Based On 45 ¡ã Rotation Scan Mirror Image Distortion Correction

Since 45°rotation scanning mirror is the most mature and common photo-mechanical scanning mode, having the wide range of applications in the satellite remote sensor. But 45°rotation scanning mirror in the scanning process will have a rotation, using the scanning method directly will not register in the multi-pixel parallel scanning system.There are many methods to resolve the image rotation, these methods can be divided into hardware and software methods. Hardware methods such as dove prism, K prism system. These methods all can eliminate the image rotation caused by 45°rotation scanning mirror. But, Due to the restriction of optical material, dove prism could only be used for visible to near-infrared bands. And K prism system have some questions that optical lengthening, increased volume and difficult to register while instantaneous field of view is smaller. Compared with eliminating the image rotation used by software, this method is more reliable and easier to achieve. Therefore, the method has been paid more and more attention.The main jobs of this thesis include:1. Since 45°rotation scanning mirror real-time correction need correct the geometric distortion of the image. So this thesis analyses the reasons and correction methods of image geometric distortion at first.2. Based on the vector theory of optical reflection, the thesis has studied imaging characteristics and the reason of resulting in imaging rotation of 45°rotation scanning mirror. The thesis has given the corresponding formulas of the scanning trace of 45°multi-parallel scanning mirror. According to the relationship between the pixel coordinate and the coordinate of ground and resample, we can eliminate the image rotation.3. Furthermore, this thesis has studied the scanning trace and the biggest awing angle in the two-scan mode of 45°rotation scanning mirror. The thesis also has studied on realization of eliminating image rotation and corrected the distorted image to achieve the real-time correction technology in the two-scan mode.On the basis of various experiments and analyses, images after calibration are detailed and have clear edge. Contrast the similarity of the original image and the image after distortion correct the effect of software is better and thus it proves the method can eliminate image rotation of 45°rotation scanning mirror effectively.