The Bundle Adjustment in photogrammetry software is the program that processes the photographic measurements to produce the final XYZ coordinates of all the measured points. In order to do this, it must Triangulate the target points, Resect the pictures and Self-calibrate the photogrammetric equipment camera. The Bundle Adjustment program in photogrammetry software is called STAR, which stands for Self-Calibration, Triangulation and Resection.
The real power of the bundle adjustment in photogrammetry software is that it is able to do all three of these things simultaneously. If you review the descriptions of Triangulation and Resection, it appears there is a problem. In order to triangulate the measured points, we must know the orientation of the pictures.
However, in order to orient the pictures taken by photogrammetric equipment, we must know the coordinates of the measured points. How do we get started here? The answer is the bundle adjustment has the capability to figure them both out simultaneously and to self-calibrate the camera as well! This is where the name bundle adjustment in photogrammetry software comes from because it bundles all these things together and solves them all at the same time.
The Bundle Adjustment in photogrammetry software does need a little help though. It must have the preliminary orientation for each photograph in order to get started. This preliminary orientation is accomplished with the AutoStart or SuperStart procedures that are done for every photograph.
When STAR is finished it then produces the following:
1. XYZ coordinates (and accuracy estimates) for each point
2. The XYZ coordinates and 3 aiming angles (and accuracy estimates) for each picture.
3. The camera calibration parameters of photogrammetric equipment (and their accuracy estimates).