The geometric rectification of the digital aerial film image base on its comment information

There are comment information blocks on the edge of each aerial film, which recorded significant aerial imaging parameters. After the film digitization, we can get the value of imaging parameters by identifying and extracting the characters from comment information block automatically. The geometric rectification of the digital aerial film image based on these parameter values will eliminate the image geometric distortion caused by the change of flight attitude. This paper includes two parts, first introduces the character recognition process of comment information block, and then describes the principle of film image geometric rectification based on flight attitude angles.