Line Drawings' Depth Clues

Object recognition is an essential ability for our life. It is an effective way to explore the mechanism of human cognition. The viewpoint is the key of the object recognition research and has always been the hotspot of this field. A debate on viewpoint has dominated research in object recognition in recent years. Two major theories about the viewpoint are structural description model and image-based model. The two theories are based on different object representations, which is 2D (two-dimension) image or 3D (three-dimension) structure in memories.In this paper, it is thought that the object representation consists of 2D image and 3D structure. In four experiments, we analyzed the line drawings' depth clues and investigated the two representations' process and relationship. The conclusions are as follows:(1)Our object representation consists of 2D image and 3D structure. Therepresentation is multiple in memories.(2)The representations can transform each other. After combined the steady depth information, the 2D image representation can transform to the 3D structure representation. (3)The depth clues are very important to restoration of 3D. The effective extractof the steady depth information is necessary for the form of 3D object. (4)We can deal with various cognition objects, tasks, environment, for we have the multiple representation, which is an effective resolvent for the "object constancy" and the "cognition at multiple categorical levels".