Aerial images from the Follow-On Radar, Enhanced and Synthetic Vision Systems Integration Technology
Evaluation (FORESITE) flight tests with the NASA Langley Research Center's research Boeing 757 were
acquired during severe haze and haze/mixed clouds visibility conditions. These images were enhanced using
the Visual Servo (VS) process that makes use of the Multiscale Retinex. The images were then quantified with
visual quality metrics used internally within the VS. One of these metrics, the Visual Contrast Measure, has
been computed for hundreds of FORESITE images, and for major classes of imaging-terrestrial (consumer),
orbital Earth observations, orbital Mars surface imaging, NOAA aerial photographs, and underwater imaging.
The metric quantifies both the degree of visual impairment of the original, un-enhanced images as well as the
degree of visibility improvement achieved by the enhancement process. The large aggregate data exhibits trends
relating to degree of atmospheric visibility attenuation, and its impact on the limits of enhancement performance
for the various image classes. Overall results support the idea that in most cases that do not involve extreme
reduction in visibility, large gains in visual contrast are routinely achieved by VS processing. Additionally, for
very poor visibility imaging, lesser, but still substantial, gains in visual contrast are also routinely achieved. Further, the data suggest that these visual quality metrics can be used as external standalone metrics for
establishing performance parameters.