3D Shape: Its Unique Place in Visual Perception

The uniqueness of shape as a perceptual property lies in the fact that it is both complex and structured. Shapes are perceived veridically -- perceived as they really are in the physical world, regardless of the orientation from which they are viewed. The constancy of the shape percept is the sine qua non of shape perception; you are not actually studying shape if constancy cannot be achieved with the stimulus you are using. Shape is the only perceptual attribute of an object that allows unambiguous identification. In this first book devoted exclusively to the perception of shape by humans and machines, Zygmunt Pizlo describes how we perceive shapes and how to design machines that can see shapes as we do. He reviews the long history of the subject, allowing the reader to understand why it has taken so long to understand shape perception, and offers a new theory of shape.

Until recently, shape was treated in combination with such other perceptual properties as depth, motion, speed, and color. This resulted in apparently contradictory findings, which made a coherent theoretical treatment of shape impossible. Pizlo argues that once shape is understood to be unique among visual attributes and the perceptual mechanisms underlying shape are seen to be different from other perceptual mechanisms, the research on shape becomes coherent and experimental findings no longer seem to contradict each other. A single theory of shape perception is thus possible, and Pizlo offers a theoretical treatment that explains how a three-dimensional shape percept is produced from a two-dimensional retinal image, assuming only that the image has been organized into two-dimensional shapes. Pizlo focuses on discussion of the main concepts, telling the story of shape without interruption. Appendixes provide the basic mathematical and computational information necessary for a technical understanding of the argument. References point the way to more in-depth reading in geometry and computational vision.

形狀作為一種知覺特性的獨特之處在於它既複雜又有結構。形狀被視為真實存在於物理世界中的，無論從哪個角度觀察都是如此。形狀知覺的恆常性是形狀知覺的必要條件；如果使用的刺激無法實現恆常性，則實際上並未研究形狀。形狀是物體唯一的知覺特性，可以進行明確的識別。在這本專門探討人類和機器對形狀知覺的第一本書中，Zygmunt Pizlo描述了我們如何感知形狀以及如何設計能夠像我們一樣看到形狀的機器。他回顧了這一主題的悠久歷史，使讀者能夠理解為什麼要花這麼長時間才能理解形狀知覺，並提出了一個新的形狀理論。

直到最近，形狀被與深度、運動、速度和顏色等其他知覺特性結合起來研究。這導致了明顯矛盾的研究結果，使得對形狀的一致理論處理變得不可能。Pizlo認為，一旦形狀被理解為視覺特性中的獨特存在，並且形狀知覺的知覺機制被視為與其他知覺機制不同，形狀研究就變得一致，實驗結果不再相互矛盾。因此，形狀知覺的單一理論是可能的，Pizlo提供了一個理論性的處理，解釋了如何從二維視網膜圖像中產生三維形狀知覺，假設圖像已經被組織成二維形狀。Pizlo專注於主要概念的討論，以不中斷地講述形狀的故事。附錄提供了基本的數學和計算信息，以便技術理解論點。參考文獻指引了更深入的幾何和計算視覺閱讀資料。