authors 
Gips, James Elliot 
year 
1974 
title 
Shape grammars and their uses : artificial perception, shape generation and computer aesthetics 
source 
Stanford University 
summary 
Shape grammars are defined and their uses investigated. Shape grammars provide a means for the recursive specification of shapes. The formalism for shape grammars is designed to be easily usable and understandable by people and at the same time to be adaptable for use in computer programs. Shape grammars are similar to phrase structure grammars, which were developed by Chomsky. Where a phrase structure grammar is defined over an alphabet of symbols and generates a language of sequences of symbols, a shape grammar is defined over an alphabet of shapes and generates a language of shapes. The dissertation is divided into three sections and an Appendix.In the first section: Shape grammars are defined. Some simple examples are given for instructive purposes. Shape grammars are used to generate a new class of reversible figures. Shape grammars are given for some wellknown mathematical curves (the Snowflake curve, a variation of Peano's curve, and Hubert's curve). To show the general computational power of shape grammars, a procedure that given any Turing machine constructs a shape grammar that simulates the operation of that Turing machine is presented. Related work on various formalisms for picture grammars is described. A symbolic characterization of shape grammars is given that is useful for implementing shape grammars in computer programs. In the second section, a program that uses a shape grammar to solve a perceptual task is described. The task involves analyzing and comparing line drawings that portray three dimensional objects of a restricted type. The third section is divided into two parts. First, a formalism for generating paintings is defined. The primary component of this formalism is a shape grammar. The paintings generated are material representations of shapes specified by shape grammars. The computer implementation of this formalism is described. The second part is concerned with aesthetics. A formalism is defined for specifying an aesthetic viewpoint. The formalism is used to specify a particular aesthetic viewpoint for interpreting and evaluating paintings generated using shape grammars. This viewpoint has been implemented on the computer. The net result is that the program described in Section 3 can be used to interactively define the rules for producing a painting, can use the rules to generate and display the resulting painting, and can then evaluate the painting relative to the specific aesthetic viewpoint. Relationships between the formalism for aesthetic viewpoints and information theory and science are touched upon. Finally, the possibility of using this approach to aesthetics to write programs that automatically analyze presented art objects or design new art objects is explored. In the Appendix, a method for constructing the inverse of a Turing machine is presented. This construction was created in response to a problem that is described in the aestheticssection. 
keywords 
Formal Languages; Computer Art; Aesthetics; Data Processing 
series 
thesis:PhD 
email 
gips@bc.edu 
more 
http://jenson.stanford.edu 
references 
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last changed 
2003/02/12 21:37 
