Automatic ASCII Art conversion of binary images using non-negative constraints

It is hard to avoid ASCII Art in today's digital world, from the ubiquitous emoticons-;)-to the esoteric artistic creations that reside in many people's e-mail signatures, everybody has come across ASCII art at some stage. The origins of ASCII art can be traced back to the days when computers had a high price, slow operating speeds and low graphics capabilities, which forced computer programmers and enthusiasts to develop some innovative ways to render images using the limited graphics blocks available, viz., text characters. Here, we treat automatic ASCII art conversion of binary images as an optimisation problem, and present an application of our work on Non- Negative Matrix Factorisation to this task-where a basis constructed from monospace font glyphs is fitted to a binary image using a winner-takes-all assignment.