Multispectral and hyperspectral analysis and modelling of the absorbance characteristics of marine algal pigments

Abstract

The techniques of remote sensing in spectral bands and hyperspectral remote sensing were modelled with laboratory experiments on marine algal pigments obtained from four species of green micro‐algae of the eastern coast of India. The spectral absorbance was measured within the visible range of wavelength for chlorophyll mixtures of different concentrations and also for chromatographically separated pigments. The intention was to simulate and compare the expected nature of results obtained with remote sensing in wavebands and hyperspectral sensing involving a fine resolution in wavelength. Therefore, the absorbance was measured both with filters of three different visible spectral bands, viz. blue, green, and red, and with a continuous scan of wavelength. The algal species were distinguishable with both types of measurements. However, the hyperspectral technique was found to be more suitable in revealing the individual contribution of pigments. Based on the experimental results, a computational model was developed with Gaussian variation of absorbance as a function of wavelength. The experimental results were simulated with that model explaining the comparative spectroscopic results obtained from band and hyperspectral sensing.

Acknowledgements

The authors wish to thankfully acknowledge the financial support of the Council of Scientific and Industrial Research (CSIR), New Delhi, India and the kind cooperation of the Principal and all the staff of the Departments of Physics and Botany of Presidency College, Kolkata, India.