Spectrographs are used in a variety of applications in the field of remote sensing for radiometric measurements due to the benefits of measurement speed, sensitivity, and portability. However, spectrographs are single grating instruments that are susceptible to systematic errors in instrument calibration and in source measurements arising from stray radiation within the instrument. In the application of measurements of ocean color, stray light of the spectrographs has led to significant measurement errors. In this work, a simple method used to correct a spectrograph s measured raw spectral signals for stray-light errors is described. By measuring a set of monochromatic laser sources that cover the instrument s spectral range, the instrument s stray-light property is characterized and a stray light correction matrix is derived. The matrix is then used to correct the stray-light error in every measured raw signal by a simple matrix multiplication. Validation measurements demonstrate the efficacy of the method: the stray-light errors in a broad-band source measurement were reduced by one to two orders of magnitude, to a level equivalent to one count or less of a 15 bit resolution instrument after applying correction using the stray-light correction matrix.
Proceedings Title: Proceedings| Optics & Photonics | 2005
Conference Dates: July 31-August 4, 2005
Conference Title: SPIE
Pub Type: Conferences
correction, laser, ocean color, radiometry, remote sensing, spectrograph, spectrometer, spectroradiometer, stray light