Analysis of * * line condition equation in photogrammetry

The conditional equation that the projection center image point and its corresponding ground point and three-point * * * line should meet. If the coordinates of the projection center S and an object point in a certain spatial coordinate system are XS, ys, ZS and x, y and z, respectively, and the image space coordinates of the corresponding image point are x, у and -f, then the * * * line condition equation is:

Where RT is the transpose matrix of rotation matrix r; λ is a scaling factor. The above formula can also be rewritten as: