Research Of High Sensitivity Push-boom Infrared Camera Image Acquisition And Processing

With the quickly progress of infrared imaging technology, people have higher detection sensitivity requirements to infrared system. High sensitivity infrared imaging system has obvious advantages in small difference temperature detection, getting the temperature detail of target. It has profound significance for space exploration, target recognition, medical diagnosis, earthquake and climate forecast, etc.Push-boom is an important infrared camera imaging mode, it has been widely used in aerospace and satellite remote sensing. In contrast to the unit scanning and multi-element scanning, it can obtain a relatively long target dwell times, and increasing the exposure time of the target to improve system detection sensitivity.The project base on used the push-broom infrared camera application in the field of satellite remote sensing. In order to improve the detection sensitivity of the camera, an image data acquisition and processing system based on FPGA is designed, achieve by the K508 LWIR detector. The system use oversample-superposition combination with digital TDI to improve system detection sensitivity, particularly suitable for infrared detector with a small charge capacity and a short integration time.The research focuses in the paper is:1. AT first, the principle and meaning of infrared imaging is presented, both foreign and domestic development and application in this field are introduced.2. The noise in each part of the push-broom infrared imaging system is analyzed, and the corresponding noise cancellation technologies are introduced. Base on that, the paper giving the detailed computing and analysis for digital TDI and oversample-superposition influence to the system SNR, and proposed combination of these two methods to increase the push-broom infrared camera system sensitivity.3. Using K508 LWIR detector, an image acquisition and processing system based on FPGA is designed. The system can real-time implemented 4-channel image signal acquisition, background collection and elimination, image NUC, oversample-superposition, digital TDI, etc.4. Making the sensitivity test work for K508 imaging systems, the test result has little difference with the theoretical calculation, the system NETD can achieve better than 5mk, which has verified the scheme properly.