Classification of Bird Sound Using High-and Low-Complexity Convolutional Neural Networks

Abstract

Birds are a reflection of environmental health as pollution and climate change affect biodiversity. Experts in ecology and machine learning stand to benefit the most from largescale monitoring of biodiversity. Today, convolutional neural networks (CNNs) are the preferred choice for species recognition as their performance has consistently outperformed humans. However, CNNs are disadvantaged by their high computational complexity and the need to provide vast amounts of training data. This paper compares the performance versus the complexity of two widely used CNNs, namely ResNet-50 and MobileNetV1. ResNet-50 is a high-complexity CNN while MobilenetV1 is a low-complexity CNN targeted for mobile applications. We used spectrogram images of Brazilian bird sounds as inputs to both networks. These birds were chosen due to their abundance of samples in the Xeno-canto bird sound repository. Short-Time Fourier Transform (STFT) and Mel Frequency Cepstral Coefficient (MFCC) algorithms are used to extracting spectrogram images. To validate the precision of the classifier, 1,000 spectrogram images of each of ten bird species are produced and fed into both classifiers. The findings indicate that the accuracy of MobileNetV1 is close to that of ResNet-50, with MFCC which is 85.73 and 90.56 respectively.

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