Abstract:The status and role of an infrared source in gas concentration detection are studied. The structural principles of three different kinds of infrared sources are presented. Their advantages and disadvantages are compared with each other and their applications are overviewed. Then, the performance requirements of infrared sources for gas detection are analyzed in detail. The notes for source selection are given. Finally, the development trend of infrared sources are elucidated according to the development demands for harmful gas detection.

Abstract:To solve the test problem of the data acquisition system of an infrared detector, a simulator which can simulate the output signals from an infrared detector is developed on the basis of the operating characteristics inherent in an infrared detector. The simulator not only can simulate the infrared detectors in different formats and output accurate quantitative image data, but also can provide frame, line, pixel and correlated double sampling synchronization trigger signals for the data acquisition system. The qualitative examination and quantitative calibration of the data acquisition system of the infrared detector are implemented by using the quantitative image data from the simulator. The results are of referential value to the effective and accurate measurement of the data acquisition systems of infrared detectors.

Abstract:The temperature of solid state propellant combustion flame is studied by a Bruker OPAG33 Fourier Transform Infrared Spectrometer (FTIR). The infrared emission spectra of Nitrate Ester Plasticized Polyether Propellant (NEPE) solid propellant are measured with a resolution of 4 cm-1 at a testing distance of 20 m in real time. The temperature of NEPE propellant plume is calculated by using the fine structure emission spectral lines of HC1 gas molecules released in combustion products. The experimental results show that a passive remote sensing FTIR can measure the temperature of solid propellant plume rapidly and non-contactly in real time. It is an effective means for research.

Abstract:The passive ranging principle of an infrared reconnaissance warning system is presented. The influence of bi-station distance and tri-station mode on ranging accuracy is discussed. An equilateral triangle disposal-optimal layout method for three joint station ranging is proposed. Its ranging accuracy for the target to be measured is analyzed. The simulation results show that the method can minimize the false alarm rate of target distance with the balance of the ranging accuracy in the range from 0 degree to 360 degree and the consistency. The site spacing of 1 km can ensure the location accuracy of the target to be better than 10% in the distance of 14.2 km. Thus, the three joint station ranging effectiveness can be improved greatly.

Abstract:As a core device in an infrared spectral gas analyzer based on Non-Dispersed Infrared (NDIR) principle, the pyroelectric infrared gas detector has its output signal characteristics closely related to the subsequent signal processing. On the basis of the synchronous tracking of excitation source and the output signals from a PYS3228TC_G1G20 pyroelectric infrared gas detector at different frequencies, the relationship between the excitation source and the output signals from the gas detector is analyzed deeply. Through these experiments, the initial signal characteristics of the pyroelectric infrared gas detector are summarized. The results provide an important theoretical reference for the signal processing of pyroelectric infrared gas analyzers.

Abstract:A target detection method for detection and location of mobile targets such as vehicles and airplanes on the ground based on a visual attention model is proposed. According to the factor that the mobile targets in natural scenes are small, a target saliency model for guiding target detection based on visual attention mechanism is designed. First, the features such as color, identity and orientation in a target image are extracted and are combined with each other to calculate the saliency map. Then, the saliency value is calculated in the unit of superpixel and a weight is provided for the difference among the superpixels at different distances by combining with the human visual sensitivity. The experimental results show that the algorithm can detect and locate mobile targets against complicated background on the ground effectively.

Abstract:According to the failure problem which might be occurred in the application of a sapceborne bus system, a test method for the physical layer and protocol layer of a 1553B bus is proposed. In the method, the test of the electric characteristics of the physical layer includes the analysis of voltage, waveform, code, etc. The test of the complex protocol layer includes the analysis of instruction transmission, address recognition, effective data, check bit and message interval, etc. Finally, the validity and practical applicability of this test method are verified experimentally.

Abstract:Since there are not test standards and equipment for the waveband transmittance of infrared fiber image bundle in China at present, both a thermal camera calibration method which takes fiber aperture angle and fiber diameter into account and a dual-band transmittance measurement method for a certain type fiber image bundle are proposed. To ensure the calibration condition and the aperture angle and diameter of optical fibers to be consistent, two apertures of 8 mm and 62 μm in diameter are set at both ends of a cold shield respectively. Then, the waveband to be calibrated is selected by inserting a band filter in the optical path. An infrared thermal camera calibration model based on least squares is established and is used in the calibration experiment. According to the calibration results, the transmittance values of a certain type optical fiber image bundle in the wavebands of 2.0-2.6 μm and 3.4-4.8 μm are measured. The average transmittance is greater than 70%.

Abstract:According to the demand for analysis and interpretation of infrared images in the fog, a new preprocessing method based on the dark channel prior to the principle of fog and HIS space is proposed. The method can enhance the contrast between the target and the background remarkably when it is used for the processing of infrared images in the fog. The experimental results show that this method can enhance and display infrared images in the fog effectively. Compared with the traditional image enhancement method, it is more conductive to the analysis and interpretation of infrared images of sea-skimming flight targets and the targets at sea in the fog.