Geometric Correction Of Airborne Optoelectronic Image Without Control Points

At present, the airborne electro-optical imaging technology plays an important role in various fields, especially in aviation reconnaissance. Airborne optoelectronic platform in the acquisition of images, due to its own attitude, height, speed and other factors resulting in geometric distortion of the image, reflects the position relationship between the objects in the real world mapping to image changes. Pixel itself and surface corresponding to the object of real space arrangement occurred bending, compression, migration and expansion.The distortion of the image is called the geometric distortion, and the correction to this distortion is the geometric correction.The existing methods of airborne optoelectronic platform image geometric correction mainly depend on the ground control points, and the use of polynomial fitting algorithm is used to correct the ground control points.Because of the large amount of airborne optoelectronic platform, such as a large amount of image, large angle and no regularity, this method needs a large number of ground control points and can obtain good image correction results.However, access to a large number of control points, the need for a dedicated measurement instrument and a large number of human and material resources. Especially in mountainous area, sea, forest and other areas, the terrain is complex and difficult to measure. It is difficult to measure the ground control points precisely.In this paper, the geometric correction of control points is introduced briefly, and then the geometric correction of the original distortion image of the airborne electro-optical platform is described in detail. To establish a precise geometric model, the Matlab Calibration Toolbox is used to obtain the camera parameters, and the inertial navigation system is used to extract the flight attitude angle and then obtain the camera external parameters.In this paper, the geometric distortion of airborne electro-optical platform is discussed, and the distortion is mainly influenced by the flight attitude and the rotating angle of the camera. The traditional method of geometric correction based on ground control points is introduced, and the limitation of the traditional method is analyzed.In this paper, the internal and external parameters of the camera and the coordinate transformation of the airborne electro-optical imaging system are studied in this paper. The principle and calibration model of camera calibration method are described in detail. Correct correction matrix is put forward. The solution of the internal and external parameters and distortion coefficients are given.The image acquisition process is carried out by using the airborne photoelectric platform load camera and image acquisition system. The camera parameters and distortion coefficients are extracted and optimized by the Matlab camera.In the laboratory is equipped with aerial photoelectric platform simulation process, the inertial navigation system and the camera are fixed to each other and on the PC display the extracted pose angle, combined with the rotation angle of the camera image coder read relative load completed the acquisition of the camera’s parameters.According to the intrinsic and extrinsic parameters of the camera, the transformation matrix of the distorted image to the corrected image is set up.Application of bilinear interpolation algorithm in Matlab programming, the geometric correction of the distorted image on PC is realized, and the correction rate is faster.In this paper, the root mean square error is analyzed, and the method is effective. The method can be applied to FPGA hardware for engineering application.