PROBLEM TO BE SOLVED: To prevent a color tone of a taken image from being changed because the spectral distribution of a light source for illumination is changed with time.SOLUTION: An image is taken in an imaging element 14 by using light of the light source 21 as illumination, and a white balance of the taken image is adjusted in a pre-image-signal processing circuit 18. A beam splitter 31 is arranged on an optical path leading to a light guide 22 from the light source 21, and a light flux of the light source 21 is partially received by a light-receiving sensor 32. Tristimulus values actually measured by the light-receiving sensor 32 are compared with reference values of tristimulus values recorded in memory 34, and a change in the spectral distribution of the light source 21 is detected. On the basis of this, an R-gain and a B-gain in white balance processing are corrected to prevent the color tone of the taken image from being changed due to the change of the spectral distribution.COPYRIGHT: (C)2013,JPO&INPIT【課題】照明用光源の経時的な分光分布の変化による撮影画像の色調変化を防止する。【解決手段】光源21の光を照明として撮像素子14において画像を撮影し、前段映像信号処理回路18において撮影画像のホワイトバランスを調整する。光源21からライトガイド22に至る光路上にビームスプリッタ31を配置し、光源21の光束の一部を受光センサ32において受光する。受光センサ32で実測された3刺激値とメモリ34に記録された3刺激値の基準値とを比較し、光源21の分光分布変化を検出する。これに基づきホワイトバランス処理におけるR、Bゲインを補正し、分光分布が変化したことによる撮影画像の色調の変化を防止する。【選択図】図1
