Problem to be solved: to extract the range of the pupil automatically and accurately from the moving picture data of the moving image reflected in the eyeball.When the moving image data reaches the binarization processing section 122, the first processing section 122b1 in the binarization processing section 122 binarizes a still image based on the still image data included in the moving picture data by using a provisional threshold from the maximum density value to the density value minimum, and has a large number of A temporary threshold still image is generated.The second processing section 122b2 specifies the range of the temporary threshold value in which the area in which the density in the provisional threshold still image is maximized is changed even if the temporary threshold value based on a large number of provisional threshold still images changes, and determines a specific threshold in the range.The binarization processing section 122 sets the provisional threshold still image digitized with a specific threshold value as a binary still image.In the binary still image, only the pupil becomes the maximum density.(5)【課題】眼球の映り込んでいる動画像についての動画像データから、自動的且つ正確に、瞳孔の範囲を抽出する。【解決手段】動画像データが二値化処理部１２２に届くと、二値化処理部１２２内の第１処理部１２２Ｂ１が、動画像データに含まれる静止画像データに基づく１つの静止画像に対して、濃度値極大から濃度値極小までの仮閾値を用いて二値化を行い、多数の仮閾値静止画像を生成する。第２処理部１２２Ｂ２は、多数の仮閾値静止画像に基づく仮閾値が変化しても仮閾値静止画像中の濃度が極大となっている面積が変化しない仮閾値の範囲を特定し、その範囲で特定閾値を決定する。二値化処理部１２２は、特定閾値で二値化された仮閾値静止画像を二値静止画像とする。二値静止画像では瞳孔のみが濃度極大となる。【選択図】図５（Ｂ）
