Topographical models of geographical areas may be used for many different applications. For example, topographical models may be used for flight simulators, urban planning, disaster preparedness and analysis, mapping, and military mission planning.
One common topographical model is the digital elevation map (DEM). A DEM is a sampled matrix representation of a geographical area that may be generated in an automated fashion by a computer. In a DEM, coordinate points are made to correspond with a height value.
There are two types of elevation models: a digital terrain model, and a digital surface model. A digital terrain model is also known as a bare earth model, which is a DEM that contains no manmade objects or vegetation. A digital surface model is also known as a reflective surface model, which is a DEM that contains manmade objects and vegetation.
Regions of interest (ROI) are specific objects within an area of interest (AOI) that are being modeled. Regions of interest are also known as regions, and include manmade objects and vegetation, such as buildings, aircraft, boats and different types of terrain.
User demand for three-dimensional (3D) models has grown steadily over the past several years. More recently, the need for “time critical” 3D models for situational awareness has become the more common need. Current model generation methods may not be cost effective and may require a considerable amount of processing time/resources, which makes these products impractical for some users.
Although users have become accustomed to lengthy turnaround times for 3D models, they tend to look for alternatives to shorten delivery time. Lengthy turnaround occurs for several reasons. For instance, searching for and acquiring two or more ideal images is time consuming, and the ideal images may not even exist. Registration of multiple images often takes a significant amount of time, which involves matching the points of a source image with all corresponding images. Manually drawing all the necessary regions takes time. Generation of multiple images is a long process since it involves more permutations per image. Moreover, there are instances where models need further editing for missing textures.
Accordingly, U.S. Pat. No. 6,229,546 discloses a geospatial image processing system wherein a terrain model may be rapidly generated with 3D object features. In particular, a secondary formatting process creates the generated world model as a series of instructions to populate the colored terrain skin, where appropriate, with 3D objects that simulate natural and man-made object features. However, depending on the application, simulated features may not be sufficient.
Change detection may be an important part of many geospatial image processing systems. Given the recent explosion of available imagery data and the increasing number of areas-of-interest throughout the world, the trend is towards rapid, automated change detection algorithms. U.S. Pat. No. 7,528,939 discloses an image change detecting system. The '939 patent is assigned to the current assignee of the present invention, and is hereby incorporated by reference. The image change detecting system includes an image processor cooperating with a geospatial scene model database for generating a reference geospatial image corresponding to the collected geospatial image, and a change detector cooperating with the image processor for detecting a change between the collected geospatial image and the reference geospatial image.
Notwithstanding the advances made in geospatial image processing systems, as well as in change detection associated therewith, there is still a need to improve the turnaround times for providing this information to a user.