This paper presents the innovative SatTel framework, designed to automatically access, collate, process, and exploit commercial satellite imagery from a wide variety of vendors. Established vendors such as DigitalGlobe provide high resolution imagery with limited coverage, while disruptive vendors such as Planet and BlackSky provide low resolution imagery with near global coverage. SatTel provides a single point of entry for exploitation of these contrasting and complementary vendor capabilities. The authors illustrate the value of the SatTel framework via demonstrative change detection capabilities. SatTel change detection from small satellite imagery based on comparison of image to image appearance achieves mean average precision (MAP) above 0.75 for many sites compared to ground truth analyst annotation. SatTel change detection from high resolution satellite imagery based on multidimensional geometric structures achieves an average precision of 0.84 for elevation changes above 3.0 meters compared to ground truth analyst annotation.

This paper examines the problem of detecting changes in a 3-d scene from a sequence of images, taken by cameras with arbitrary but known pose. No prior knowledge of the state of normal appearance and geometry of object surfaces is assumed, and abnormal changes can occur in any image of the sequence. To the authors' knowledge, this paper is the first to address the change detection problem in such a general framework. Existing change detection algorithms that exploit multiple image viewpoints typically can detect only motion changes or assume a planar world geometry which cannot cope effectively with appearance changes due to occlusion and un-modeled 3-d scene geometry (ego-motion parallax). The approach presented here can manage the complications of unknown and sometimes changing world surfaces by maintaining a 3-d voxel-based model, where probability distributions for surface occupancy and image appearance are stored in each voxel. The probability distributions at each voxel are continuously updated as new images are received. The key question of convergence of this joint estimation problem is answered by a formal proof based on realistic assumptions about the nature of real world scenes. A series of experiments are presented that evaluate change detection accuracy under laboratory-controlled conditions as well as aerial reconnaissance scenarios.-