Mosaic Maps: 2D Information from Perspective Data

The US military has a need to find detailed maps of a specific region that is current to within a few hours. The current technology for this involves Unmanned Aerial Vehicles (UAV), which are portable, are easy to maneuver, and can provide images at standard video refresh rates. The mosaic software from the Aviation and Missile Research, Development, and Engineering Center (AMRDEC) stitches images viewed from above by the UAV camera (30 field-of-view) providing a composite map of an area of interest as shown in Figure 1. In general, mosaicking is the process of combining multiple images to form a single image, or image mosaic. The image mosaic process involves geometrically aligning single images to create a composite image of a larger area. AMRDEC’s mosaic software provides an almost real-time, composite map of all the images seen by the UAV camera. This non-georeferenced map can be georeferenced using a satellite map of the area and either manually or automatically matching geometric features. The end result is that the UAV operator has a current, geo-referenced map, of all the area seen by the UAV camera. The operator can then zoom in on areas of interest contained on the mosaic map. However, most UAVs in the field have a single camera whose focus lies along the ray 30 from the fore-aft plane of the UAV. This perspective is ideal for flying the aircraft, and AMRDEC would like to modify its mosaicking algorithm to use these perspective images in place of top-down images (i.e. 90 from the fore-aft plane of the UAV). Many small UAVs currently fielded by the military are equipped with a forward-looking camera. Adding a down-looking camera to fielded UAVs would be an easy solution that would facilitate AMRDEC’s current mosaic software capabilities. However, to retrofit all the fielded systems would be very expensive. AMRDEC’s mosaic software uses a Real Time Mosaic Processor purchased from Sarnoff Acadia to generate a Mosaic. The Acadia processor forms a mosaic image by: