
Editor in chief:Sheng-Li SUN
International standard number:ISSN 1672-8785
Unified domestic issue:CN 31-1304/TN
Domestic postal code:4-290
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zhaohangbin , Chai Mengyan , Sun Dexin , Liu Yinnian
2018, 39(6):1-7.
Abstract:To meet the demand of wide-swath and long-wave infrared hyperspectral imaging, a new design method of low-cost, light and miniature hyperspectral scanning imaging system for ground imaging is proposed on the basis of photoconductive HgCdTe linear detectors and plane blazed rasters. The system has 150 continuous spectral segments and a 30° imaging field angle in the 8~12.5 μm long-wave infrared range. It consists of a raster scanning mechanism and a field-of-view scanning mechanism, both of which are controlled synchronously to achieve fine light splitting and wide-swath imaging. The relations both between the angle of raster scanning and the detector received monochromatic wavelength and between the field-of-view scanning angle and the imaging field angle are deduced. On the basis of analyzing scanning positioning accuracy, a scanning system which uses a stepper motor as the core of motion and uses an operating mode of `whisk positioning+stop imaging'' is designed. The experimental result shows that the scanning system can meet the requirements of field of view positioning accuracy and light splitting accuracy. In addition, the silicon carbon emission spectrum curve obtained in the long wave infrared range shows that the design of the system is reasonable and effective. The design method of this scanning system is of guiding significance to the design of long-wave infrared hyperspectral systems.
WANG ZhaoLi , LIANG Jingtao , ZHAO Miguang , CHEN Houlei , WANG Juan
2018, 39(6):8-14.
Abstract:Since cryogenic optics can reduce thermal noise and improve the signal-to-noise ratio of detection systems, it is the necessary way to implement high sensitivity infrared detection. A cryogenic refractive optics which uses a pulse tube cryocooler as its cold source is proposed. This new cryogenic optics can be used in the occasions where volume and weight are limited and high-sensitivity infrared detection is required. The design process of the cryogenic optics is described in the aspects of optical design, opto-mechanical structure design and internal thermal noise analysis. A test system for verifying the feasibility of cooling optics by pulse tube cryocoolers is built and the effectiveness of the cryogenic optics is verified in the aspect of the thermal noise in the detection system. The experimental results show that the temperature of the optical components drops to 150 K from room temperature in three hours and can further drop to the lowest temperature 105 K. In the test process, the lens is well preserved, which verifies the feasibility of using a pulse tube cryocooler as the cold source. A blackbody and a 320× 256 pixel HgCdTe array detector are used to test the thermal noise of the optical system. The results indicate that the thermal radiation is decreased by 75% when the temperature of the optical system drops from 300 K to 215 K. This is in good agreement with the theoretical analysis result. It demonstrates the effectiveness of reducing noise for cryogenic optics.
lizhou , cailihua , zhangtao , lizhou
2018, 39(6):15-20.
Abstract:The ground-based infrared imaging system is one of the important imaging devices for target tracking and recording in real time. The ground-based long-wave infrared imaging system equipped with a high-performance infrared radiation calibration system can realize high-precision radiation characteristics measurement at room temperature. By establishing the model of a cooling infrared radiation characteristic measurement system, high-precision measurement of a target is implemented by a long-wave infrared radiation measurement system in the long-wave band from 7.7 μm to 9.3 μm. The experimental results show that the radiation measurement accuracy is 16.81 percent. It can meet the high-precision radiation measurement requirements of a shooting range.
2018, 39(6):21-26.
Abstract:A CO2 detection system based on a broadband light source and a Fabry-Pérot resonant cavity is presented. By combining with other active optical system error analysis methods, the error terms of the system are quantitatively analyzed. The main error source of the system includes four parts: the energy fluctuation of the light source, the crosstalk of the circulator, the change of the FP cavity spectral line and the noise of the detector. By modeling and calculating the influences of independent error items on the difference signal value, four main systematic errors are determined. In the error analysis of traditional atmospheric detection, the hardware system error is related directly to the concentration data. Instead, in the error analysis proposed, the hardware error and the inversion algorithm error are stripped. This method is of better guiding significance to the improvement of system operation ability.
zhangziru , DingLei , ZhangDongdong
2018, 39(6):27-33.
Abstract:A wireless optical transmission system is designed and built. According to the system receiver stability and signal-to-noise (SNR) requirements, the photodiode characteristics, circuit stability and bandwidth, receiver noise and signal-to-noise ratio of the receiver are deduced and analyzed in detail. The noise source in the receiver is analyzed in detail and the influencing factors and calculation methods are given. The quantitative calculation is performed according to the parameters of the experimental components. The photodiode preamplifier circuit is modeled and simulated on LTspice-IV. Its signal gain and noise characteristics are analyzed. The results are close to those of theoretical analysis. A 1 MHz square wave transmission experiment is made on the system. Good square wave signals can be obtained at the receiving end. This result shows that it can provide stable and reliable pre-stage signals for the subsequent signal processing module.
2018, 39(6):34-39.
Abstract:Volumetric 3D display technique is an important part of 3D display. Firstly, the volumetric 3D display techniques which are comparatively mature at home and abroad at present are classified. Then, the features of volumetric 3D display techniques are summed up. Although there are a certain limitations for the current technical schemes, the new technical schemes will appear in the future and gradually replace the existing 2D display.
LI Changyun , WANG Huilin , LIU Kang , ZHOU Xinhua
2018, 39(6):40-44.
Abstract:To realize the intelligence of spindle vibration detection technology, a vibration detection scheme based on mobile terminal operating system is proposed. The vibration measurement model of laser triangulation is improved. The linear relationship of vibration displacement change of the object to be measured to the displacement change of the reflected spot is deduced. A vibration measurement system which enhances data security and realizes long-distance transmission by WIFI is designed. The mobile terminal software is designed to reduce the volume of vibration measurement system, and the sliding average filter method is used to eliminate periodic interference. According to the uncertainty analysis, information entropy is used to express uncertainty. The actual test shows that the measurement uncertainty of the system is 2.66 bit. The research result is of a certain guiding significance to the design of vibration measurement scheme and lays the theoretical and experimental foundation for the later research on vibration measurement in mechanical related field.
2018, 39(6):45-48.
Abstract:Vertical planting has obvious functions in the improvement of urban environment. In recent years, vertical planting has been promoted vigorously in Shanghai. However, the investigation and planning of vertical planting faces the difficulty in the mastering of current status and potential resources. In Shanghai, the application of high resolution remote sensing images has solved the above problem effectively. The practical applications in Shanghai show that remote sensing has many advantages as well as some limitations. Through analysis, some relative ways are given for the limitations of remote sensing.
Editor in chief:Sheng-Li SUN
International standard number:ISSN 1672-8785
Unified domestic issue:CN 31-1304/TN
Domestic postal code:4-290