Correction of second order light for the HICO™ sensor onboard the international space satation

The Hyperspectral Imager for the Coastal Ocean (HICO™) is a new spaceborne sensor designed specifically for monitoring the turbid coastal waters and large inland lakes and rivers from the International Space Station (ISS). HICO™ is now collecting hyperspectral imaging data in the wavelength range of 0.4 - 1.0 micron with a spatial resolution of approximately 90 meters and a spectral resolution of 5.7 nanometers. During the construction of the HICO™ instrument, it was not possible to place a blocking filter in front of the CCD (Charge-coupled device) array located in the focal plane. As a result, the second order light from the shorter visible spectral region falls onto the detectors covering the near-IR spectral region above 0.8 micron. In order to have accurate radiometric calibrations of the near-IR channels, the second order light effects need to be removed. Through analysis of HICO™ imaging data containing features of shallow underwater objects, such as coral reef, we have developed a new empirical technique to correct for the second order light effects. HICO™ data acquired over Midway Island, Key Largo, Bahamas Bay and Philippine Sea are used to demonstrate the effectiveness of the new technique.