Journals >Opto-Electronic Engineering
Contents
2011
Volume: 38 Issue 5
27 Article(s)
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Research Article
Attack Direction of Laser Based on the CCD Detection
AN Kai, and MA Jia-guang
It is easy to detect the attack direction of laser by using interceptive method, such as quadrant detectors, but there has not been any non-interceptive methods used to detect the direction of attack laser. A stereo vision method without matching is proposed. Two CCD cameras sample points and calculate independently, aIt is easy to detect the attack direction of laser by using interceptive method, such as quadrant detectors, but there has not been any non-interceptive methods used to detect the direction of attack laser. A stereo vision method without matching is proposed. Two CCD cameras sample points and calculate independently, and then the direction of the attack laser is confirmed by data fusion. For an obtained image, sample process starts from the upside row and downmost row simultaneously and orderly until a laser image point is found. The stop condition of the process means that sampling doesn’t have to scan the whole image. Used in non-interceptive laser detection, the method not only can detect the direction of attack laser, but also can satisfy the real-time requirement..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 1 (2011)
Vibration Error Analysis in Satellite-to-Satellite SAL Imaging
LI Jin-ming, HU Yi-hua, LI Jin-shan, and LENG Jiao-feng
Generally, Satellite’s vibration has small amplitude, complex spectrum, uncertain start time and duration, and is difficult to be detected accurately. The vibration’s amplitude and spectrum features are analyzed based on coherent detection of Synthetic Aperture Lidar (SAL). The imaging algorithm theory of SAL is brieflGenerally, Satellite’s vibration has small amplitude, complex spectrum, uncertain start time and duration, and is difficult to be detected accurately. The vibration’s amplitude and spectrum features are analyzed based on coherent detection of Synthetic Aperture Lidar (SAL). The imaging algorithm theory of SAL is briefly introduced. Satellite’s vibration error model is introduced into SAL imaging. SAL’s range and cross-range imaging are closely analyzed by theory and simulation-based method. The various kinds of imaging quality loss corresponding with different start time and duration of vibration are investigated. Then a constructive vibration error compensation method is presented. The results show that the vibration’s frequency below 1 kHz can seriously affect imaging of SAL. The longer duration of vibration, more severe damage is caused on the imaging quality. Different time periods vibration can cause different imaging damage. Extending the length of synthetic aperture or reducing the resolution can suppress the damage of vibration error..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 5 (2011)
Centroiding Algorithm for Over-exposed Stars Based on Edge Gaussian Interpolation
LIU Tai-yang, WANG Shi-cheng, LIU Zhi-guo, and LI Qing-hui
The centroiding problem of stars that suffered by over-exposure was explored and an algorithm based on Gauss plane interpolation with data of edge region was proposed. The Over Exposed Region (OER) was detected first to determine the row (or column) data for calculation, then the interpolation of Gaussian plane with edThe centroiding problem of stars that suffered by over-exposure was explored and an algorithm based on Gauss plane interpolation with data of edge region was proposed. The Over Exposed Region (OER) was detected first to determine the row (or column) data for calculation, then the interpolation of Gaussian plane with edge region data was conducted to gain candidate location result of each row (column). The final confirming of last result was then accessed by a comprehensive integration of results with an OER related weighting scheme. Simulation and results analysis proved high reliability and robust capacity of the algorithm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 11 (2011)
Optical Design of Spaceborne High Resolution Hyperspectral Imagers with Wide Field of View
XUE Qing-sheng
Based on the requirements of high resolution and wide field of view, considering the restrictive off-the-shelf detectors, the design method of split Field of View (FOV) is developed. The principle of split FOV is analyzed. A spaceborne high resolution hyperspectral imager with wide FOV is designed using the method. TheBased on the requirements of high resolution and wide field of view, considering the restrictive off-the-shelf detectors, the design method of split Field of View (FOV) is developed. The principle of split FOV is analyzed. A spaceborne high resolution hyperspectral imager with wide FOV is designed using the method. The hyperspectral imager are composed of a 11.42° telecentric off-axis Three-Mirror Anastigmatic (TMA) telescope and two Offner convex grating spectral imaging system. Ray tracing, optimization and analyzing are performed by CODE V software. The analyzed results demonstrate that the Modulation Transfer Function (MTF) for different spectral band is more than 0.7, which satisfies the pre-designed requirement..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 16 (2011)
Aero-optical Evaluation Method for High Speed Flow
LI Bo, and LIU Hong
An aero-optical evaluation method was presented for the investigation on high speed flow’s aero-optical characteristics. The refraction factor which could denote the aero-optical effects of flowfield was derived from the principle of refraction. The planar stabilities of refraction factor distribution in mean flow and An aero-optical evaluation method was presented for the investigation on high speed flow’s aero-optical characteristics. The refraction factor which could denote the aero-optical effects of flowfield was derived from the principle of refraction. The planar stabilities of refraction factor distribution in mean flow and refraction factor fluctuation in fluctuation flow were statistically estimated. The integrative evaluation was the combination of two statistical planar stabilities. The result shows that the mean flow’s aero-optical effects are mainly caused by the shock wave while the fluctuation flow’s aero-optical effects are caused by turbulence boundary layer. The flow’s aero-optical effects reaches minimum when the angle of incident ray is near 45 degrees. The aero-optical effects grow stronger as the Mach number increases. The aero-optical effects become weaker as the angle of attack increases. The results agree well with the theoretical predictions, and it is practical for engineering application..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 21 (2011)
Finite Element Analysis on the Technology of Large-stroke Deformable Mirror
DU Rong-qing, and ZHANG Xiao-jun
To satisfy the large stroke adaptive optical system required, we presented an analysis of an approach to improve the stroke of the deformable mirror. We discussed the influence function between the structure parameters and the main performance index by using Finite Element Analysis (FEA). In addition, the structure parTo satisfy the large stroke adaptive optical system required, we presented an analysis of an approach to improve the stroke of the deformable mirror. We discussed the influence function between the structure parameters and the main performance index by using Finite Element Analysis (FEA). In addition, the structure parameters of the mirror and actuator in a telescope adaptive optical system were discussed based on the FEA results. The results show that the stroke response of the deformable mirror could be improved with optimizing parameters based on the existing techniques..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 30 (2011)
Planar Hyper Lens with Demagnification for Nanolithography
LI Heng-yi, WANG Chang-tao, and LUO Xian-gang
Nanolithography using hyperlens in planar form and i-line mercury lamp is presented. To obtain patterns with high quality at the imaging plane of hyperlens, lens-photoresist-silver layer structure is employed to avoid the blurring of electric field intensity distribution delivered by the transversal magnetic polarizatiNanolithography using hyperlens in planar form and i-line mercury lamp is presented. To obtain patterns with high quality at the imaging plane of hyperlens, lens-photoresist-silver layer structure is employed to avoid the blurring of electric field intensity distribution delivered by the transversal magnetic polarization features of hyperlens. Moreover，the specific design of mask is employed for compensating aberration of magnification non-uniformity of hyperlens.Numerical simulations demonstrate the ability of nanolithography by this method. About 35nm line width with high contrast is obtained in the light distribution and the geometrical parameters influence is also discussed..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 35 (2011)
Full Color Passive-matrix OLED Display Device with the Plane Structure
ZHENG Hua-jing, JIANG Quan, YANG Gang, and RUAN Zheng
By using the plane structured Organic Light-emitting Diodes (OLED) realize color, a full color 1.9″ passive-matrix OLED has been developed. The display has 128 (×3) ×160 pixels with an equivalent full color pixel size of 240 μm×240 μm, and the size of mono sub-pixel is 190 μm×45 μm. 18 bits gray-scaBy using the plane structured Organic Light-emitting Diodes (OLED) realize color, a full color 1.9″ passive-matrix OLED has been developed. The display has 128 (×3) ×160 pixels with an equivalent full color pixel size of 240 μm×240 μm, and the size of mono sub-pixel is 190 μm×45 μm. 18 bits gray-scale data was transferred from a PC by a Digital Visual Interface (DVI) interface. Then, the driving circuits realize 262 k color mode display. The dual-scan driving technology was used to prolong the lifetime of the OLED display to 5 000 h at the average luminance of 40 cd/m2, and the power consumption of the display was about 300 mW..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 40 (2011)
Error Analysis of the Strap-down North-finder Based on the Fiber Optic Gyroscope
WANG Li-fen, XIE Ying, YANG Gong-liu, and WANG Yan-yong
The static error of the fiber optic gyroscope north-finder includes the drift of gyroscope, incline measurement error, mounting error, position transformation error, and physical quantity error etc. The impact of the various errors on the accuracy of the four- position north-finder was analyzed, and the error model wasThe static error of the fiber optic gyroscope north-finder includes the drift of gyroscope, incline measurement error, mounting error, position transformation error, and physical quantity error etc. The impact of the various errors on the accuracy of the four- position north-finder was analyzed, and the error model was derived specially, and the simulation was carried out based on the study above. Simulation result indicates that the most important impact fact is the precision of the gyroscope, and the influence of the position transformation error and mounting error both are bigger than that of the incline measurement error. It also suggests that the influence of all the error except the mounting error will become serious if the latitude goes high. In the end, the advisable scheme to improve the accuracy of the four- position north-finder is put forward..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 46 (2011)
Camshift Ship Tracking Algorithm Based on Multi-feature Adaptive Fusion
YUN Xiao, and XIAO Gang
Multi-target tracking based on vessel image sequences monitored on waterway is the premise of carrying out the vessel active warning and improving bridge-area ship navigation safety. Accurate tracking results are unable to be obtained by traditional Camshift tracking only based on color histogram under complex weather Multi-target tracking based on vessel image sequences monitored on waterway is the premise of carrying out the vessel active warning and improving bridge-area ship navigation safety. Accurate tracking results are unable to be obtained by traditional Camshift tracking only based on color histogram under complex weather conditions. For this reason, a Camshift ship tracking algorithm based on color, shape and texture multi-feature adaptive fusion is proposed. In this method, the target model is realized by multi-feature adaptive fusion, which increases the reliability of observation and improves the robustness of observation model. When tracking targets, the target model based on fusion is included in the Camshift tracking algorithm. The experimental results show that the proposed tracking algorithm can provide higher correctness and stability than traditional Camshift algorithm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 52 (2011)
High-speed Sampling Technology in Laser Ranging
Lü Ming-ai, LIU Jian, and WANG Jiang
In laser ranging, the very weak echo wave detecting is very important and difficult. In order to improve the aim distance and measuring accuracy, the classic method by using the analog electronic technology completely can’t fit for some application any more. Then, a digital high speed data capture system to detect the In laser ranging, the very weak echo wave detecting is very important and difficult. In order to improve the aim distance and measuring accuracy, the classic method by using the analog electronic technology completely can’t fit for some application any more. Then, a digital high speed data capture system to detect the echo wave was designed which adopted high speed AD unit and FPGA circuit as core devices. At last, the realized system reached 1GHz sampling rate and experimental results showed that it could measure a longer effective aim distance and improve the measuring accuracy highly..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 59 (2011)
Design for Coude Optic-mechanical Structure of Large Aperture Telescope
ZHANG Li-min, MING Ming, YANG Fei, and QIAO Bing
In large aperture telescope optical system, Coude path is very important though it deliver the major optical path to enter in the Coude laboratory below telescope, coupling with the sub-optical system. Coude path is composed of many deflected mirrors, and position relationship among optical elements is important for itIn large aperture telescope optical system, Coude path is very important though it deliver the major optical path to enter in the Coude laboratory below telescope, coupling with the sub-optical system. Coude path is composed of many deflected mirrors, and position relationship among optical elements is important for its image quality. So it’s a key technique to ensure their accurate position relationships. On the basis of system requirement, a kind of tuning mechanisms is designed, including tip/tilt tuning mechanism utilizing semi-kinetic support, Dovetail-groove rail displacement mechanism and fine revolution structure. Each of them is characterized with long stroke and convenient operation. So they not only can assure the accurate position relationship, but also are suitable for adjustment and detect. The whole research technique can be a fine reference to the optic-mechanical system, and has been utilized in actual engineering..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 64 (2011)
Investigation and Design for the Structure of 6 inch F/5.4 Reference Spheresmirror with High Accuracy
TIAN Wei, SHI Zhen-guang, SUI Yong-xin, and YANG Huai-jiang
The surface accuracy of lithography projection objectives is nanometer scale, so the accuracy of the testing interferometer is also needed on nanometer to sub nanometer scale. In the field of high-accuracy optical testing, in order to ensure the measuring precision, the accuracy of the interferometer reference spheres The surface accuracy of lithography projection objectives is nanometer scale, so the accuracy of the testing interferometer is also needed on nanometer to sub nanometer scale. In the field of high-accuracy optical testing, in order to ensure the measuring precision, the accuracy of the interferometer reference spheres mirror should be higher than λ/40. A kind of new mechanical structure of reference spheres mirror was designed. The reference surface deformations of interferometer reference mirror were computed by means of finite element method under gravitational conditions. In that case, maximum Peak to Valley (PV) value is only 4.88 nm and the maximum Root Mean Square (RMS) value is 1.04 nm. At the same time，The PV and RMS surface figure error of reference Spheres caused by ambient temperature fluctuation was achieved. Lens system Modulation Transfer Function (MTF) was calculated by using lens shape Zernike coefficients to evaluate the image quality under gravitational conditions. Results demonstrate that the designed mechanical structure of reference spheres mirror can satisfy high demands of reference spheres mirror. At last, a compensated mechanism driven by difference bolt was designed to compensate some errors..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 69 (2011)
Synthesis and Characterization of Epoxysilane-based Planar Optical Waveguide
XU Zhen-wu, XU Jian, XU Qing-bo, and DONG Jian-feng
Organic-inorganic hybrid optical waveguide materials were prepared by non-hydrolytic sol-gel process, using diphenylsilanediol (DPSD) and gamma-glycidoxypropyltrimethoxysilane (GPTS) as precursors. The planar optical waveguide films were deposited on silica glass substrates by spin-coating. Refractive index, optical abOrganic-inorganic hybrid optical waveguide materials were prepared by non-hydrolytic sol-gel process, using diphenylsilanediol (DPSD) and gamma-glycidoxypropyltrimethoxysilane (GPTS) as precursors. The planar optical waveguide films were deposited on silica glass substrates by spin-coating. Refractive index, optical absorption or transmittance of hybrid films was measured with an Abbe refractometer and ultraviolet-visible-near infrared spectrometer, respectively. The structure characteristic of the films was discussed with their Raman and infrared spectra which measured with Fourier infrared spectrometer and Raman spectrometer. Optical propagation loss of hybrid film at length of 632.8 nm was measured by using of the prism coupled method. The results show that refractive index of the films could be adjusted by controlling the content of DPSD (1.461~1.481). Light transmittances of the hybrid materials are approximately 90% in the visible and near infrared range. Optical propagation loss of hybrid film is about 0.26 dB/cm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 75 (2011)
A Robust Adaptive Zero-watermarking Algorithm in DWT-DCT Domain
ZHOU Ya-xun, and JIN Wei
In order to overcome the limitation of the watermarked image quality degradation due to the some changes of the original image data when embedding watermark in the traditional digital watermarking schemes, a robust adaptive zero-watermarking algorithm based on the combined transforms of the Discrete Wavelet Transform (In order to overcome the limitation of the watermarked image quality degradation due to the some changes of the original image data when embedding watermark in the traditional digital watermarking schemes, a robust adaptive zero-watermarking algorithm based on the combined transforms of the Discrete Wavelet Transform (DWT) and Discrete Cosine Transform (DCT) is proposed. First, the original digital image is decomposed into the appropriate levels of DWT, and the DCT is applied to the obtained wavelet approximation sub-image, and then the DCT AC coefficients are selected adaptively in orders according to the size of the embedded digital watermark and the coefficient difference value. Finally, after the combination of the original binary character watermark and the binary key image which is obtained from comparing the selected DCT AC coefficients, the embedding of zero-watermark is realized by registering to the center of authentication. The results demonstrate that the proposed zero-watermarking algorithm not only ensures the watermarked image quality without distortion, but also has very good robustness against the conventional treatments (for example: noise addition, filtering, JPEG compression, rotation) , and is better than the some reported zero-watermarking algorithms..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 80 (2011)
Shelf-life Identification Method of Different Origin Apples Based on Near Infrared Spectroscopy
LIU Hui-jun, SUN Bin, and CHEN Hua-cai
The shelf-life identification method of different origin apples based on near infrared diffuse reflectance spectroscopy at normal atmospheric temperature was proposed. 20 each of the Fuji apple produced in Shandong and Shanxi were bought from the market respectively, and the spectrum of the samples were measured by theThe shelf-life identification method of different origin apples based on near infrared diffuse reflectance spectroscopy at normal atmospheric temperature was proposed. 20 each of the Fuji apple produced in Shandong and Shanxi were bought from the market respectively, and the spectrum of the samples were measured by the purchase date and after the storage of one week (7d). The spectrum of Shandong apple measured at two times were defined as class 1 and class 2, class 3 and class 4 of Shanxi, the absorbance of 1 420 nm and 1 630 nm increased at different degree after the storage of one week. A few preprocessing was compared, and there was litter difference between the sample spectrum analyze by the Principal Component Analysis (PCA) of two kinds. The top 15 variables of the total contribution rate of 97.78% extracted by PCA were input into the radial neural network, and shelf-life identification of different origin apples based on near infrared diffuse reflectance spectroscopy were built. 20 samples in the four classes were chosen as the predicated set. The recognition rates in the calibration set and prediction set were 100%, and the prediction accuracy of 18 samples was higher than 93%. The result shows that a new method proposed by study indicates the shelf-life of different origin apples rapidly..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 86 (2011)
Study of Oil Spill Detection Technique Based on UV-induced Fluorescence
YANG Jun, QI Hong-xing, XIAO Gong-hai, and ZHOU Pan-wei
A method of an oil spill detection system is discussed which provides reliable, economical, optical, noncontact, hydrocarbon pollution detection technique. System uses the fluorescence wave crest around 360nm as the character of oil spill on the water, which is found through the fluorescence spectra of lubricating and A method of an oil spill detection system is discussed which provides reliable, economical, optical, noncontact, hydrocarbon pollution detection technique. System uses the fluorescence wave crest around 360nm as the character of oil spill on the water, which is found through the fluorescence spectra of lubricating and diesel oil detected through experiments. A proto type is designed and tested. The error which is linearly proportional to the distance can be reduced by moving average. System achieves Micron-level sensitivity for a comprehensive range of oils and can detect hydrocarbon releases in real-time. This system can be used for containing and preventing accidental discharges of hydrocarbon-based pollutants and making early warning of pollution before the environment are damaged. It is a great progress in the study of oil spill detection field..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 92 (2011)
Fiber Coupling Efficiency for Free Space Optical Communication Through Atmospheric Turbulence and Compensation
HAN Li-qiang, and WANG Qi
The received laser beam in a free-space optical communication using fiber-optic components system must be coupled into a single-mode fiber. However, propagation through atmospheric turbulence degrades the fiber-coupling efficiency. Single-mode fiber coupling efficiency of expression as a function of atmospheric turbuleThe received laser beam in a free-space optical communication using fiber-optic components system must be coupled into a single-mode fiber. However, propagation through atmospheric turbulence degrades the fiber-coupling efficiency. Single-mode fiber coupling efficiency of expression as a function of atmospheric turbulence parameters is extended to the oblique propagation scenarios, and the coupling efficiency as functions of turbulence intensity, transmission distance and zenith angle is simulated. To compensate for turbulence effects and improve fiber coupling efficiency, this paper use a novel model-free blind optimization wavefront correction with random parallel gradient optimization algorithm to control deformable mirrors and couple the corrected light into the single-mode fiber, so single-mode fiber coupling efficiency is optimized. The results show that single-mode fiber coupling efficiency is significantly improved..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 99 (2011)
A Bilinear Method for Bundle Adjustment
LIU Shi-gang, WU Qing-liang, PENG Ya-li, and CHEN Jiang
To improve the convergency speed, a bilinear method for bundle adjustment is presented in this paper. The algebraic distance instead of the geometric distance is minimized. The alternate steps where these projective points keep constant (respectively estimated) while the projective matrices are estimated (respectively To improve the convergency speed, a bilinear method for bundle adjustment is presented in this paper. The algebraic distance instead of the geometric distance is minimized. The alternate steps where these projective points keep constant (respectively estimated) while the projective matrices are estimated (respectively kept constant) is proposed. The advantage of the method is that all the images are treated uniformly. It is proved that the method can converge to the minimum. The theory analysis and experiment results show that the proposed method is very efficient..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 103 (2011)
Adaptive Image Enhancement of Streak Tube Imaging Based on Shuffled Frog-leaping Optimization
YUE Mei, GUO Bao-ping, ZHANG Ping, and GUO Xuan
A new kind of adaptive enhancement approach, based on shuffled frog-leaping optimization algorithm and incomplete Beta function, is given to streak tube image of streak tube camera. There is not only the local but also the global information exchange in shuffled frog-leaping algorithm. So the result of exploration is rA new kind of adaptive enhancement approach, based on shuffled frog-leaping optimization algorithm and incomplete Beta function, is given to streak tube image of streak tube camera. There is not only the local but also the global information exchange in shuffled frog-leaping algorithm. So the result of exploration is reliable and the speed of constringency is fast. The adaptive parameters of gray transform function are selected by shuffled frog-leaping algorithm, so it could get an optimization curve and enhance the image. Experimental results show that the proposed algorithm is efficient for streak tube image. Compared with traditional enhancement methods, the proposed algorithm can keep the detail of target in the streak image better, and it is superior to traditional enhancement methods in visual quality..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 108 (2011)
4f Coherent Optic System Denoise Method Based on Fusion of Multiple Spatial Frequency Spectrum Images
XU Xin, TIAN Feng-chun, JI Yan-li, and SONG Jian-wen
To remove the random noise and low-frequency coherent noise in the images of 4f coherent optic image processing system, a method based on fusion of multiple spatial frequency spectrum images is proposed. Firstly, capture the multiple spatial frequency spectrum images of once experiment based on the image copying characTo remove the random noise and low-frequency coherent noise in the images of 4f coherent optic image processing system, a method based on fusion of multiple spatial frequency spectrum images is proposed. Firstly, capture the multiple spatial frequency spectrum images of once experiment based on the image copying character form the lattice structure of spatial light modulators. These images contain the same useful image information and noise with the similar distribution but different values. Then, these images are combined by image fusion algorithm whose principle is approximate to the time-domain cumulative mean method to remove the noise. The theoretical analysis and physics experiments show that the method can remove the random noise and diluted the low-frequency coherent noise well, and almost no harm to the useful image information..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 114 (2011)
A Novel Method for Merging Geoeye-1 Panchromatic and Multispectral Images
YANG Zhi-xiang, XU Jia, and HE Xiu-feng
For most of the traditional pixel-level image fusion methods, the spectral distortion is a common problem in high resolution satellite image fusion. A novel spectral preservation fusion method for Geoeye-1 panchromatic and multispectral image fusion is proposed based on the sensor spectral response. The proposed methodFor most of the traditional pixel-level image fusion methods, the spectral distortion is a common problem in high resolution satellite image fusion. A novel spectral preservation fusion method for Geoeye-1 panchromatic and multispectral image fusion is proposed based on the sensor spectral response. The proposed method has improvement in two parts: the construction of low resolution panchromatic image and the modulation coefficients of spatial detail information. To evaluate the performance and efficiency of the proposed method, some traditional image fusion methods were also used to fuse Geoeye-1 images; and the fusion results of each method were evaluated by qualitative and quantitative comparison and analysis. The results show that the proposed method is better than other methods. It can greatly enhance the spatial detail information and minimize color distortion..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 120 (2011)
An Improved Algorithm for Canny Edge Detection with Adaptive Threshold
TANG Lu-lu, ZHANG Qi-can, and HU Song
To overcome the difficulty of threshold selecting in Canny algorithm, an improved method based on Otsu algorithm is proposed to choose the threshold adaptively and simultaneously. Firstly, guided by the gradient histogram of the test image, all the pixels are divided into three classes. Secondly, based on the improved To overcome the difficulty of threshold selecting in Canny algorithm, an improved method based on Otsu algorithm is proposed to choose the threshold adaptively and simultaneously. Firstly, guided by the gradient histogram of the test image, all the pixels are divided into three classes. Secondly, based on the improved Otsu algorithm, an evaluation function is defined to describe the mean square error among the three classes. Finally, both the high and low thresholds are selected adaptively and independently by searching the maximum values of the evaluation function. Artificial parameter setting is not necessary in this method. Compared with the results from traditional Canny method and Direct Otsu method, the method shows great advantage in extracting the real edges from different images, especially low contrast ones..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 127 (2011)
Eye State Recognition Combining with Radial Symmetry and Circular Hough Transform
XIANG Shu-lan, and YOU Yi
To confirm the pilot fatigue, most of methods are carried out through the analysis of eye states. A new algorithm of eye states recognition was proposed based on combining of radial symmetry transform and circular Hough transform. Firstly, the eye states were recognized based on radial symmetry characteristic of iris wTo confirm the pilot fatigue, most of methods are carried out through the analysis of eye states. A new algorithm of eye states recognition was proposed based on combining of radial symmetry transform and circular Hough transform. Firstly, the eye states were recognized based on radial symmetry characteristic of iris when eyes were open, and then for the images which were not recognized only by radial symmetry transform, the center and radius of iris were determined by circular Hough transform. Comparing the position of iris center located by circular Hough transform and the iris center located by radial symmetry transform eye states recognition in these images could be achieved. This method has been applied to pilot fatigue flight video processing and experimental results show that the proposed algorithm achieved a relatively better eye state recognition result. Average success rate of the proposed method is 94.9%, which meets the needs of application requirements of pilot fatigue monitoring..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 133 (2011)
Subpattern-based Weighted Neighborhood Maximum Margin Criterion for Face Recognition
JIANG Yan-xia, and REN Bo
A Subpattern-based Weighted Neighborhood Maximum Margin Criterion (SP-WNMMC) algorithm is proposed for face recognition. In order to enhance the robustness to facial pose, expression and illumination variations, SP-WNMMC method firstly operates on sub-patterns partitioned from an original whole face image. The contribuA Subpattern-based Weighted Neighborhood Maximum Margin Criterion (SP-WNMMC) algorithm is proposed for face recognition. In order to enhance the robustness to facial pose, expression and illumination variations, SP-WNMMC method firstly operates on sub-patterns partitioned from an original whole face image. The contribution of each sub-pattern can be adaptively computed through the class information of neighborhood. Secondly, WNMMC is adopted in each sub-pattern to extract local features. WNMMC can preserve the local geometric structure of database. The objective function of WNMMC leads to the enhancement of classification capacity by using the linear reconstruction coefficients. Thirdly, for a new face image to be recognized, all the likelihoods in all the subpatterns are fused together for the final recognition result. Experiments show that our method can effectively extract the local feature while preserving the non-linear structures in sub-pattern sets. It can consistently outperform other recognition methods based on Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and WNMMC..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 139 (2011)
An Improved Randomized Algorithm for Detecting Circles Based on Least Square Approach
HUO Jian-liang, ZENG Ling, WANG De-sheng, and ZENG Jun
An improved randomized circle detection algorithm based on least square approach was proposed. Because of the incorrect selection of threshold, a circle is divided into some circles. This algorithm can solve the problem perfectly. First, a randomized algorithm for detecting circles randomly picked four edge pixels eachAn improved randomized circle detection algorithm based on least square approach was proposed. Because of the incorrect selection of threshold, a circle is divided into some circles. This algorithm can solve the problem perfectly. First, a randomized algorithm for detecting circles randomly picked four edge pixels each time and calculated circle parameters. The set of pixels belonging to the circle were obtained. Second, these pixels can calculate new circle parameters, and new pixels belonging to these parameters were obtained. Third, until no new pixel was added, it returned these pixels into the set. At last, we checked whether or not the set of these pixels was real circle. Compared with the original algorithm, the proposed algorithm enhances the stability and accuracy of circles detection..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 5, 145 (2011)
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