In-scene multi-angle surface-specific signature generation and exploitation

Abstract

An angularly-dependent reflectance of a surface of an object is measured. Images are collected by a sensor at different sensor geometries and different light-source geometries. A point cloud is generated. The point cloud includes a location of a point, spectral band intensity values for the point, an azimuth and an elevation of the sensor, and an azimuth and an elevation of a light source. Raw pixel intensities of the object and surroundings of the object are converted to a surface reflectance of the object using specular array calibration (SPARC) targets. A three-dimensional (3D) location of each point in the point cloud is projected back to each image using metadata from the plurality of images, and spectral band values are assigned to each value in the point cloud, thereby resulting in a multi-angle spectral reflectance data set. A multi-angle surface-specific signature (MASS) is fitted to the multi-angle spectral reflectance data set, and the multi-angle surface-specific signature of the object and the surroundings of the object are stored into a spectral database. The spectral database is mined to find one or more of spatial and temporal anomalies in the plurality of images and patterns and correlations of the multi-angle surface-specific signature.