PROBLEM TO BE SOLVED: To measure a line of sight direction with high accuracy without increasing the size of a light projection means.SOLUTION: A light projection device 12 includes four or more point light sources arranged along the right-and-left direction such that at least one of point light source intervals each representing the distance between adjacent point light sources differs from the other point light source intervals. A Purkinje image candidate extraction part 26 extracts a plurality of high-luminance points linearly arranged along the right-and-left direction of high-luminance points extracted from an image of an eye region as a pattern indicating a Purkinje image candidate, and a Purkinje image decision part 28 decides whether or not the Purkinje image candidate is the Purkinje image of the light projection device 12 based on the total length of the pattern indicating the Purkinje image candidate, the number of the high-luminance points included in the pattern, and a high-luminance point interval representing the distance between the adjacent high-luminance points. If there is a lack high-luminance point, the Purkinje image decision part 28 interpolates the high-luminance point. A reference point setting part 30 sets a reference point based on the Purkinje image, and a line of sight direction calculation part 38 calculates the line of sight direction of an object person by the corneal reflection method by use of the reference point and the pupil center.COPYRIGHT: (C)2013,JPO&INPIT【課題】投光手段を大型化することなく、精度良く視線方向を計測する。【解決手段】投光装置12は、隣接する点光源間の距離を表す点光源間幅の少なくとも1つが他の点光源間幅と異なるように左右方向に沿って配列された4つ以上の点光源を備えている。プルキニエ像候補抽出部26は、眼領域の画像から抽出された高輝度点のうち、左右方向に沿った直線状に並ぶ複数の高輝度点を、プルキニエ像候補を示すパターンとして抽出し、プルキニエ像判定部28で、プルキニエ像候補を示すパターンの全長、パターンに含まれる高輝度点の数、隣接する高輝度点間の距離を表す高輝度点間幅に基づいて、プルキニエ像候補が投光装置12のプルキニエ像か否かを判定する。欠落している高輝度点があれば補間する。基準点設定部30は、プルキニエ像に基づいて基準点を設定し、視線方向算出部38で、基準点及と瞳孔中心とを用いて、角膜反射法により対象者の視線方向を算出する。【選択図】図1
