ASCII Art Generation Using the Local Exhaustive Search on the GPU

An ASCII art is a matrix of characters that reproduces an original gray-scale image. It is commonly used to represent pseudo gray-scale images in text based messages. Since automatic generation of high quality ASCII art images is very hard, they are usually produced by hand. The main contribution of this paper is to propose a new technique to generate an ASCII art that reproduces the original tone and the details of an input gray-scale image. Our new technique is inspired by the local exhaustive search to optimize binary images for printing based on the characteristic of the human visual system. Although it can generate high quality ASCII art images, a lot of computing time is necessary for the local exhaustive search. Hence, we have implemented our new technique in a GPU to accelerate the computation. The experimental results shows that the GPU implementation can achieve a speedup factor up to 57.1 over the conventional CPU implementation.