Enhancement and quality control of GOES images
GOES-8 and Beyond
The new generation of Geostationary Operational Environmental Satellites (GOES) have an Imager instrument with five multispectral bands of high spatial resolution, and very high dynamic range radiance measurements with 10-bit precision. A wide variety of environmental processes can be observed at unprecedented time scales using the new Imager instrument. Quality assurance and feedback to the GOES Project Office is performed using rapid animation at high magnification. examining differences
... en successive frames, and applying radiometric and geometric correction algorithms. Missing or corrupted scanline data occur unpredictably due to noise in the ground based receiving system. Smooth high resolution noisefree animations can be recovered using automatic techniques even from scanline scratches affecting more than 25% of the dataset. Radiometric correction using the local solar zenith angle was applied to the visible channel to compensate for time-ofday illumination variations to produce gain-compensated movies that appear well-lit from dawn to dusk and extend the interval of useful image observations by more than two hours. A timeseries of brightness histograms displays some subtle quality control problems in the GOES channels related to rebinning of the radiance measurements. The human visual system is sensitive to only about half of the measured 10-bit dynamic range in intensity variations. at a given point in a monochrome image. In order to effectively use the additional bits of precision and handle the high data rates new enhancement techniques and visualization tools were developed. We have implemented interactive image enhancement techniques to selectively emphasize different subranges of the 10-bits of intensity levels. Improving navigational accuracy using registration techniques and geometric correction of scanline interleaving errors is a more difficult problem that is currently being investigated.