PROBLEM TO BE SOLVED: To allow a fundus image to be observed without a sense of incompatibility, and to obtain better fundus images by highly accurate focusing.SOLUTION: A focusing lens is moved for a moving amount Δf0 in S4, and pulse light emission by a photographing light source is performed in S5. The output of a captured fundus image by pulse light is converted into digital signals in S6, a contrast calculation is performed to calculate a contrast evaluation value Cn of the signals of prescribed frequency components in S7. The process is repeated 2m+1 times, and the moving amount Δfn of the focusing lens and the contrast evaluation value Cn are stored in association with each other in S8. When the prescribed number of times of pulse light emission ends in S3, sizes of respective contrast evaluation values C0-C2m are compared in S11, the moving amount Δfi of the focusing lens for the time of the largest contrast evaluation value Ci is obtained, and the focusing lens is moved to the position in S12. The photographing light source 16 is made to emit light to capture the fundus image in S13 and S14, and the fundus image is preserved and also displayed in S16.COPYRIGHT: (C)2014,JPO&INPIT【課題】違和感なく眼底像を観察でき、高精度なピント合わせにより良好な眼底像を得る。【解決手段】S4でフォーカスレンズを移動量Δf0だけ移動し、S5で撮影光源によるパルス発光を行う。撮像されたパルス光による眼底像の出力は、S6でデジタル信号化され、S7でコントラスト演算を行い、所定の周波数成分の信号のコントラスト評価値Cnを算出する。このことを、2m+1回繰り返して、S8でフォーカスレンズの移動量Δfnとコントラスト評価値Cnを関連付けて記憶する。S3で所定回数のパルス発光が終了すると、S11で各コントラスト評価値C0~C2mの大小を比較し、最も大きいコントラスト評価値Ciのときのフォーカスレンズの移動量Δfiを求め、S12でその位置に移動する。S13、S14で撮影光源16を発光させて眼底像を撮像し、S16で眼底像を保存すると共に表示する。【選択図】図2
