Pushbroom sensors sample only a narrow strip underneath the flight platform in the cross-track direction, and a full ground image cube is built by combining several subsequent strips during flight. Unfortunately, a critical problem arises when the flight platform undergoes sudden attitude changes due to wind gusts and turbulence. In such cases, the individual pushbroom image strips are no longer parallel to each other; they may oversample the scene on one side of the platform and under sample the scene on the other side, or exhibit other geometrical distortions. The end result is frequently severely distorted imagery that has a reduced utility. To this end, OKSI can provide a motion compensation software tool which corrects distortions within raw pushbroom HSI imagery and also performs orthorectification and georegistration. Overall, the tool provides the following:
- Performs motion compensation to remove distortions due to wind gusts and turbulence
- Orthorectifies the hyperspectral imagery
- Georegisters the hyperspectral imagery
A flight version of OKSI’s HyperScan sensors provides all the required sensor hardware and data capture for full motion compensation.
Georegistering hyperspectral imagery aligns the image in the scene with a geodetically (latitude, longitude, elevation) calibrated Earth based coordinate system. It transforms the position and size of pixels taken in the frame of sensor platform to the ground based reference system of the scene, and restructures them so that the pixels form a rectangular grid. Georegistering hyperspectral imagery also allows it to be fused with other georegistered sensor data, which may then allow correlation of the information between different modalities, and the creation of multi-layer geographical information systems (GIS).