Abstract
When viewing a perspective picture, oftentimes some depicted objects will look distorted (Kubovy, 1986). How does vision use information for 3-D in a perspective picture when perceiving the dimensions of a depicted object? Juricevic & Kennedy (2006) proposed an Angle and Ratios Together (ART) theory, based on the ratio of the visual angles of the object's depth and width, and its direction from the central vanishing point on the horizon. Interestingly, the ART theory predicts that identical objects laid out on paths leading straight away from the observer will look different. We tested this with pictures of tiles on a ground plane. Supporting the ART theory, many of the tiles were judged as distorted. However, contrary to the ART theory's prediction, tiles along different paths looked identical. Here we propose two modified theories to account for the results. First, an Angles and Ratios Together with Elevation (ART-E) theory with factors: (1) the ratio of the visual angles of the tile's depth and width and, (2) the tile's elevation. Second, an Angles and Ratios Together with Orientation (ART-O) theory with factors: (1) the ratio of the visual angles of the tile's depth and width and, (2) the tile's orientation.