Advanced Hyperspectral Imaging Sensors for UAVs

Hyperspectral imaging has emerged as a powerful and versatile means for continuous sampling of broad intervals of the spectrum. Previously, this was a difficult proposition because of the high speeds of air and space vehicle motion, resulting in insufficient time for a spectrometer to concentrate on a small area of the Earth's surface or an atmospheric target. A hyperspectral image consists of about a hundred or more spectral bands adjacent to each other and the characteristic spectrum of the target pixel is acquired in a hyperspectral image. The precise spectral information contained in a hyperspectral image enables better characterisation and superior identification of targets.

This technique has allowed hyperspectral sensors on board aircrafts, satellites to capture reflected radiation from ground target sensors and produce complete spectral signatures with no wavelength omissions. The reflected radiation from the object is captured by the spectral detecting system consisting of charge-coupled devices (CCDs), which can sample images at very small intervals and plot the data as quasi-continuous narrow bands that approximate a spectral signature rather than a histogramlike broader band. Sensors on board such moving platforms play a vital role in the nature of the image captured and its subsequent processing. Fitchburg, MA-based Headwall Photonics Inc. has been a developer of imaging sensors, which find application in many sectors. Augmented by years of dedicated research in the area of hyperspectral imaging sensors, Headwall has recently released Micro-Hyperspec VS.

David Bannon, Vice President, Sales and Marketing, Headwall Photonics, says, "Headwall has established a very extensive intellectual property position in the area of chemical sensing and hyperspectral imaging sensors. Our Hyperspec VS imaging sensors are the leading hyperspectral imaging solutions in use within the military/Department of Defense (DoD) and high-end research communities. The application deployment for Hyperspec VS sensors has ranged from target identification and tracking, to spectral tagging and surveillance, to battle-space awareness. To this end, our sensors have been deployed on piloted aircraft, unmanned aerial vehicles (UAVs) and satellite platforms."

Apart from having exceptional spectral and spatial resolution, the Micro-Hyperspec VS sensor has the ability to withstand harsh environments and is designed to meet the small-size, rigid design and weight considerations for UAV applications. With the ability to produce high-class images, due to the patented, all-reflective concentric imaging spectrometer, the sensing capabilities shown by this sensor are versatile. It also provides a high signal-to-noise ratio and removes imaging distortions, such as stray light, smile, keystone and so on, which pose a major challenge in spectral imaging applications. Based on application requirements, the sensor has been developed to operate in the visible and near infra-red range (350/400 nm to 1000 nm) or near infra-red range (900 nm to 1700 nm), facilitating a customised sensor solution.

Bannon told Sensor Technology, "It has been Headwall’s experience that it takes approximately 12 years to 15 years for technology to work its way out of a strictly DoD application environment to a commercial or industrial application set, and the market has reached that point where the technology has matured. For example, Headwall’s Hyperspec sensors are our sixth generation product, having been refined over time to provide exceptional spatial and spectral performance."

The most significant aspect of Headwall’s Hyperspec sensors is the commercial viability and deployment of hyperspectral imaging technology from what was once considered a DoD application. Not surprisingly, these sensors have been finding applications in civilian agencies (in some cases for the last twelve years) in a wide range of environmental remote sensing applications, such as the Ocean portable hyperspectral imager for low-light spectroscopy (PHILLS) sensor. Additionally, after extensive collaboration with key customers and based on market research, Headwall launched a new family of integrated hyperspectral sensors to address a number of key markets, such as product line scanning of moving Webs of product; process manufacturing sectors utilising multipoint/multiprobe analysis for quality control and process monitoring; noninvasive imaging/diagnosis utilising patient scans or fiber bundles; drug discovery and the civilian airborne sector.

"Headwall is very much interested in expanding collaboration into new markets and application areas. To this end, we are working with leading software integrators and establishing OEM [original equipment manufacturers] partnerships with organisations that have application-specific experience in markets requiring chemical sensing and imaging. For example, machine vision companies as well as medical imaging companies who are looking to obtain first-mover advantage in these high-growth areas. These collaboration efforts were initiated in 2005 during business planning for the launch of Headwall’s Hyperspec imaging sensors and continue to be a key element of our business strategy," Bannon added.

Headwall Photonics was formed in 2003 as the result of a management buy-out from Agilent Technologies.


David Bannon, Vice President, Sales & Marketing,

Headwall Photonics Inc.,

601 River Street,

Fitchburg, MA 01420.

Phone: 978-353-4003.

Fax: 978-342-3719.



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