Journals >Infrared and Laser Engineering
Contents
2001
Volume: 30 Issue 2
19 Article(s)
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Research Article
Detection of infrared point target filters in varying clutter
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In this paper, an infrared point target detection algorithm based on two filters in spatially varying clutter is presented. The target and clutter model is analyzed correctly, and very small (point) target under spatially varying clutter background is successfully detected with the algorithm, when the target and clutteIn this paper, an infrared point target detection algorithm based on two filters in spatially varying clutter is presented. The target and clutter model is analyzed correctly, and very small (point) target under spatially varying clutter background is successfully detected with the algorithm, when the target and clutter are both moving across the image scene. This method can reduce the cost of computation, track the target in real-time, enhance the SNR, and suppress the clutter effectively..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 96 (2001)
Visual verification system of target feature extraction and dynamic tracking algorithm
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The verification system of target feature extraction and dynamic tracking algorithm includes some modules such as image preprocessing, image segmentation, target feature extraction, feature stability analysis and tracking algorithm testing, etc. and covers many typical algorithms. An optimal set of algorithm for specifThe verification system of target feature extraction and dynamic tracking algorithm includes some modules such as image preprocessing, image segmentation, target feature extraction, feature stability analysis and tracking algorithm testing, etc. and covers many typical algorithms. An optimal set of algorithm for specific target and background can be selected and tested by dynamic tracking..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 99 (2001)
Automatic recognition of vehicle license based on hidden Markov model
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In this paper, a new algorithm to recognize characters in vehicle license plate based on hidden Markov model(HMM) is presented. In the method, two-dimensional hidden Markov model(2D-HMM) is used to recognize chinese characters, and pseudo two-dimensional hidden Markov model(P2D-HMM) is used to recognize English charactIn this paper, a new algorithm to recognize characters in vehicle license plate based on hidden Markov model(HMM) is presented. In the method, two-dimensional hidden Markov model(2D-HMM) is used to recognize chinese characters, and pseudo two-dimensional hidden Markov model(P2D-HMM) is used to recognize English characters and numbers. It is proved that this algorithm can be used to recognize varisized characters with high tolerance to distortion and blur, and its character recognition accuracy is above 94%. It can be put into practical use..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 102 (2001)
New algorithm study and application for target recognition
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A new algorithm called shape size contrast filter-SSCF is described in this paper. The target shape feature is considered and the limitation of size contrast filter with single loop structure is overcome. With this algorithm, the target of specific shape and size can be recognized correctly. The principle and structureA new algorithm called shape size contrast filter-SSCF is described in this paper. The target shape feature is considered and the limitation of size contrast filter with single loop structure is overcome. With this algorithm, the target of specific shape and size can be recognized correctly. The principle and structure parameter determination are introduced here by an example, where the “八” mark on the wafer should be aligned. The advantage of accuracy to recognize targets is proved..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 108 (2001)
Simulative calculation methods of atmospheric transmittance of LWIR under sea and sky background
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Based on original theoretical calculation, the expression of deposit vapor volume in atmosphere under sea background is deduced, and calculation of saturated water vapor pressure in atmosphere is modified. Atmospheric molecule absorption in different height is considered. Spectral transmittance functions of vapor and cBased on original theoretical calculation, the expression of deposit vapor volume in atmosphere under sea background is deduced, and calculation of saturated water vapor pressure in atmosphere is modified. Atmospheric molecule absorption in different height is considered. Spectral transmittance functions of vapor and carbon dioxide are presented respectively. In addition, the influence of ozone is analyzed. Expression of atmospheric transmittance is shown..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 112 (2001)
Ultrashort pulsed laser for multiphoton microscope
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The advanced laser techniques for microscope are based on the femtosecond pulse generation mechanism. Several ideas for multi-color and tunable pulse generation are discussed. The compact ultrafast optical fiber lasers are considered as the second generation of femtosecond lasers for microscopy. The third generation teThe advanced laser techniques for microscope are based on the femtosecond pulse generation mechanism. Several ideas for multi-color and tunable pulse generation are discussed. The compact ultrafast optical fiber lasers are considered as the second generation of femtosecond lasers for microscopy. The third generation techniques such as light propagation control achieved by refractive index distribution in core and clad are promising. The super continuum is generated in 1-m optical fiber by the photonic fiber structure..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 118 (2001)
Technology of laser communication in atmosphere
The history, development and classification of optic communication are introduced. The principle of laser communication in atmosphere, important devices, key technique and open questions are described. The causes of energy attenuation in laser communication through atmosphere are also analysed, and the method to reduceThe history, development and classification of optic communication are introduced. The principle of laser communication in atmosphere, important devices, key technique and open questions are described. The causes of energy attenuation in laser communication through atmosphere are also analysed, and the method to reduce the attenuation is presented. The current situation of laser communication in atmosphere at home and abroad is studied. The development of laser communication in atmosphere in the future is discussed at last..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 123 (2001)
Calculation of laser-induced temperature increment and thermal stress of Al-film reflector
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The planar thermal conduction of Al-film and three-dimentional thermal conduction in K9 glass (substrate) when an Al-film reflector was irradiated by laser beam were analysed. The distribution of temperature and thermal stress in the K9 glass was calculated using finite element method. The influence of reflectivity andThe planar thermal conduction of Al-film and three-dimentional thermal conduction in K9 glass (substrate) when an Al-film reflector was irradiated by laser beam were analysed. The distribution of temperature and thermal stress in the K9 glass was calculated using finite element method. The influence of reflectivity and transmission distance of laser on the temperature increment and thermal stress of the reflector was also discussed. The transmission distance should be chosen appropriately to keep the reflector out of crack..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 128 (2001)
Accurate temperature control of film resistance heater
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The accurate temperature control method uses the ITO thin film to heat up the glass and uses PID to control the heating voltage by the output voltage of A/D circuit board. How to control temperature accurately by PID when the heater's thermal capacity is small is the main point of this paper. The pellicle resistancThe accurate temperature control method uses the ITO thin film to heat up the glass and uses PID to control the heating voltage by the output voltage of A/D circuit board. How to control temperature accurately by PID when the heater's thermal capacity is small is the main point of this paper. The pellicle resistance heater which can work continuously and has high emissivity is primarily developed. Its temperature can be accurately controlled..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 131 (2001)
Research on out-door scene image generation approach under different weather
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Different kinds ofatmospheric media and variation of weather conditions make the generation of out-doorscene image specially complex. In this paper, the influence of atmospheric media indifferent weathers on imaging for out-door scene is analyzed firstly. Then the formulasfor MTFse by sensed time, sunrise time, sunset Different kinds of
atmospheric media and variation of weather conditions make the generation of out-door
scene image specially complex. In this paper, the influence of atmospheric media in
different weathers on imaging for out-door scene is analyzed firstly. Then the formulas
for MTFse by sensed time, sunrise time, sunset time, temperature, wind speed,
relative humidity, solar flux and the formulas for MTFa by visibility distance, path
length are given. The overall MTF is the product of MTFse and MTFaFurthermore, the method of synthesizing image by MTF and the schemetic flow of image
generation are presented. Finally, the simulated images are compared with the gray level
ones captured in different weathers in our experiment, and the results are promising..
atmospheric media and variation of weather conditions make the generation of out-door
scene image specially complex. In this paper, the influence of atmospheric media in
different weathers on imaging for out-door scene is analyzed firstly. Then the formulas
for MTFse by sensed time, sunrise time, sunset time, temperature, wind speed,
relative humidity, solar flux and the formulas for MTFa by visibility distance, path
length are given. The overall MTF is the product of MTFse and MTFaFurthermore, the method of synthesizing image by MTF and the schemetic flow of image
generation are presented. Finally, the simulated images are compared with the gray level
ones captured in different weathers in our experiment, and the results are promising..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 134 (2001)
Discussion of Bayesian method and Dempster-Shafer evidence theory
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At present, Bayesian method and Dempster-Shafer evidence theroy are the primary methods of decision-level identity estimation used in real-time C3I system. The identity is discerned by fusing multiple parametric data obtained by multisensor. In this paper, the basic theory and fusion process of two methods are introducAt present, Bayesian method and Dempster-Shafer evidence theroy are the primary methods of decision-level identity estimation used in real-time C3I system. The identity is discerned by fusing multiple parametric data obtained by multisensor. In this paper, the basic theory and fusion process of two methods are introduced and compared. An example is presented. At last, the development of identity estimation methods is put forward..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 139 (2001)
Mini-leak detection for metal dewar
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Leak rate is one of the key factors that affect the storage life and working life of detector/dewar assembly, and also the major parameter for estimating the vacuum perfection of military dewar. Especially, the mini-leak which is difficult to be probed by conventional leak detection method is the major factor that affeLeak rate is one of the key factors that affect the storage life and working life of detector/dewar assembly, and also the major parameter for estimating the vacuum perfection of military dewar. Especially, the mini-leak which is difficult to be probed by conventional leak detection method is the major factor that affect the producivity of military dewar. In this paper, the methods, basic principle and test results of several kinds of super sensitive leak detection are described. And according to the requirement of military dewar, the corresponding leak detection method for the research and production is selected..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 143 (2001)
Research of photoelectronic detection on confronting stealth attack weapons
The attack weapons made by use of the stealth technology or low visibility technology are main target threat which would be confronted by the aerial defense systems at present or in the 21st century. The stealth weapons can be detected. The conventional long wave but lower frequency radar can detect the threat target oThe attack weapons made by use of the stealth technology or low visibility technology are main target threat which would be confronted by the aerial defense systems at present or in the 21st century. The stealth weapons can be detected. The conventional long wave but lower frequency radar can detect the threat target of low visibility. The laser radar, the photoelectronic detection and the radar component have the ability to detect stealth target..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 147 (2001)
High performance SDH/SONET chip group
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The transmitter consists of MAX3890(synthesizer and clock generator)and MAX3867(laser driver).The total randomjitter is only 3.4 psRMS. MAX3890 can provide a 2.5 Gbps colck to the inputlock of MAX3867 for the second timing of the data signal, and it makes MAX3867 to be theonly systematic jitter source. Its typical systThe transmitter consists of MAX3890(synthesizer and clock generator)and MAX3867(laser driver).The total random
jitter is only 3.4 psRMS. MAX3890 can provide a 2.5 Gbps colck to the input
lock of MAX3867 for the second timing of the data signal, and it makes MAX3867 to be the
only systematic jitter source. Its typical systematic jitter is no more than 50psRMS.
The receiver consists of MAX3866(TIA),MAX3875(restoring circuit of clock and data)and
MAX3885(resolver). Its total random jitter is only 4.6 psRMS, and the
systematic jitter is about 20 psRMS. This chip group has large design abundance
as to the 2.5 Gbps SDH/SONET jitter standard of ITU/Bellcore..
jitter is only 3.4 psRMS. MAX3890 can provide a 2.5 Gbps colck to the input
lock of MAX3867 for the second timing of the data signal, and it makes MAX3867 to be the
only systematic jitter source. Its typical systematic jitter is no more than 50psRMS.
The receiver consists of MAX3866(TIA),MAX3875(restoring circuit of clock and data)and
MAX3885(resolver). Its total random jitter is only 4.6 psRMS, and the
systematic jitter is about 20 psRMS. This chip group has large design abundance
as to the 2.5 Gbps SDH/SONET jitter standard of ITU/Bellcore..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 152 (2001)
1/f noise spectrum test of infrared detector
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The purpose of studying the 1/f noise spectrum of IR detector is to learn its the surface treatment situation and reduce the transition frequency of the 1/f noise spectrum. After briefly introduction of the 1/f noise, the measurement principle of the 1/f noise and the measuring system configuration are explained in theThe purpose of studying the 1/f noise spectrum of IR detector is to learn its the surface treatment situation and reduce the transition frequency of the 1/f noise spectrum. After briefly introduction of the 1/f noise, the measurement principle of the 1/f noise and the measuring system configuration are explained in the paper. Finally, the curves of the 1/f noise spectrum for typical HgCdTe PC/PV detectors are given and the analysis of these curves are made..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 155 (2001)
[in Chinese]
Application of K-L transformation in multispectral image clustering
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Remote-sensing image characterizes terrestrial object by its spectrum and space identity. The CTBT satellite nuclear test verification and a crop assessment could be carried out by use of multispectral image of particular area in different period. Based on K-L transformation, a clustering algorithm to deal with redundaRemote-sensing image characterizes terrestrial object by its spectrum and space identity. The CTBT satellite nuclear test verification and a crop assessment could be carried out by use of multispectral image of particular area in different period. Based on K-L transformation, a clustering algorithm to deal with redundant data between several bands of multispectral images was proposed. A multispectral image of certain nuclear test site and a civilian TM image were processed and analysed. The results indicate that the algorithm is available..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 79 (2001)
LS-Kalman algorithm for passive target location and tracking with bearing-only measurements
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Bearing-only location is a nonlinear state estimation in essence. Classical extended Kalman filter is erratic. In this paper, expressions for the least squares estimation of target location and its variances have been derived by the static estimation theory. Then Kalman filter is used in x, y, z directions respectivelyBearing-only location is a nonlinear state estimation in essence. Classical extended Kalman filter is erratic. In this paper, expressions for the least squares estimation of target location and its variances have been derived by the static estimation theory. Then Kalman filter is used in x, y, z directions respectively to improve the location accuracy. Simulation shows that it is simple and efficient..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 83 (2001)
New stereo precise matching method for free-form surface measurement with computer vision
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A new stereo precise matching method for free-form surface measurement with computer vision at subpixel level was proposed, which combined many algorithms. Firstly, using projection grating, distortion stripes were created on the curve surface. Some points of stripe edges were detected with wavelet transform. Secondly,A new stereo precise matching method for free-form surface measurement with computer vision at subpixel level was proposed, which combined many algorithms. Firstly, using projection grating, distortion stripes were created on the curve surface. Some points of stripe edges were detected with wavelet transform. Secondly, a non-supervisor clustering searching fitting algorithm was discussed. So all of edge points were divided into different groups according to stripe edges, the edge points were fitted by interpolating cubic B-spline, and the fitted curves were recognized and marked. Lastly, corresponding points on every curve were exactly matched based on epipolar constraint, and the coordinates of the corresponding points were calculated. Therefore, the stereo matching at subpixel level for double cameras of converging optical-axis is completed successfully..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 87 (2001)
Multiresolution image matching algorithm using zero-crossing of wavelet transform
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In this paper, an algorithm for image matching which utilizes the wavelet transform was proposed. A binary wavelet radicle was selected and the multiresolution zero-crossing of binary wavelet transform was used as matching primitive. This algorithm used more structure features of the image. The matching strategy from cIn this paper, an algorithm for image matching which utilizes the wavelet transform was proposed. A binary wavelet radicle was selected and the multiresolution zero-crossing of binary wavelet transform was used as matching primitive. This algorithm used more structure features of the image. The matching strategy from coarse-to-fine and strict constraints were used to reduce the searching area. The quality control after matching was carried out also. Experiment shows that the algorithm is reliable and stable in operation, and has high accuracy..
Infrared and Laser Engineering
- Publication Date: Apr. 01, 2001
- Vol. 30, Issue 2, 91 (2001)
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