The role of analytical internal orientation

The function of analyzing the internal orientation is to restore the internal orientation elements of the photo and partially eliminate the distortion of the photo. The process of determining or restoring orientation elements in an image is called internal orientation. The purpose of image orientation is to restore the beam shape during image shooting. In analog photogrammetry, the orientation in the photo is accomplished by setting the main distance of the instrument and the center of the photo. The so-called instrument main distance is to make the instrument main distance equal to the photo main distance by adjusting the distance between the instrument projection center and the image plane.