Abstract

Computer vision techniques have been used extensively to automatically monitor human activities; however, applications for analysing animal behaviour are sparse. The analysis of bat behaviour in particular has attracted only one or two studies. Most existing work uses either expensive thermal imaging equipment, or bespoke sensors which are not accessible to field researchers, ecologists, and scientists studying behaviour. The work we present here uses spectral analysis techniques to quantify wingbeat frequency, using a single imaging device in low-light. We propose two modified techniques based on bounded box metrics, and similarity matrices, for measuring periodic and cyclical motion as a 1D time domain signal. These are transformed to the frequency domain using Short Time Fourier Transform (STFT). Finally we evaluate these techniques against the baseline algorithm proposed by Cutler and Davis [5], using expert-annotated ground-truth data.