ObliqueMapper: How it Works
Overview
At the core of ObliqueMapper™ lies a rigorous set of equations based upon the principles of modern analytical photogrammetry. The application of mathematical conditions such as coplanarity and collinearity and the use of bundle block adjustments and least squares minimization ensures that you obtain the best quality data possible from your photographs.
Camera Orientation
In photogrammetric terms, every photograph has an internal and external orientation. The internal orientation establishes the relationship between the individual pixels of the image and the location of the camera (often called the camera station). The external orientation states the exact position (x, y, z) and angles (omega, phi, kappa) of the camera in reference to a particular coordinate system (e.g. UTM).
Internal orientation requires detailed information about the camera including the focal length, sensor size, and lens distortion parameters. Focal length and sensor size are often available in the specification section of the camera's manual. Lens distortion parameters (e.g. barrell distortion near edges of the photo) are typically not known, but can be determined through a calibration process within ObliqueMapper™.
External orientation is determined from additional information provided by the user. Within ObliqueMapper™, there are two stages to determining the external orientation of each photograph in the project: relative orientation and absolute orientation.
