Multispectral Aerial Plastic Imaging
How to monitor and remove the rapidly accumulating plastic pollution in our environment is increasingly recognised as a pressing global issue. While the problem has been well documented in certain areas, there is still a need for standardized, user-friendly methodologies that can be applied consistently in diverse locations.
When our eyes distinguish different colours, we are really perceiving light by a property called its wavelength. Different substances absorb and reflect different wavelengths of light, depending on their molecular composition. For example, leaves appear green because they contain chlorophyll, which absorbs red and blue wavelengths, whilst the green wavelengths are reflected. Humans are able to observe a certain subset of wavelengths, but this is only a tiny fraction of the full spectrum of wavelengths that light can have. Infrared (IR) light, for example, has a longer wavelength than humans are able to perceive. We are, however, able to build cameras that detect this ‘invisible’ light, and scientists can make use of this property!
Different types of plastics reflect and absorb different wavelengths of light. This information because especially useful when we consider light with wavelengths longer than the human eye can see. Here different plastic compositions- for example Styrofoam as compared to a plastic water bottle – reflect a very different set of wavelengths. Special cameras that detect this light, called hyperspectral cameras, can not only distinguish plastic from other materials, but also determine details of the plastic’s composition.
Scientists at the British Antarctic Survey, with whom we have partnered for this project, have experience using drone-based HSI for a variety of ecological and geological monitoring applications in polar regions, and in general the technique is well established in diverse fields such as agriculture and waste management. However, HSI is also well suited to detecting plastic, as different polymer compositions emit unique spectra. HSI can therefore reveal information about both the presence and the composition of plastic pollution.
Our project aims to develop existing technologies into a powerful new tool for remote monitoring of terrestrial plastic pollution. We are exploring drone–based hyperspectral imaging (HSI) as a tool to detect plastic pollution.We will test different commercially available cameras, drones, and software packages, with the goal of developing a user-friendly, cost effective monitoring tool, which could provide a more informative option to replace labour-intensive and low-throughput manual methods such as beach cleans.
- Sarah is a PhD student in the Department of Physiology, Development, and Neuroscience. She studies how neurons grow during development.
- Hannah is a PhD student in the Department of Physics. She studies the nutrient exchange between algae and bacteria.
- Jack is a PhD student in the Department of Engineering studying fluid mechanics with applications to geophysical flows in the environment.