Multispectral Imaging

Multispectral Imaging refers to the capturing of images at specific wavelengths of light to create data products.  A normal color camera, for example, is considered a multispectral imager and the red/green/blue (RGB) filters are selected to create good color photos.   For many applications, however, the typical RGB spectral bands for color imaging are not the most effective.  For low spectral contrast targets, such as military targets that are being camouflaged, very specific spectral bands can be used to differentiate between the target and the camouflage. ACT uses multiple spectral cameras to collect data, fuse the imagery, and with a variety of image processing techniques, enhance certain objects in the scene that have specific spectral properties.
Maritime & Land Based Applications
  • Marine Mammal Detection
  • Countermine
  • Search and Rescue
  • Anti-Submarine Warfare (ASW)
  • Counter Canopy
  • Normalized Difference Vegetation Index (NDVI)
  • Camouflage
  • Anomalies
Data Examples

Submerged Target Detection
Marine Mammal Detection
Countermine Detection
Marine Mammal Detection

Hyperspectral Imaging


Hyperspectral Imaging is similar to Multispectral Imaging except that the number of discrete wavelengths monitored is typically much higher. Multispectral imagers typically use 2-6 bands, but a hyperspectral sensor will use many more, often up to 150 spectrally continuous bands.  ACT currently offers several gimbals with a shortwave infrared (SWIR) hyperspectral line scan imager.  The turrets contain a Headwall Spectrometer with a FLIR SWIR imager that will interrogate a line underneath the aircraft. Each of the ~350 pixels on that line is resolved into 150 spectral bands.    As the plane flies forward, each line is used to build up a 2-dimensional image, with 150 bands of spectral data obtained for each pixel. To keep the data rates high, ACT subsamples the data and uses ~32 bands to perform spectral analysis to identify its chemical properties at each point.  As the image gets developed with sequential line scans, we can perform image analysis to look for targets of interest.  The current systems detect from ~900nm to 1600nm, with other wavelength ranges being investigated to move into the visible and extending out into the mid-IR range.

Maritime & Land Based Applications

  • Oil Spill Analysis
  • Chemical Analysis
  • Vegetation Analysis
Data Examples

Visible Bands
SWIR Bands
Ground Truth (Chemical Detection)

Wide Area Mapping

ACT's newest gimbal is for conducting Wide Area Mapping. The ACT Mapping system includes the gimbal with a 29MP color camera and a software suite to plan the flight path, collect, and review images in real time. The system allows for single pass collection of wide areas by providing a lateral step-stare capability to dramatically increase swath width. The planning software enables autonomous image collection so that the camera is triggered only when required, providing the proper overlap in all directions to facilitate mosaic creation. For ease of viewing during flight and after landing, the software provides a tiling function so that only the data you want to see are downloaded. As with all of the ACT 500 Series gimbals, the Cloud Cap TASE400© is used, allowing for ViewPoint operation if required.

Data Examples

Mission Planning
Data Review
Image Projection
Mosaic onto Map