The problem of robust automatic road detection in remotely sensed images is complicated by the fact that the sensor, spatial resolution, acquisition conditions, road width, road orientation and road material composition can all vary. A novel technique for detecting road pixels in multi-source remotely sensed images based on the phase (i.e., orientation or directional) information in edge pixels is described. A very dense map of edges extracted from the image is separated into channels, each containing edge pixels whose phases lie within a different range of orientations. The edge map associated with each channel is de-cluttered. A map of road pixels is formed by re-combining the de-cluttered channels into a composite edge image which is itself then separately de-cluttered. Road detection results are provided for DigitalGlobe and TerraServerUSA images. Road representations suitable for various applications are then discussed.

The Image Content Engine (ICE) is being developed to provide cueing assistance to human image analysts faced with increasingly large and intractable amounts of image data. The ICE architecture includes user configurable feature extraction pipelines which produce intermediate feature vector and match surface files which can then be accessed by interactive relational queries. Application of the feature extraction algorithms to large collections of images may be extremely time consuming and is launched as a batch job on a Linux cluster. The query interface accesses only the intermediate files and returns candidate hits nearly instantaneously. Queries may be posed for individual objects or collections. The query interface prompts the user for feedback, and applies relevance feedback algorithms to revise the feature vector weighting and focus on relevant search results. Examples of feature extraction and both model-based and search-by-example queries are presented.

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Ground-reference techniques for the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7 are described. The techniques are similar to those used for many years for Landsat-5 Thematic Mapper (TM). Recent results with the Landsat-5 TM are presented, including comparisons with hyperspectral, airborne imaging data. These results show that the Landsat sensor has remained stable within the 5% uncertainty ofthe ground-reference methods for the last five years. The airborne imagery is also used to show uncertainties due to registration errors, spectral differences, and spatial resolution differences in cross-comparison techniques planned for Earth Observing System sensors. In addition to the use ofthe traditional methods and test sites, a smaller test site local to the University ofArizona area is being evaluated for use with ETM+. This site, while not as bright, spatially-uniform and large as typical sites, allows more frequent calibrations and hopefully a better understanding ofthe calibration as a function of time. The selection of the test site, its properties, and example results of calibration of Landsat-5 TM are presented. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/22/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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