Method for calibrating the image from a mixel camera based solely on the acquired hyperspectral data

The mixel camera combines a new type of hardware component - an array of light mixing chambers - with a mathematical method that restores captured hyperspectral data with large keystone to its keystone-free form. When it is no longer necessary to correct keystone in hardware, the requirements to the optical design become much less stringent, and the mixel camera can therefore collect about four times more light than most traditional high-resolution cameras. However, for the mathematical data restoring method to function correctly, the geometry of the camera - such as the relative position of the image sensor and the slit - should be known with a small fraction of a pixel precision. Due to quite small sensor pixel size, it may be very challenging to make the camera so rigid mechanically that previously obtained calibration data remain valid for a long enough period. We will in this paper show how the captured hyperspectral data from the scene of interest, i.e., an unknown natural scene, can be used to give sufficiently precise calibration.