---
title: "A Formal Description for Two-Dimensional Patterns"
authors:
  - "Charles T. Zahn Jr."
doi: ""
url: "https://ijcai.org/proceedings/1969/54"
pdf: "https://ijcai.org/proceedings/1969/0054.pdf"
venue: "Proceedings of the First International Joint Conference on Artificial Intelligence"
year: 1969
pages: "621-628"
track: "Linguistic and Contextual Methods in Pattern Recognition"
keywords:
---

# A Formal Description for Two-Dimensional Patterns

Charles T. Zahn Jr.

*Proceedings of the First International Joint Conference on Artificial Intelligence*, pages 621-628.

## Abstract

A "structural description" for two-dimensional black and white patterns is defined as the set of contour lines for an appropriate function which fits the binary pattern. These contour lines are mutually nonintersecting closed polygonal curves with edges in only eight different directions and they represent the boundari e s between connected black and white areas of the pattern. Rigorous procedures are described to transform a "matrix pattern" into a "structural description" and vice versa. Advantages of this method for describing patterns previous to pattern recognition are discussed at some length.