COSMEC Subpixel Classifier

Powerful Image Exploitation
AAI's Subpixel Classifier software technology has been integrated with the US government's Common Spectral MASINT Exploitation Capability (COSMEC) software developed by the National Air & Space Intelligence Center (NASIC) located at Wright Patterson AFB in Dayton Ohio. COSMEC is a GOTS image processing package developed under the MASINT Spectral Processing & Exploitation Initiative (MSPEI). COSMEC software is an image processing framework designed to handle both multispectral and hyperspectral imagery and to be expandable through the use of software plugins. COSMEC Subpixel Classifier is one of the material classification techniques available as a COSMEC plugin.

Overview
COSMEC Subpixel Classifier is a state-of-the-art, supervised classifier that detects and reports whole and subpixel occurrences of a specific Material of Interest in multispectral or hyperspectral imagery. COSMEC Subpixel Classifier derives a signature for a specific material, groups all pixels in an image as either containing the material or not, and classifies all pixels that do contain the material into classes based on how much of the material they contain. It is a fully integrated, plugin to COSMEC.

Benefits
· Classify objects smaller than the spatial resolution of the sensor
· Discriminate specific materials in mixed pixels
· Detect materials that occupy from 100% to as little as 20% of a pixel
· Report the fraction of material present in each pixel classified
· Develop signatures portable from one scene to another
· Correct imagery for atmospheric effects
· Search broad-area images quickly to detect small or large features mixed with other materials

Features
· Powerful, low cost alternative to ground survey, field sampling, or high resolution imagery over wide areas or in remote locations
· Fully integrated with COSMEC
· Accepts airborne and satellite multispectral imagery such as Landsat Thematic Mapper, SPOT, IKONOS, and QuickBird multispectral imagery. Also works with hyperspectral imagery.

Unique Solution
COSMEC Subpixel Classifier is specifically designed to compensate for spectral mixing, atmospheric factors, and sun angle effects inherent to multispectral imagery. It applies an entirely different approach to background removal, environmental correction, and signature development. COSMEC Subpixel Classifier takes you beyond the bounds of traditional classifiers and succeeds where alternative subpixel techniques fall short.

By addressing the mixed pixel problem, COSMEC Subpixel Classifier can successfully detect a material even when it occupies only a fraction of an image pixel. As a bonus of the process, it tells you how much of the material is present in each pixel. You are aware not only of the material’s presence but also of the fraction of each image pixel it represents.

Because COSMEC Subpixel Classifier also addresses the spectral distortion of atmosphere and sun angle affects within an image, you can develop a material signature in one image and successfully apply it to others captured at different times and different places.

Technique
The COSMEC Subpixel Classifier processing technique is a new approach to deriving spectral signatures and applying them to imagery. Traditional classification techniques develop signatures by combining the spectra of training set pixels. These signatures encompass the contributions of all the materials in the training set. In contrast, COSMEC Subpixel Classifier’s Signature Derivation process extracts the component of the pixel spectra that is most common to the training set. The result is a signature that is representative of a specific material or set of materials.

Upon deriving a signature, conventional classifiers identify pixels in the scene that have the same spectral properties as the signature. COSMEC Subpixel Classifier, however, locates pixels containing the signature as a fractional component of the overall spectrum. COSMEC Subpixel Classifier performs a subpixel background estimation and removal process to produce a residual spectrum for each pixel in the scene. A detection occurs when the difference between the residual spectrum and the signature falls within a set of tolerances.

Suppression of subpixel background materials by COSMEC Subpixel Classifier allows classifications of materials even when they occur in mixed pixels containing a wide range of background materials. COSMEC Subpixel Classifier then reports the amount of the material associated with each pixel as both a histogram and graphic overlay.

When to Use
COSMEC Subpixel Classifier is designed as a complement to your existing suite of classification tools. It provides a higher level of discrimination for most applications. COSMEC Subpixel Classifier is highly specific because its background removal function attempts to remove dissimilar materials from pixels with the intent to provide a discriminating and unique signature of the material of interest. The resulting signature is specialized to your MOI. Traditional classifiers attempt to include all materials in the pixels.

Compatibility
COSMEC Subpixel Classifier working files are completely compatible with IMAGINE Subpixel Classifier files. This means that signatures developed in one process can be automatically used in the other. The processes used in both are based on the same code and are completely compatible. COSMEC Subpixel Classifier is currently available for Windows NT and Windows 2000 as well as Sun Solaris.

User Interface
COSMEC Subpixel Classifier comes with two user interfaces. The Subpixel Wizard interface is a wizard type interface that steps you through the processing sequence from start to finish allowing you to quickly produce a signature and apply it. The Subpixel Advanced user interface provides more control over the processes and is appropropriate for more advanced uses and refinement of the results.

Licensing
COSMEC Subpixel Classifier is a licensed plugin. Licenses are authorized by NASIC. The Windows version requires a hardware key which is available from NASIC. The Sun Solaris version requires a FLEXlm™ license file. Authorized users can obtain a FLEXlm™ license file from AAI.