Where to draw the line?

Heping Sheng,Dirk B Walther,John Wilder,Markus Lappe

doi:10.1371/journal.pone.0258376

Abstract

We often take people's ability to understand and produce line drawings for granted. But where should we draw lines, and why? We address psychological principles that underlie efficient representations of complex information in line drawings. First, 58 participants with varying degree of artistic experience produced multiple drawings of a small set of scenes by tracing contours on a digital tablet. Second, 37 independent observers ranked the drawings by how representative they are of the original photograph. Matching contours between drawings of the same scene revealed that the most consistently drawn contours tend to be drawn earlier. We generated half-images with the most- versus least-consistently drawn contours and asked 25 observers categorize the quickly presented scenes. Observers performed significantly better for the most compared to the least consistent half-images. The most consistently drawn contours were more likely to depict occlusion boundaries, whereas the least consistently drawn contours frequently depicted surface normals.

Highlights

Humans have used line drawings to depict scenes from their lives for at least 45,500 years [1]
In the three experiments presented here we have established that (1) line drawings are rated as more representative of the depicted scene when they are drawn by experienced artists; (2) the most consistently drawn contours are drawn earlier; (3) drawings containing the most consistently drawn contours are more recognizable than drawings with the least consistently drawn contours; and (4) the most consistent contours are more likely than inconsistent contours to represent occlusion boundaries, that is, the boundaries of objects
While these results may seem unsurprising in hindsight, this is the first time, to our knowledge, that the ability of humans of various levels of artistic expertise to convey essential information in line drawings has been quantitatively measured for complex real-world scenes

Summary

Introduction

Humans have used line drawings to depict scenes from their lives for at least 45,500 years [1]. Line drawings can capture the essence of shapes and spatial relationships in complex scenes to an extent that makes them reasonable stand-ins for photorealistic images, but can emphasize particular aspects of the scene unencumbered by other, extraneous features that might otherwise obscure the clarity arising from a purely contour-driven depiction. For this reason, line drawings are used for technical drawings, such as architectural plans, designs for complex machinery, or charts for complex production processes.

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Results

Conclusion