Abstract
A useful EPS (expanded polystyrene) integrating sphere for flat-field correction of CCD images has been made. Our integrating sphere has three new features. White LEDs and a 3-terminal regulator are used to get stable luminance. Inner wall of the integrating sphere is painted by Ba2SO4 powder (SAKAI CHEMICAL INDUSTRY CO., LTD.) to make diffusive reflection surface. A digital light meter is mounted at a regular position to monitor the change of luminance. Owing to these features, in spite of low cost, the integrating sphere is available not only for flat-field correction but for examination of linearity of optical sensors even in the open air.
