PROBLEM TO BE SOLVED: To provide a mechanism to perform accurate tracking without increasing latency of arithmetic processing related to an amount of movement of a subject when a predetermined distortion is included in an image related to the subject.SOLUTION: An image acquisition device includes: an arithmetic region selection part 342 for calculating a feature amount according to a feature object of a subject included in each region about each region constituting a reference image which is an image having a predetermined distortion related to the subject acquired by an optical sensor 106, and serves as a reference in calculating an amount of movement of the subject, making a correction according to the predetermined distortion for the feature amount for each region, and selecting an arithmetic region used in calculating the amount of movement from each region constituting the reference image based on an evaluation value of the feature amount after the correction； and an amount-of-movement calculation part 344 for comparing the arithmetic region in the reference image with a corresponding region corresponding to the arithmetic region in a second image which is an image acquired by the optical sensor 106 and is different from the first image, and calculating the amount of movement of the subject.SELECTED DRAWING: Figure 3【課題】被検体に係る画像に所定の歪みが含有されている場合に、被検体の移動量に係る演算処理のレイテンシを増大させることなく、高精度なトラッキングを行える仕組みを提供する。【解決手段】光センサ１０６で取得された被検体に係る所定の歪みを有する画像であって被検体の移動量を演算する際の基準となる参照画像を構成する各領域について、当該各領域に含まれる被検体の特徴物に応じて特徴量を算出し、当該各領域ごとに特徴量に対して所定の歪みに応じた修正を行い、当該修正を行った後の特徴量の評価値に基づいて参照画像を構成する各領域の中から移動量を演算する際に用いる演算領域を選択する演算領域選択部３４２と、参照画像における演算領域と、光センサ１０６で取得された画像であって第１の画像とは異なる第２の画像における前記演算領域に対応する対応領域とを比較して、被検体の移動量を算出する演算を行う移動量演算部３４４を備える。【選択図】図３
