SPEEDING IMAGE SHARING
Written by CHERYL GERBER
SOLUTION ENABLES AIR FORCE TO DELIVER HIGH RESOLUTION GEOSPATIAL IMAGERY IN SECONDS.
For years, users who were sharing geospatial imagery would have to wait and whittle: Wait to download a huge geospatial image file, then whittle it down to the average 1 percent or 2 percent of the image they were after. The mammoth size of geospatial imagery strained communications architectures, while the lack of interoperability across storage and service networks made it difficult to manage imagery and data.
It was a slow, low-resolution process. Most client machines could not rapidly decompress gigabyte-sized geospatial information, and portable systems typically didn’t have the memory to handle it. Consequently, combatants could not always get the high-quality images they needed in time.
That scenario has faded, and is continuing to fade fast, owing to advances in open standards, compression and delivery technology and service-oriented architecture (SOA). Now, the situation is often quite the opposite. “We can give combatants at the most distant ends access to information quickly, in literally a matter of seconds,” said Kevin West, deputy chief, Surveillance Reconnaissance Infrastructure Division, Air Force/A2. “Our rough estimate is that 70 percent to 80 percent of the capability is being used by ground forces today.”
To deliver imagery and data to joint task forces and combatants in all of the services, the Air Force uses Image Access Solutions (IAS) software from ITT. IAS is based on JPEG2000, an image compression standard with improved performance over JPEG that was created by the Joint Photographic Exerts Group.
Using wavelet technology, JPEG2000 compresses large imagery with fine, alternating contrast, as the term “wavelet” suggests. It encodes an image from top to bottom sequentially, without having to buffer the entire image. JPEG2000 offers higher scalability and an editing feature for dynamic access, allowing users to choose which parts of an image to download to their client machine and which parts to leave on the server.
Using JPEG2000 and other technology, IAS can disseminate imagery in a matter of seconds at low bandwidths—even below 10 Kbps.
“Our challenge was to significantly shorten the time it took for critical users to obtain high resolution imagery. Our solution uses a non-proprietary architecture based on open standards for advanced compression and wavelet dissemination, allowing the Air Force to deliver imagery far more rapidly,” said Bruce Wald, vice president and director, Image Information Solutions, ITT Space Systems Division.
GEOSPATIAL STANDARDS
The JPEG2000 standard is approved by the National Geospatial Intelligence Agency (NGA) and is certified by the Joint Interoperability Test Command for the National Imagery Transmission Format (NITF), the Department of Defense standard for moving imagery. It is also an Open Geospatial Consortium-approved standard.
The streaming protocol technology in JPEG2000 that takes advantage of wavelet compression is called the JPEG2000 Interactive Protocol (JPIP). “The client sees a coarse image that becomes progressively more detailed, so the user can make a decision as it’s happening. You may decide the image is not what you want, and it is JPIP that allows you to stop it,” explained George Percivall, chief architect of the Open Geospatial Consortium (OGC).
ITT, a member of a technical OGC working group, began building IAS on a preliminary version of JPIP a few years ago. “For large imagery, people are realizing that JPIP is the way to go, so it’s now really playing into geospatial and remote sensing imagery. And it’s an open standard, so there are no patent issues,” said Kirk Benell, chief technical officer, ITT Visual Information Solutions, who is a member of an OGC technical working group.
Many organizations such as ITT have successfully used GEOTIFF (the geospatial version of TIFF), the Tag Image File Format developed by Aldus and Microsoft as a method of linking imagery with desktop applications.
But the technology advances of JPEG2000 and JPIP have outpaced GEOTIFF, exposing its limitations. “GEOTIFF doesn’t fit well into the geospatial Web metaphor. It’s not designed for interactive image transmission of specified data, so there are problems associated with large files over low bandwidth,” said Benell.
JPIP mimics some capabilities of Hyper Text Transfer Protocol (HTTP), which is used for moving documents around the Internet between clients and servers. It also utilizes the Universal Resource Locator (URL) concept for parameters that define specifically what information is required out of the target imagery.
WEB-LIKE PERFORMANCE
The familiar Web-like performance of JPEG2000 and JPIP translates into flexibility and ease for the user. “With JPEG2000 you compress the imagery version once; then you decompress many different ways depending on the parameters you provide, such as location, size, resolution, color bands and sharpness of image,” explained Benell.
JPIP not only takes advantage of wavelet technology, but also is tuned to preserve bandwidth. “JPIP has a caching mechanism that coordinates between the client and server. JPIP client technology sends the request to the server, which has JPEG2000. The server uses the requesting information to determine what it needs to send back to the client. And the JPIP client technology maps the image to just the requested information, which is why you get high throughput,” he said.
Founded on the JPEG2000 and JPIP standards, IAS software has an Internet look and feel and reflects a growing move toward the tools and underlying SOA that emulate Internet technology concepts. HTTP and XML (eXtensible Markup Language) are both used to facilitate SOA, as the architecture makes use of XML language to describe data and the HTTP request/response protocol between clients and servers for the transfer of information.
By using the concept of loose coupling, or minimal dependence, SOA allows users to access resources on a network in a way that is independent of the underlying platform and programming language. Since SOA is not tied to a particular technology, it can be deployed using a wide range of technologies as independent services with defined interfaces that perform their tasks in standard ways. The services are therefore interoperable, allowing enterprises to respond more efficiently, flexibly and cost-effectively to changing conditions.
“The evolution of service-oriented architecture and the technology associated with that has facilitated data level interoperability in a manner that wasn’t available to us before,” said West. “XML is one of those technologies that enables the sharing of data and allows the establishment of metadata catalogs to discover, access and retrieve the data over different systems.”
“A Website data page can provide all images available, regardless of sensor of origin, and tell you information about the image, such as where it came from. The access is over a secure server that is available to combatants at all levels,” said West. “You go to a Website where the IAS client is available and then use the IAS tools to discover the data, access and retrieve it.”
The IAS software combats previous problems of slowness, low resolution and lack of interoperability. “With IAS, we wanted to minimize the time cycle for the acquisition of data, processing, fusion and dissemination. And we wanted to exploit the sharing of information across nontraditional boundaries with coalition forces while still maintaining security and data integrity,” said Wald.
“It’s based on a simple mouse click. You just point and click on the part of the image you want to get,” added Rick L’Heureux, director of business development, ITT Image Information Solutions.
GUN COAST
BAE Systems is also utilizing Web technology in a surveillance and targeting system the company recently began developing. NGA selected BAE to build the system to identify battlefield targets and other possible threats rapidly, in order to speed decision making by intelligence analysts and military personnel. The BAE Gun Coast team consists of General Dynamics, Dragon Research and NGC.
NGA awarded BAE a $47 million contract to deliver the Global Net-Centric Surveillance and Targeting (GNCST) system with a Web-based interface on a secured network. The “Gun Coast” system, as it’s called, will gather real-time data from multiple intelligence sensors and process it into usable information for military and intelligence communities.
The goal of GNCST is to reduce the time and resources required to collect, process and fuse vital pieces of information, collected from many different sources and sensors. “Once GNCST is operational, an end user might ask the system to locate surfaceto- air missiles that appeared in a specific region within the past 45 seconds,” said Scott Boyce, BAE Systems’ GNCST program manager in San Diego. “In as little as a few seconds, Gun Coast would respond with target coordinates for those missiles.”
BAE’s Geospatial eXploitation Products (GXP) import a number of standard file formats, including GEOTIFF, JPEG2000 and all NITF versions.
ITT and BAE Systems’ adoption of standards such as JPEG2000, JPIP and others reflect the growing move toward SOA and facilitating technologies such as XML and Geography Markup Language (GML). According to ITT’s Benell, “XML is the alphabet, and GML is a language that uses that alphabet.”
“As more systems have embraced standards, interoperability has started to happen,” noted Joe Hassinger, senior engineer, BAE Systems Integrated Product Team, National Security Solutions, San Diego. “JPEG2000 and JPIP are exciting open standards that can enable the enterprise to get the right data at the right time to the right user. The client can tailor the data delivery based on bandwidth constraints using the JPIP standard and the underlying JPEG2000 technology.”
In February, NGA issued a document, entitled “Enabling a Common Vision,” that outlines the baseline standards for the National System for Geospatial Intelligence (NSG). The NSG endorsed a set of specifications known as the OGC Spatial Data Infrastructure, which includes OGC standards such as GML and other SOA facilitators.
“We are trying to move toward commercial standards in presenting imagery as well as geospatial data, and metadata encoded in GML is absolutely critical,” said Steve Wallach, NGA technical executive.
Also in February, the Department of Justice issued the Global Justice Reference Architecture, which the agency described as a resource for SOA and XML.
Air Force/A2 is pushing forward with standards for sharing geospatial imagery and data by incorporating ITT’s IAS software in its version of the Distributed Common Ground System (DCGS), a DoD-wide program with various implementations by the different services. To ensure interoperability across those implementations, all the services have agreed to use the DCGS Integrated Backbone (DIB).
“DCGS is moving away from stovepipes toward a common ground system that allows us to share data seamlessly. By tying A2/ IAS to the DIB and making it DIB-enabled, it makes IAS available to all the services and improves our ability to disseminate multiintelligence data,” West said. ♦