Industrie - Sketches 2

Résumé :

An important question for both signal processing and auditory science is to understand which features of a sound carry the most important information for the listener. Here we approach the issue by introducing the idea of “auditory sketches”: sparse representations of sounds, severely impoverished compared to the original, which nevertheless afford good performance on a given perceptual task. Starting from biologically-grounded representations (auditory models), a sketch is obtained by reconstructing a highly under-sampled selection of elementary atoms. Then, the sketch is evaluated with a psychophysical experiment involving human listeners. The process can be repeated iteratively. As a proof of concept, we present data for an emotion recognition task with short non-verbal sounds.

We investigate

1. the type of auditory representation that can be used for sketches
2. the selection procedure to sparsify such representations
3. the smallest number of atoms that can be kept
4. the robustness to noise.

Results indicate that it is possible to produce recognizable sketches with a very small number of atoms per second. Furthermore, at least in our experimental setup, a simple and fast under-sampling method based on selecting local maxima of the representation seems to perform as well or better than a more traditional algorithm aimed at minimizing the reconstruction error. Thus, auditory sketches may be a useful tool for choosing sparse dictionaries, and also for identifying the minimal set of features required in a specific perceptual task.