Correction of Stray Light In Spectroradiometers and Imaging Instruments | NIST

Measurement errors from stray light, spectral or spatial, are inevitable and are often the dominant source of error in spectroradiometers and imaging radiometers/photometers. We have developed a simple matrix method for correcting spatial stray light in imaging instruments as well as spectral stray-light errors in spectrometers. The stray-light correction method is based on the characterization of an instrument for a set of spectral line spread functions (LSF) or a set of point spread functions (PSF) to derive the correction matrix. The correction is simply done by a matrix multiplication to the measured raw signals, and stray-light errors are reduced by one to two orders of magnitude. By using a stray-light-corrected instrument, significant reductions are expected in overall measurement uncertainties in radiometry, colorimetry, photometry and many other applications.