Abstract:As the transition region from infrared light to microwave in the electromagnetic wave, the terahertz (THz) wave has its unique characteristics which are widely known. With the mature of the unit technologies such as THz radiation sources, detectors and so on, the THz technology has been firstly applied to space astronomical observation, deep space exploration and earth meteorological environment monitoring by USA, Europe and Japan. The development status of the THz technology for these applications is summarized mainly and the research status of THz radar technology and THz communication technology and their application prospects in the future are analyzed briefly.

Abstract:In recent years, with the rapid growth of China's economy, the more effective use of various resources has received more and more attention. In the practical industrial production, how to observe easier has always been the focus of attention. This demand means that the corresponding system should have strong real-time performance, good stability and high accuracy, etc. To solve the problems in the industrial production, a temperature measuring system which can scan and display results on line in real time is developed according to the infrared temperature measuring theory. The system includes software and hardware and also involves several theoretical difficulties in optical principles and temperature measuring point correction. The innovation points and difficulties of the system are how to use an infrared camera to collect the corresponding infrared temperature data accurately, how to integrate the data and send the data to a PC effectively, how to describe the dynamic observation of the graphics in the PC and how to increase the automatic tracking of high temperature points and other auxiliary functions.

Abstract:Currently, there are few products which can track high temperature targets in the market. Because most of the products in the market only have a temperature measuring function, it is not far enough to meet the different demands in various applications. An automatic tracking system which can track high temperature targets in real time is proposed. Its hardware system design, software design and algorithm principle are presented in detail. The experimental result shows that the system not only can implement the display of infrared images, but also can measure the temperature of the targets accurately and track them automatically in real time.

Abstract:A model for estimating the detection distance of an infrared imaging system with a focal plane array is established. Taking the influences of system observation environment conditions, infrared radiation characteristics of targets and infrared imaging systems with focal plane arrays on the detection distance into account, the model can estimate the detection distance of an imaging system for a specific flight target effectively. With this model, the key technical parameters of an infrared imaging system can be calculated and verified scientifically. Thus, the top design of a system can be strengthened, the theoretical foundation can be laid for the engineering practice and the development process of the relative imaging system can be instructed. Therefore, the model is of very important value to engineering applications.

Abstract:Atmospheric transmittance is an important factor affecting the operating distance of an infrared imaging system. In the process of atmospheric transmission, the infrared radiation may be affected by the selective absorption of atmospheric molecules, scattering and complicated weather conditions. This makes the atmospheric transmittance become a complex parameter. A spectral bisection method is used to calculate the atmospheric transmittance. Firstly, the MODTRAN software is used to calculate the atmospheric transmittance of each spectral line at a certain distance and establish a database. Then, the spectral region is divided at a certain interval and the atmospheric transmittance in each mini spectral region is calculated by calling the database. Finally, the calculated result is put into the model to calculate the operating distance of the infrared system. Compared with the calculation method which uses constant or average atmospheric transmittance, the calculation accuracy of the proposed method is improved. The effects of detecting height, humidity and fog on MRTD and operating distance of an infrared imaging system are calculated and analyzed.

Abstract:A near infrared spectrum preprocessing method based on Daubechies wavelet threshold is proposed. It is used to process the near infrared spectra of two kinds of apples. In the method, the normalized Correlation Coefficient (NC) and Peak Signal to Noise Ratio (PSNR) are selected as a quantitative analysis index. Compared with the Vector Normalization (VN) and Standard Normal Variate (SNV), the method has obvious advantages. It not only can effectively remove noises, but also can retain the details of spectral characteristics. So, the robustness of modeling and the accuracy of the established model can be improved in the subsequent spectral analysis.

Abstract:The detection and tracking of moving point targets in infrared images are studied mainly. Background suppression and enhancement are carried out for the infrared images with complex background. These processing are implemented by utilizing the advantages of átrous wavelet transform according to the feature that small targets are easy to be lose in infrared images. The possible targets are segmented by using a Fisher algorithm. Then, the small moving targets are tracked and extracted accurately by using an Eight Neighboring Region Analysis Algorithm (ENRAA). The experimental result shows that the proposed algorithm is of important practical value to the detection and tracking of moving targets in infrared image sequences.

Abstract:In combination with Plank's radiation law, a dual-band temperature measurement method is used to analyze the temperature and infrared radiation of a distant high-altitude target. A method for calculating the projected area of the target is proposed. Because the target is detected at a long distance, a model for calculating the atmospheric attenuation in arbitrary direction of two sides taking the curvature of the earth into account is presented. It is used to analyze the attenuation of infrared radiation in both 3 to 5 μm and 8 to 12 μm bands at different distances. The experimental result shows that in the high altitude about 10 km away, the measuring distance of the infrared radiation from the target can be increased from a few tens of kilometers in low altitude to hundreds of kilometers. This provides a theoretical and technical support for the further analysis of the radiation characteristics of targets.