Perturbations to an integrating sphere’s radiant uniformity by a protruding optical system are mapped. A sphere provides the Descent Imager–Spectral Radiometer sensor head (DISR SH), a practical platform for many of its subsystems’ calibrations, but the resulting nonuniformity threatens the goal of accurate radiometry. An apparatus with a nearly identical shape is built to measure the radiance variations. The radiance field is found to be very homogeneous (0–2% variations) over two-thirds of the sphere’s surface area, with larger excursions near the SH, away from active fields of view. This provides an accurate platform to transfer absolute calibrations.
© 2001 Optical Society of America
(120.0280) Instrumentation, measurement, and metrology : Remote sensing and sensors
(120.3150) Instrumentation, measurement, and metrology : Integrating spheres
(120.5630) Instrumentation, measurement, and metrology : Radiometry
Bashar Rizk, "Private life of an integrating sphere: the radiant homogeneity of the Descent Imager-Spectral Radiometer calibration sphere," Appl. Opt. 40, 2095-2101 (2001)