Research On Infrared Image Real-time Nonuniformity Correction Technology

Infrared imaging technology is widely used in many departments. Above all it is used in military field. Imaging system of infrared focal plane arrays (IRFPA) is future development direction of infrared system (IRIS). It is very important to develop little mobile and high clearance imaging of IRFPA.IRFPA is widely used in IRIS, but the non-uniformity from IRFPA greatly limits the infrared image quality. In order to improve quality of infrared image the non-uniformity must be corrected. But the correction of non-uniformity costs a lot of time to process the data that it is important to realize the correction at real time.This paper firstly introduces the non-uniformity of the infrared focal plane and analyzes the causes of the non-uniformity. And we summarize several main correction algorithms and the principles. On the basis of the comparison of these correction algorithms, we improve some algorithms on problems of deviation and non linear response. To meet the requirement, this paper introduces an infrared imaging process system based on DSP. The main design idea and the specific design of the system are presented, such as the hardware design and the software design. EDMA transmission technology and pipelining are applied in the design of the system. The experiment result indicates that the application of EDMA transmission technology and pipelining greatly improves system's working speed and satisfies the requirement of non-uniformity correction at real time.We improve infrared imaging system's performance at two aspects, which are data transmission and correction algorithm.1. Bring forward the method of data transmission with EDMA. This method not only improves the transmission speed of imaging data and correction data but also realizes the parallel operation of data transfer and data processing as a result of EDMA's capacity of background data processing independent of CPU.2. In order to improve the correction precision, we add deviation correction part to the whole correction. The piecewise linear interpolation algorithm is applied to revise the nonlinearity of the response curve. The application of technologies of parallel processing and software pipelining improves the real-time correction speed and satisfies the requirement of quality and speed of real-time non-uniformity correction of infrared imaging system.