of MZM2, an analog photonic link with high IMD3(third-order inter-modulation distortion) suppression was realized. From tests, the double-frequency signals with inter-modulation distortion suppression of approximately 30 dB and the analog photonic link with complete IMD3 suppression were validated and proved. The approach reduces the difficulty, complexity, and costs of ROF system, while increasing the stability of ROF system. Experimental results for IMD3 suppression are well matched with the analysis ones.
2018, 47(S1): 68-73.
doi: 10.3788/IRLA201847.S122003
High-order Quadrature Amplitude Modulation (QAM) in a limited bandwidth can transmit more information than either BPSK or QPSK system. Therefore, the technology is widely used in cable communication systems. While optical scintillation affected the high-order QAM system easily. The multi-mode blind signal equalization is used to reduce the influence of scintillation caused by atmospheric turbulence. In simulation, the turbulence channel was modeled by Gamma-Gamma distribution. The constellation of receiving signal shows the different points dispersions under different channel noise situations. Results show that the transmitted signal was primarily affected by multiplicative noise. A 64-QAM experimental system is built to demonstrate the feasibility of the system under real situation.
2018, 47(S1): 74-81.
doi: 10.3788/IRLA201746.S122004
The Brillouin scattering spectrum follows Voigt profile. The existing key parameters extraction algorithm for Brillouin scattering spectrum is easy to introduce errors. To ensure high accuracy in the extracted key parameters, the temperature and strain measurement, a key parameters extraction algorithm for Brillouin scattering spectrum using Voigt profile was proposed. The Voigt profile was calculated using the Gauss-Hermite quadrature, the objective function was determined based on the least-squares method and Voigt profile. Besides the initial guesses obtainment method of key parameters was presented. The objective function was optimized using the Levenberg-Marquardt algorithm. Once the objective function was minimized, the key parameters were obtained. Additionally, another algorithm was implemented, in which the initial guesses were set to some random values within a certain range, then the Levenberg-Marquardt algorithm was used to optimize the objective function. A large number of Brillouin scattering spectra with different values of signal-to-noise ratio were numerically generated and measured. The results calculated by the two algorithms reveal that the probability of convergence of the random algorithm fall within a range of 80% to 90%. The proposed algorithm always converges in all cases. The errors by the proposed algorithm are only 1/1011-1/7 of that by the random algorithm. The computation time by the proposed algorithm is only 1/8-1/3 of that by the random algorithm.
2018, 47(S1): 82-85.
doi: 10.3788/IRLA201746.S122005
Erbium Doped Fiber Amplifier (EDFA) is an indispensable part of the distributed acoustic monitoring system. It plays an important role in improving the transmission distance and the signal-to-noise ratio of the demodulation signal. However, the presence of the EDFAs will bring Amplifier Spontaneous Emission (ASE) noise generated by different EDFAs on the whole system. Using a filter with a bandwidth of 0.2 nm, the influence of ASE noise on the demodulation signal was observed. The ASE noise generated by the power-EDFA has no effect on the SNR of the demodulation signal. However, the ASE noise generated by the pre-EDFA will greatly affect the SNR of the demodulation signal. After adding a filter after the pre-EDFA with center wavelength of 1 550.12 nm and bandwidth of 0.2 nm, the signal-to-noise ratio of the demodulation signal was increased from about 20 dB to 60 dB.
2018, 47(S1): 86-91.
doi: 10.3788/IRLA201847.S122006
In view of the problems such as the low automation degree and low precision in the traditional fiber optic gyroscope(FOG) static north-finding method, the in-depth analysis of the FOG dynamic north-finding principle and algorithm was focused on. The simulation model of FOG dynamic north-finding algorithm with least square method by points was established based on Simulink toolbox in MATLAB, and then the turntable rotation speed and sampling frequency which affected obviously the FOG dynamic north-finding precision, were simulatedly calculated and optimally analyzed as the key consideration. The simulation and calculation results show that, in the case of adopting the proposed parameters, when the turntable rotation speed is 4.5-8.5()/s and the sampling frequency is about 50 Hz, the FOG dynamic north-finding system can reach higher precision. The simulation model and the research conclusions can provide theoretical reference for the design of FOG dynamic north-finding system. Meanwhile, it also provides reference for the theoretical research and concrete realization of the FOG dynamic north-finding system.
2018, 47(S1): 92-98.
doi: 10.3788/IRLA201847.S122007
Fiber Bragg grating strain sensors embedded in composite material are generally coated with polyimide which can operate at high temperature environment with large tensile stress. However, the volume of polyimide coating is influenced by humidity. The humidity influence on fiber Bragg grating strain sensors which were embedded in carbon fiber reinforced composite material was investigated by theoretical analysis, finite element simulation and experimental method. The partition of mesh was optimized to improve the precision of the simulation, and the simulated strain variation of fiber Bragg grating strain sensor caused by relative humidity change was less than 4 . The humidity experiment results were obtained from 10 days continuous tests, and the measured strain variation of fiber Bragg grating strain sensor in carbon composite material was less than 8 with temperature compensation. The simulation and experiment results reveal that the embedded fiber Bragg grating strain sensors coated with polyimide are not significantly influenced by humidity change. The characterizations of embedded fiber Bragg grating strain sensor, including repeatability and linearity were tested and analyzed in tension test. The embedded fiber Bragg grating strain sensors possess good repeatability and linearity.
2018, 47(S1): 99-104.
doi: 10.3788/IRLA201746.S120001
Out-of-band response is a very important parameter of UVFPA detectors. As a wide-gap semiconductor material, AlGaN based ultraviolet detector exhibits excellent performance of the out-of-band response and rejection in ultraviolet detection. Visible blind AlGaN 6408 pixel ultraviolet focal plane arrays (UVFPA) detector was reported, whose spectral response range is 345-363.5 nm. To characterize the out-of-band response of the detector over a wide spectral range, by monochromatic spectral scanning, a response spectrum of the UVFPA was obtained with a wide range from UV to near IR. The result shows that the UVFPA detector has an excellent performance of out-of-band response. The ratio is 1.14% over the whole spectral band from 300 to 1 160 nm.
2018, 47(S1): 105-111.
Traditional imaging limits to the occlusion of the solid medium such as the wall and can not collect the image of the object which is out of sight. Moreover, the speed of light is supposed to be infinite in traditional imaging, so the imaging process is a steady-state light transport and irrelevant to the time of flight of light, which cannot reveal the specific characteristic of object in the light transport. Single-photon imaging is a technology which can detect very weak photon signal and capture the information of distance, intensity and image of objects synchronously. In this paper, a method of transient imaging for hidden object was introduced. In the imaging process, the time of flight of photon was considered as a variable in light transport to realize transient imaging, combining imaging for hidden object with photon counting and using single-photon array detector as a receiver to reconstruct hidden object. Further, this method was demonstrated by simulation. It provides the basic theory and framework for the transient imaging of hidden object using single-photon array detector, which can help to design the imaging system in real world in the future, as well as to achieve a better understanding of the nature of transient imaging for hidden object.
In order to further optimize time and frequency domain characteristics of fast steering mirror (FSM) for image motion compensation and thus to increase the definition of picture taken by moving camera, a control system based on linear extended state observer(LESO), zero phase error tracking control(ZPETC) and Kalman filter was designed. First, mathematical model of FSM driven by voice coil motor(VCM) was established. Next, principles of LESO, ZPETC and Kalman filter were clarified. Finally, experimental research for controlled object was made. Step response curves demonstrate that the settling time reaches 2.5 ms. Besides, compared to proportional-integral-differential(PID) control system, relative error of output converges to zero faster when it is less than 1%. Bode diagram shows that the bandwidth attains 369 Hz, which is more than 1.5 times that of PID control system. Meanwhile, phase lag reduces nearly a half. When disturbance is added, average relative error of the designed system reaches 0.028%, reduced by 75% compared to that of PID control system. Pictures taken by camera illustrate that this control method makes both subjective visual effect and objective evaluation parameters of image improve further.
2018, 47(S1): 119-124.
doi: 10.3788/IRLA201847.S120004
The cutoff frequency of single mode, dispersion and loss of a novel terahertz polyethylene photonic crystal fiber with triangle core were investigated by using the full-vector finite element method (FEM). The results show that the terahertz frequency range of the single-mode is tailored by the cladding pitch, cladding air hole and core air hole diameters. 0.1-5 THz broadband single-mode transmission is obtained and waveguide dispersion is limited in 0.5 ps/(nmkm) for wavelength of 60-450 m, and the transmission loss is 2.67 dB/m at 2.8 THz.
2018, 47(S1): 125-131.
doi: 10.3788/IRLA201847.S120005
The mesh distribution of laser energy and crosstalk points on the photosensitive surface of visible array CCD was observed when it was irradiated by 1 064 nm pulsed laser from a distance of 30 m. It was found that the pitch of adjacent lattice was about 100 m and remained unchanged as the incident laser energy increased or F-number of the front optical system decreased, but the center main spot and the spots at the ambient lattices could enlarge little by little with the decrease of F-number. It was clearly seen that every spot at the ambient lattices was geometric image of optical system's stop when F-number is 2.8. There is no doubt that the novel phenomena are firstly reported and the related research will certainly promote deep investigation on the laser propagation in the optical system and the interaction between laser and material.
KDP is a type of excellent nonlinear single crystal electro-optical material, which is used in high-energy laser systems. However, KDP is extremely difficult to be finished for its particular physical and chemical properties. Magnetorheological finishing (MRF) is considered to be an effective processing method for finishing KDP to high precision at present. But the performance of KDP would decrease obviously if the residual contamination remained after finishing. An active cleaning agent with high-frequency ultrasound technology was put forward to solve the problem. Microscope and white-light-interferometer were employed to assess the effects of cleaning process on KDP surface. The results show that the residual contamination is removed availably, and the surface roughness is improved as well. Additionally, the Raman spectral and laser interferometer analysis indicates that crystal structure and surface accuracy of KDP remain unchanged after cleaning. These conclusions prove that the cleaning method achieves desired result and exhibits a promising prospect of KDP cleaning.
2018, 47(S1): 138-146.
doi: 10.3788/IRLA201847.S117001
The multiple impact equipment of short interval and multiple impact loading is the key equipment to verify the high impact resistance and initiation control strategy for multi-layer penetration fuze in laboratory, the motion law of the moving part under high impact has an important influence on the consistency of acceleration. In view of measurement problem of complex dynamic motion process under multiple high impact, a non-contact measurement method based on high-speed photography and image processing was presented, obtaining pixel coordinate of feature point of the moving part by background difference and feature point detection, combining with the sub-pixel algorithm, further improving the accuracy of measurement. The results of high-speed photography were verified by contrast experiment and dynamic simulation, proving that the method is reasonable and feasible for complex dynamic motion process measurement under high impact, providing support for optimal design of the multiple impact equipment, also enriching the existing methods of complex dynamic motion measurement.
2018, 47(S1): 147-153.
doi: 10.3788/IRLA201847.S117002
Wavelength calibration is an important step for CCD-spectrometers. The accuracy of the wavelength calibration will affect the precision of the measurement results. However, the accuracy of traditional wavelength calibration will be affected by instrument bandwidth and noise. The bandwidth of the instrument will generate the overlapping peaks in the calibration spectrum or cause the peak position shift of double peak. The noise will make inaccurate measurement of peak point. To solve this problem, a simple and accurate wavelength calibration method for CCD-spectrometer was proposed. The automated decomposition algorithm and Voigt line profile model were used to optimize the shape of the calibration spectrum and the precision value of the peak points of each calibration peak could be obtained. Using this method, the influence of bandwidth and noise could be eliminated, especially the overlap peaks could be decomposed into several single peaks, simultaneously, and the process of calibration was greatly simplified. Experiments based on USB4000 spectrometer with mercury-argon calibration light source were implemented. The results show that the proposed method could achieve higher accuracy and the calibration deviation is less than 0.1 nm. Therefore, it is recommended to use this method to calibrate the wavelength of the spectrometer.
2018, 47(S1): 154-159.
doi: 10.3788/IRLA201847.S117003
In order to realize the optical detection of the underwater target, in this paper the optical parameter inversion of the sea surface wave was mainly carried out based on the frequency distribution of the ocean wave. Based on the existing observations and research results of oceanography, the linear superposition based on JONSWAP wave spectrum method was used, combined with the formula of direction function, the height model of ocean waves under different wind conditions was established and the real-time mapping of ocean waves was realized. The simulation results show that the model can better meet the real wave conditions.
2018, 47(S1): 160-165.
doi: 10.3788/IRLA201847.S117004
In order to meet the detection requirement of aerial targets in the complex background based on space-based platform, the motion characteristics of aerial targets in different detection angles and space positions was studied, and the motion model of space-based detection scene was established. This study used the motion characteristics of aircraft in the actual situation, and analyzed the characteristics of the angle of pitching, departure and the rotation of the target, and the modeling simulation of target radiation characteristics was realized. On this basis, an integrated all-attitude motion characterization and parameter analysis system was designed based on space-based platform using MATLAB GUI software platform. Results show that in the medium wave, the radiation intensity in direction angle from 270 to 90 above 90 to 270, when the pitching angle is 90, the strongest radiation at the angle of departure of 0, rotation angle has no effect on radiation intensity. In the long wave, the radiation intensity is the strongest at the angle of pitching 0 and 30, the angle of departure 90, and the angle of rotation 90. The system can evaluate the performance of detection by signal interference ratio, moreover, it can further determine the system indices such as the detection resolution and spectrum. The study provides the technical support for space-based aerial target detection.
2018, 47(S1): 166-171.
doi: 10.3788/IRLA201847.S117005
The space-based missile early warning system has different detection effect in different bands, and it is very necessary to select the appropriate detection band. In this paper, 11 kinds of missile plume spectra were studied and analyzed in the 2-5 m. Many influential factors were considered, such as the plume height from the ground, the atmosphere and cloud radiation, atmosphere attenuation, etc.. Principle of selection is relatively stronger radiation of target, distance of target-to-earth from high to low, wave bands from more to less. The number of bands can be controlled by setting the threshold. Finally, the paper selected bands at the center wavelength of 2.99, 3.06, 3.12, 4.6, 4.62 m. According to matching rules to fit out image that contains the characteristics of the target spectral, and signal-to-noise ratio(SNR) was analyzed for characteristic spectral image and full wavelength image. The results show that when the target reaches a certain height, SNR of characteristic spectral image is higher than that of the whole wavelength image.
2018, 47(S1): 172-181.
doi: 10.3788/IRLA201847.S126001
Dynamic range compression and detail enhancement are two important issues for effectively displaying high dynamic range infrared (IR) images on standard dynamic range monitors. Sophisticated techniques are required in order to improve the visibility of the details without introducing distortions. A novel method was introduced for visualization of IR images. The proposed method was composed of two cascaded steps. In the first step, dynamic range compression of infrared images was posed as an quadratic optimization problem that minimize a cost function. In the second step, the detail was enhanced by an specifically designed exponential factor that provided excellent detail visibility and avoid halo artifacts. The performance of the proposed technique was evaluated using a data set of IR images collected from different operating conditions. The results show that the proposed method is insensitive to features occurring in IR image and yield the most visually pleasing outputs. Compared with other algorithms, it can effectively improve the overall contrast, prevent over-enhancement of flat regions and reduce noise visibility.
2018, 47(S1): 182-188.
doi: 10.3788/IRLA201847.S126002
An image noise level estimation method was presented by using affine reconstruction technique and the calculated noise sample histogram. The watershed-based image segmentation was firstly utilized to divide the noisy image into several homogenous blocks. Then by applying affine reconstruction technique, the noiseless affine image signal and the noise residual image were obtained. Noise samples for the standard deviation values of each segmented patch were calculated from the noise residual image. After that the histogram of estimated noise samples was described to find out the specific noise level interval with the most noise samples falling into. Finally, the image noise standard deviation was computed by the average of noise samples in the selected noise interval. Experiments are implemented to demonstrate the effectiveness of the proposed algorithm. The presented method could produce accurate and reliable estimation results for images with rich textures and edges.
2018, 47(S1): 189-196.
doi: 10.3788/IRLA201847.S126003
In the compressive sensing theory, the robust reconstruction of signals can be obtained from far fewer measurements than those obtained by the Nyquist theorem. Thus, it has a great potential in the onboard compression of hyperspectral images using minimal computational resources and storage memory. In this paper, a compressive-sensing-based hyperspectral image compression method was presented using spectral unmixing. At the encoder, the original image was compressed acquired by spatial sampling and spectral sampling, respectively. Then, the spectral and spatial correlation of the compressed data were studied. To improve the compression performance, spectral linear prediction was used to remove the spectral correlation, and the predictive errors were compressed by JPEG-LS in a lossless manner to generate the final bit-streams. At the decoder, the bit-streams were first decoded to obtain the sampled data. Then, a spectral unmixing technique was employed to reconstruct the original hyperspectral image, which can avoid the defect of conventional compressed sensing reconstruction. Experiments on data from the Airborne Visible/Infrared Imaging Spectrometer sensor show that the proposed algorithm provides better compression performance than JPEG2000 and DCT-JPEG2000 with a lower computational complexity.
2018, 47(S1): 197-205.
doi: 10.3788/IRLA201847.S126004
UAV flying in complex battlefield environment, due to the similar shape and color of the enemy UAV, and the existing algorithms can not accurately identify and classify the UAV of the enemy, resulting in false detection or even mishandling attack. To solve this problem, a feature fusion algorithm based on the combination of the bottom visual features and high-level visual features was proposed to classify the UAV target objects. The algorithm first extracted the underlying visual features and high-level visual features of the target object by using visual feature descriptors and Sparse Auto-Encoder (SAE). Then, the principal component analysis (PAC) method was used to reduce the dimensionality of the global features. Finally, the global feature response was sent to the softmax regression model to complete the recognition and classification of the target object of the UAV. Experiments show that the new algorithm has higher accuracy and robustness compared with the traditional SAE algorithm and the traditional recognition algorithm based on the underlying visual features.
2018, 47(S1): 206-212.
doi: 10.3788/IRLA201847.S126005
Image registration is a key step in image mosaic, image fusion and object localization. Given the problem that the aerial remote sensing images may have the uncertainty in image gray level and may be lack of feature information, a registration algorithm of aerial remote sensing images based on lateral inhibition competition was proposed, Firstly, the bright feature points and dark feature points of the reference image and the under registration image were detected with the basic idea of lateral inhibition competition. Then, the similar nature feature points of two images were combined with feature matching strategy and the matching-points sets was shaped. At last, the image transform model was calculated and the images were registered. A new thinking was provided for image registration. Comparing with the traditional feature registration algorithm, the experimental results show that the proposed algorithm has better registration, the aerial remote sensing images can be registered effective. Some conclusions are obtained through the analysis and explanation of the experimental data, which lay a solid foundation for further research.
2018, 47(S1): 213-218.
doi: 10.3788/IRLA201847.S107001
To achieve nonresonant broadband extraordinary optical transmission (EOT), tapered metallic slits array embedded with rectangular cavities structure was proposed and its transmission properties were investigated using the finite element method (FEM). The results show that tapered metallic slits array embedded with rectangular cavities can achieve broadband and wide-angle enhanced transmission in the infrared and the light is strongly localized enhanced at the slit exits, in contrast with straight slits structure. The phenomenon was described with a transmission line model. In addition, the effects of incident polarization, the entrance width of the slit, and the centers misalignment of the tapered slits on the transmission property were also studied. These results would be helpful for optical signal transmission and the designing near field light harvesting devices with broadband and strong transmission.
