Miniaturised Hyperspectral Imager for Remotely Piloted Aircraft Surveys

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The colour of an object, e.g. a tree or a field of grass, is controlled by the way in which light interacts with the material of the object (leaves, trunk, soil). By measuring the colour of an object (its reflectance spectrum), we can work out what materials are present, how much of them are there, and sometimes we can even work out whether they are healthy or dying. Spectral cameras are used to take images of objects from a distance using different colours (wavelengths) of light. By putting spectral cameras on satellites orbiting the Earth, we can monitor vast areas of the planet; whole oceans and continents. However spectral cameras on satellites are generally designed to cover big areas (wide swath) and many are not able to resolve small features below ~1km. Satellite cameras are also limited by being unable to see through clouds. This means we need a different vehicle to mount spectral cameras on for local studies of e.g. rivers, lakes, estuaries or for seeing high resolution images of fields and forests. Aircraft have been used to do this for many years, very successfully, but they are expensive to run and it is very hard to organise getting the aircraft out to a remote location at exactly the same time as people on the ground or on a boat. Recently a new type of remotely piloted aircraft (RPA - also known as a drone) has become cheap enough and reliable enough for it to be possible for individuals or small research groups to be able to afford to buy and operate them. These RPAs are small and easily launched and landed, and if we could make spectral cameras small enough to mount on them, they could be a really useful platform for high quality environmental surveys. This project will try to develop a small spectral camera that is light enough to be able to use it on an RPA. We will build the camera so that it is able to measure many different colours of light (e.g. 100 different colours - hyperspectral). We will use a new kind of optical filter to help keep the size and weight down and we will work with the Field Spectroscopy Facility in Edinburgh to make sure that the camera gives very accurate readings of the amount of light of each colour.