The Feasibility of Automated Identification of Six Algae Types Using Feed-Forward Neural Networks and Fluorescence-Based Spectral-Morphological Features

Abstract

Harmful algae blooms are a growing global concern since they negatively affect the quality of drinking water. The gold-standard process to identify and enumerate algae requires highly trained professionals to manually observe algae under a microscope. Therefore, an automated approach to identify and enumerate these micro-organisms is needed. This research investigates the feasibility of leveraging machine learning and fluorescence-based spectral-morphological features to enable the identification of six different algae types in an automated fashion. A custom multi-band fluorescence imaging microscope is used to capture fluorescence data of water samples at six different excitation wavelengths ranging from 405 to 530 nm. Automated data processing and segmentation were performed on the captured data to isolate different micro-organisms from the water sample. Different morphological and spectral fluorescence features are then extracted from the isolated micro-organism imaging data and is used to train neural network classification models. The experimental results using three different neural network classification models (one trained on morphological features, one trained on fluorescence-based spectral features, and one trained on fluorescence-based spectral-morphological features) showed that the use of either fluorescence-based spectral features or fluorescence-based spectral-morphological features to train neural network classification models led to statistically significant improvements in identification accuracy when compared to the use of morphological features (with average identification accuracies of 95.7% ± 3.5% and 96.1% ± 1.5%, respectively). These preliminary results are promising and illustrate the feasibility of leveraging machine learning and fluorescence-based spectral-morphological features as a viable method for automated identification of different algae types.