A novel multispectral video system that continuously optimizes both its spectral range channels and the
exposure time of each channel autonomously, under dynamic scenes, varying from short range-clear
scene to long range-poor visibility, is currently being developed. Transparency and contrast of high
scattering medium of channels with spectral ranges in the near infrared is superior to the visible
channels, particularly to the blue range. Longer wavelength spectral ranges that induce higher contrast
are therefore favored. Images of 3 spectral channels are fused and displayed for (pseudo) color
visualization, as an integrated high contrast video stream.
In addition to the dynamic optimization of the spectral channels, optimal real-time exposure time is
adjusted simultaneously and autonomously for each channel. A criterion of maximum average signal,
derived dynamically from previous frames of the video stream is used (Patent Application -
International Publication Number: WO2009/093110 A2, 30.07.2009). This configuration enables
dynamic compatibility with the optimal exposure time of a dynamically changing scene. It also
maximizes the signal to noise ratio and compensates each channel for the specified value of daylight
reflections and sensors response for each spectral range.
A possible implementation is a color video camera based on 4 synchronized, highly responsive, CCD
imaging detectors, attached to a 4CCD dichroic prism and combined with a common, color corrected,
lens. Principal Components Analysis (PCA) technique is then applied for real time "dimensional
collapse" in color space, in order to select and fuse, for clear color visualization, the 3 most significant
principal channels out of at least 4 characterized by high contrast and rich details in the image data.