Ground-Based Airglow Imaging Interferometer (GBAII) is functioning as a key instrument for passive remote sensing to detect information such as wind speed, temperature and volume emissivity in the upper atmosphere over the earth. It is one of the biggest technical challenges to develop a high-precision high-flux GBAII and then obtain the imaging interferogram of faint airglow using the GBAII. In this article, we developed two GBAIIs (GBAII-LCoS and GBAVTII) and studied and compared the luminous flux of the two GBAIIs. By deriving the luminous flux expression and executing calculations, we learned that the luminous flux of GBAII-LCoS for O2(0-1)867.7 nm, O(1S)557.7 nm, O(1D) 630.0 nm and OH(8-3)732.0 nm airglow is 107 photons s-1, while the luminous flux of GBAVTII for the same airglow is 109 photons s-1, showing a difference of two orders of magnitude. Both GBAII-LCoS and GBAVTII have a stronger capability to receive O2(0-1) than the other three types of airglows. Based on specific studies, we obtained the different incident angles corresponding to the maximum luminous flux of the same airglow. According to the comparison of outdoor experiment results relating to these two ground-based instruments, six interference rings are theoretically obtained by imaging 12 airglow spectral lines of O2(0-1) 867.7 nm, while five clear interference rings are obtained via the outdoor experiment of GBAVTII with the number of electrons around 1800-2200e. However, GBAII-LCoS only obtains three distinguishable rings with the number of electrons around 1100-1200e. The contrast ratio of interference rings obtained by the two instruments is 8:3, indicating that GBAVTII have a greater capability to collect nightglow. The study results in this article will provide a theoretical and experimental basis for further improving the luminous flux of ground-based imaging interferometers.
Based on the laser writing device developed by our group before, wiping the glow is necessary as a function added on the machine. This article is a theoretical and experimental study of glow wiping start from luminescence theory and infrared ray. The trap depths of ZnS: Cu and SrAl2O4:Eu2+, Dy3+ are figured out according to the TSL(thermos stimulated luminescent ) dynamics, then the accurate IR wavelength to release the trapped electrons in proper depth. We select every single wavelength of energy 1nm by 1nm from near IR and deliver it by crystal fiber. The glow fading curves of ZnS: Cu and SrAl2O4:Eu2+, Dy3+ are figured under IR. The TSL spectrum of ZnS: Cu and SrAl2O4:Eu2+, Dy3+are measured with a thermal luminescence meter. The experiment result of glow wiping has proved the theory. This paper provide a pioneer experiment and theoretical base for further study of IR quenching wavelength about more variety of LLP material.
A ground based airglow imager interferometer (GBAII) has made in our group to detect the upper atmospheric temperature and wind velocity at terrestrial altitude 90-100 km. GBAII’s sources are the airglow of O (1S) 557.7 nm at altitude of 97km and O2 (0-1) 867.7nm at altitude of 94 km. a uniform value of the atmospheric transmissivity was used in the forward and inversion process of GBAII, which was led to GBAII a lower wind measurement accuracy. The atmospheric transmissivity of O2 (0-1) airglow is calculated and simulated in this paper. Based on the analysis and calculation of the high level atmospheric absorption, scattering attenuation, scattering ratio, acquire transmittance and the attenuation ratio of CO2 and water vapor are obtained by adding the methods of weighted mean, number density of molecules, different height modified segments, the different correction factors vs. different atmospheric heights etc. By MATLAB programme, the atmosphere scattering ratio is obtained to be 1.876×10-3, CO2 transmittance to be 0 and water vapor to be 0.1888, respectively. The total atmospheric transmittance of O2 (0-1) airglow is 0.4663.
Image intensifier is the key components of low-light level night vision device. In order to extend its dynamic range of the night vision sight, a high voltage pulse gated power supply (HVPGPS) for image intensifier cathode is researched in this paper. The HVPGPS with pulse width adjustable is optimally designed for the image intensifier cathode power supply. Its pulse amplitude is 250 V, with 1 kHz frequency. Two different circuits are combined to get the adjustable pulse width from narrow to wide. The pulse width parameters are: the narrow pulse circuit is from 20 ns to 300 ns, and its wide pulse circuit is 300 ns – millisecond (ms). This HVPGPS can achieve the advantages of small size circuit, low power consumption, and which meets the requirements of image intensifier cathode power supply.
A prototype ground based airglow imaging interferometer (GBAII) has been constructed to observe the upper atmospheric wind velocity and temperature at an altitude of 90-100 km, but the GBAII’s wind speed accuracy was found to be unsatisfactory with a value of 21.0 m/s. Three theoretical aspects have been investigated to improve the accuracy, with the following finding: 1) By replacing the surface coatings of the GBAII’s 6 lenses and Michelson interferometer (MI) with a new wind-speed infrared film rather than the original visible light film, the accuracy can be increased by 3.0 m/s. 2) By replacing the original charge-coupled device (CCD) with a quantum efficiency (QE) of 0.38 at the wavelength of approximately 866 nm by an electron multiplying CCD (EMCCD) with QE of 0.95, the accuracy can be increased by 6.7 m/s. By adding all the factors that improve the accuracy of the GBAII, it can be improved by 15.0 m/s, which realizes the original aim of wind speed accuracy of 6.0 m/s. Experimental results have been obtained for two aspects: 1) By replacing the surface film on the GBAII’s 6 lenses and MI interface, the wind speed accuracy has been increased by 3.8 m/s. 2) A new GBAII temperature controller has been constructed to control the environmental temperature in 0.2 K steps. The results obtained by the GBAII on Dec. 6, 2013 show an average atmospheric temperature of 206.5 K, zonal wind speed of -26.8 m/s and meridional wind speed of 28.1 m/s. These results are close to those of the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite Doppler interferometer (TIDI) data collected at almost the same time.
The passive optical methods to observe the earthly upper atmospheric wind field by satellite remote sensing is to
measure the parameters including atmospheric wind velocities, temperature, pressure and volume emission rates of
airglow (aurora). WINDII is the first image interferometer for upper atmospheric wind measurement in 1991 made by
Canada and France loaded on NASA's UARS. The precision of wind speed is 10m/s for WINDII and its temperature
precision is 10K. The second wind measurement instrument of SWIFT is launched at 2011 based on the same principle
as WINDII. SWIFT's wind speed precision is 3m/s, and its temperature precision is 2K. According to the development of
the photoelectron technology and CCD, the wind field's detected precision is enhanced continuously. In this paper, the
theory of detected precision of wind speed and temperature is analyzed firstly; the factors between the higher precision
of wind field and CCD detector parameter are made sure. And then the precision equation is deduced. The wind speed
and temperature precision expression includes of optical path difference (OPD), phase, aurora wavelength, visibility,
CCD's responsibility, signal-to-noise, view of field (VOF) etc. The precision of 1m/s wind speed and 1K temperature
need fixed OPD 24.28cm with O+ 732.0nm aurora. This research can provide the theory for advance upper atmospheric
wind field detecting precision.
In order to improve the detectability of low-light imaging CCD (charge coupled devices), we have brought forward a
magnetic mirror device to apply to microchannel electron vase plate ((MEVP)) of low-light imaging system at room
temperature. After introduced the principle of restricted electron in magnetic mirror field to accumulate enough time for
low-light CCD imaging, magnetic intensity has been calculated discretionary position in the mirror, the formula of
electron's velocity direction has been given through the throat of magnetic mirror in this paper. The educed electron's
angle distribution between velocity direction and magnetic mirror axis has been simulated at 7-10 degree. This answers
for the design needs of microchannel vase plate now. The electron's loop speckle imaging has been obtained by
experiment; the result is same as theoretical value. It is proved that if the electrons educed by the magnetic mirror field at
the same cone angle and approximate speed, the gain of microchannel plate will be more stable, so that it is favorable to
reduce the noise of photoelectronic imaging.
The charge packet transfer rate is one of the most important factors of charge transfer losing (CTL) in Charge Coupled
Devices (CCD). It is important to build up a model of CCD structure parameters, charge transfer efficiency (CTE),
transfer frequency of charge packet and work temperature etc. But it is very hard to build up an exact theoretical model
and find the analytical solution neither math nor physics. The traditional discussion of the working principle of CCD
build up a nonlinear partial differential equation, but it just consider the remainder electrons concentration while integer
k=0. In this paper, we increase the result of the electrons concentration while k=1, 2,..., n, and discuss the result. A more
accreted result of the charge packet rate had been got. The result is 81 percent of the CTL which is traditionally
discussed about of CCD. Then the CTE in low temperature is discussed using the result. And the optimum frequency of
the CCD is corrected also. The correction of the charge packet rate in CCD can enhance the performance of CCD.
For remote sensing to measure upper atmospheric wind field by optical passive method on-load satellite, the emission
source is used of crepuscular aurora of OH 732.0nm. The time of exposure is need about 9sec by remodel Sagnac
interferometer, so there is a larger image motion on CCD and the measurement precision is limited. This paper has been
calculated the CCD image motion quantity based on remodel pushbroom model by Sagnac interferometer. The MTF
curve is demonstrated the image motion can be compensated. Then the techniques of TDICCD, the whole frame transfer,
swing mirror and photon memorizer to use compensate the image motion quantity.
KEYWORDS: Charge-coupled devices, Electrodes, Signal attenuation, Image enhancement, Molybdenum, Digital signal processing, Diffusion, Signal processing, Doping, Interfaces
A novelty circumambulating transferred area array CCD (Charge Coupled Device) working method is proposed, and its
work feasibility is proved. The new CCD can change the existing CCD complex structure, enhance the translational
velocity and transfer efficiency, reduce the design production cost and the dark current through the best electronic
transfer frequency. To solve the limitations of big noise which contemporary exists on glimmer imaging plan in IICCD
(Image Intensified Charge Coupled Devices) and EBCCD(Electron Bombarded Charge Coupled Devices), short life and
other shortage, the weak optical image detect-ability is enhanced through changed the CCD periphery ancillary facilities
and micro-channel electron vase plate is designed. It is proved through changing dispersivity of the photocathode
electron emission once time and divergence of the speed, improved secondary electron launch randomness of imagining
intensifier, then reduced the system the dynamic survey noise, enhanced IICCD and the EBCCD survey limitation.
Getting clear photographs of bubbles in water and extracting bubbles in the image of aerated water flows are the basis to
analyze the characteristics of water flows by image measurement. Because the bubbles in water are colorless, transparent
and deforming continuously, furthermore, they reflect and refract light at their boundaries. Up to now, almost all the
image processing of bubbles extraction in the images of aerated water flows have problems of miss-extraction or
deformity of bubbles which caused by un-uniformity of bubbles' boundary resulted from the un-balance illumination of
the image. In order to eliminate the noises in the background and identify the blurry boundaries, based on the systematic
analysis of the optical properties of bubbles in water, a set of formulas calculating the relationship between image gray
and bubble luminance are deduced in this paper which are applicable to different illumination settings and different CCD. A new method is developed to forecast CCD gray pattern based upon illumination variable and bubble shape, which was demonstrated by the experiments. The proposed method is expected to be used to design experimental scheme of image measurement, and can help to enhance the accuracy of image analysis.
The modified super-wide-angle Sagnac interferometer (SASI) is designed for upper atmospheric wind measurement. The
formula of SASI's optical path difference (OPD) is derived, in which the OPD versus the sine series of incidence angle
in order of 4. The SASI's fully compensations of super-wide-angle, achromatic, thermal, wavelength-independent
thermal conditions have been investigated. The SASI configuration for the above compensations was successfully setup
by selecting correct glasses from the 113 kinds of glasses. The optimized SASI is made of ZBaF17 and QF14 glasses,
and the arm lengths are accurately configured. Based on the configuration of glass types and arm lengths of SASI, it
shows that SASI achromatic condition is satisfied synchronously for three aurora's emission lines, which are 557.7nm,
630.0nm and 732.0nm respectively. The relative error of SASI's lengths does not exceed 1%. The full field of view
(FOV) of the SASI is 6°. It is about 5° in full angle from SASI optical axis to CCD farthest corner. The first order fringe
occupies about 67% of the CCD area.
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