---
title: "Extraction of the Line Drawings of 3-Dimensional Objects by Sequential Illumination From Several Directions"
authors:
  - "Yoshiaki Shirai"
  - "Saburo Tsuji"
doi: ""
url: "https://ijcai.org/proceedings/1971/8"
pdf: "https://ijcai.org/proceedings/1971/0008.pdf"
venue: "Proceedings of the Second International Joint Conference on Artificial Intelligence"
year: 1971
pages: "71-78"
track: ""
keywords:
---

# Extraction of the Line Drawings of 3-Dimensional Objects by Sequential Illumination From Several Directions

Yoshiaki Shirai, Saburo Tsuji

*Proceedings of the Second International Joint Conference on Artificial Intelligence*, pages 71-78.

## Abstract

The extraction of the line drawing of }-dimensional objects presented here is developed for the eye of the intelligent robot studied in the Electrotechnical Laboratory. This procedure consists mainly of two processes. First, four line drawings of the same objects illuminated from four different directions are sequentially obtained. Second, by applying 2-dimensional logical operations to these line drawings, a complete one is extracted. This method is applicable to more then two polyhedrons in a scene which is difficult by usual methods heretofore presented because of too small difference of light intensities between · two different planes or the effects of shadows.