Abstract:Since the infrared payloads for Unmanned Aerial Vehicles (UAV) can operate under the bad weather conditions of cloud, rain, fog and haze day and night, they are widely used in disaster information acquisition and emergency mapping support. Many applications and practices of UAV infrared payloads in several relative fields are described. Their application status in emergency mapping support aspects such as monitoring and assessment of geological disasters, early warning and rescue of forest fires, monitoring of meteorological and hydrological disasters, emergency investigation of environment issues and search and rescue in bad environment is summarized. The existing technical issues and difficulties and their corresponding solutions are discussed. Finally, some suggestions are given for the development of UAV infrared payloads in automatic disaster recognition and detection.

Abstract:When a laser pulse propagates through a cloud, the phenomena such as energy decay, angle diffusion, temporal broadening and spatial dispersion may occur for it. The Monte Carlo method is used to study the effect of cloud altitude and thickness on laser downward transmission. The energy, angular, temporal and spatial distribution values of a laser pulse after it transmits downward to the sea level through a cloud are simulated respectively in both a situation that the cloud thickness is fixed while the cloud altitude is changing and a situation that the cloud altitude is fixed while the cloud thickness is changing. The result shows that when the cloud thickness is fixed, the Full Width Half Maximum (FWHM) and spot size of the laser pulse at sea level increase obviously with the increase of the cloud altitude. However, its energy and angular distribution values remain unchanged. When the cloud thickness is increasing while the cloud altitude is fixed, the energy of the laser pulse at sea level decreases, its angular distribution firstly diffuses and then trends to be stable, its FWHM increases and its spot size firstly increases and then trends to be stable. This research is of a referential value to the performance evaluation of optical communication systems.

Abstract:Temperature detection is very important in scientific research and social life. With the increasing development of science and technology, the demand for temperature detection is increased quickly. To solve the problem that temperature detection can not be carried out directly or only can be carried out in cable form in some special circumstances such as sealing, high temperature, high pressure and dust in biological and chemical experiments, a temperature acquisition system based on infrared communication is designed. In the system, a DS18B20 sensor is used as the temperature sensor and a 51 single chip microcomputer is used to collect temperature signals. The collected temperature signals are output through a serial port and are used to modulate the 38 kHz carrier so as to form infrared signals. The infrared signals are received by an integrated infrared receiving head VS1838B in the receiver. Finally, the temperature information is displayed by a LCD1602 device. The experimental result shows that the system can implement the non-contact detection of environment temperature and meet the experimental requirement.

Abstract:A high efficient tunable mid-infrared Optical Parametric Oscillator (OPO) based on a periodically poled MgO-doped lithium niobate (PPMgLN) crystal is reported. By using a self-designed Laser Diode (LD) double-end-pumped optoacoustic Q-switched Nd:YVO4 laser as the pumping source of the OPO, the quasi-phase matched single resonant mid-infrared laser output is achieved. When the pumping source has its power of 14.37 W, the idler light output with an average power of 2.39 W is obtained. Its conversion efficiency is 16.63%. By adjusting the period of the PPMgLN crystal, the wavelength of the idler light can be tuned in the range from 3.41 μm to 3.97 μm.

Abstract:The image rotation generated in the multi-parallel scanning process of a 45 degree rotary scanning mirror of a spaceborne infrared scanning imager is analyzed. A model for image correction is constructed. The generation mechanism of image rotation and image correction methods are described. Through the simulation analysis of remote sensing images, the validity and feasibility of the scheme to use a ground software to eliminate image rotation are verified preliminarily.

Abstract:Since the effectiveness of infrared imaging guidance simulation is determined by the validity and fidelity of typical effect modeling and simulation of an infrared imaging sensor system, it is very significant to study the evaluation method of typical effect simulation of an infrared imaging sensor system. A method for evaluating the simulation image of an infrared imaging sensor based on Structural Similarity (SSIM) and fidelity is proposed due to the shortage of evaluation method of simulation of infrared imaging sensor systems at present. In the method, the SSIM is used to evaluate the brightness, contrast and structural similarity of the simulated image while the fidelity is used to evaluate the spatial geometric characteristics and gray level distribution of the simulated image. The experimental result shows that the proposed method can evaluate the degradation effects such as blurring and noise of the infrared imaging sensor system effectively. It is suitable to verify and evaluate the quality of modeling and simulated images of infrared sensors.

Abstract:Since infrared detection and guidance technologies are more widely used in the modern war, how to generate the infrared images of battlefield environment in real time becomes very important. A visible flying scene is constructed by using Visual C 6.0 and OpenGL. The infrared radiation characteristics of the target and background models in the scene are analyzed mainly on the basis of the theory about infrared radiation. The infrared radiation intensity of each part of the models is calculated. At the same time, the effect of atmospheric attenuation is analyzed by using LOWTRAN7 and a real-time dynamic infrared flying scene simulation system is constructed through grey level quantization and OpenGL's rendering. The experimental result shows that the system can generate the infrared images of flying targets in different infrared wavebands in different atmospheric environment.

Abstract:Selecting the characteristic wavelength in spectra for modeling can reduce the interference by redundant wavelengths and improve modeling accuracy. The spectral data of 104 soil samples collected are preprocessed by a wavelet threshold de-noising method. The wavelengths are selected for modeling by 9 wavelength selection methods including interval partial least squares, uninformative variable elimination, successive projection algorithm and swarm intelligence algorithm. The results show that the wavelet threshold de-noising method can reduce the noise in spectra effectively. Using wavelength selection methods to select the wavelengths for modeling not only can reduce modeling variables, but also can improve the prediction accuracy of the model. Particularly, since the discrete particle swarm optimization algorithm uses 26 wavelengths for modeling, its prediction determination coefficient reaches 0.81 and its relative standard prediction error is 2.31. The selection of spectral wavelengths not only can reduce the complexity of the model, but also can effectively predict the organic matter content in soil.