@techreport{oai:ipsj.ixsq.nii.ac.jp:00053631,
 author = {徐剛 and 辻, 三郎 and Gang, Xu and Saburo, Tsuji},
 issue = {73(1988-CVIM-056)},
 month = {Sep},
 note = {「四辺形の視覚的解釈その1」で、四辺形を長方形として解釈することについて述べた。ここでは、重力をうける長方形の姿勢について述べる。重力を受けるものは何かによって支えられなければならない。それは重力の方向に垂直の地平面と知覚されることが多い。カメラと地面との関係、長方形と地面との関係を明らかにし、長方形の向きの拘束条件を得る。, We have proposed the rectangularity regularity to be prime constraint in the visual interpretation of quadrilaterals, by which quadrilaterals in image are interpreted as rectangles in space [Xu & Tsuji, 1988]. In this paper we propose another regularity, the gravity regularity. Everything, including the perceiver itself, is attracted by gravity. As a consequence, objects must be supported by something. It is usually perceived to be the ground plane, perpendicular to the direction of gravity, if no evidence indicates otherwise. This paper first analyzes the relation among the camera, the ground and the rectangles supported by the ground, and then derive constraints to determine the rectangle orientation.},
 title = {四辺形の視覚的解釈その2　－重力を受ける長方形の姿勢},
 year = {1988}
}