Theofilos Christodoulou, "Development of a hyperspectral microcamera", Diploma Work, School of Electrical and Computer Engineering, Technical University of Crete, Chania, Greece, 2018
https://doi.org/10.26233/heallink.tuc.72935
The purpose of this study is to test the feasibility of creating a hyperspectral imaging device, utilising a single rotating dichroic filter as a spectral scanning mechanism. Hyperspectral imaging stands for the acquisition of distinct spatial information from many, typically hundreds, individual spectral components within the electromagnetic spectrum. The examination of the spectral composition of light at each pixel of the image, namely spectral imaging, is able to provide qualitative and quantitative information about the physical and chemical structure of matter, in a non-invasive and non-destructive manner. The proposed system does not compromise spatial resolution, as it uses the entire sensor to capture spatial information at each exposure. A rotating dichroic filter acts as a tunable band-pass optical filter, used to selectively isolate spectral components and, eventually, scan across the electromagnetic spectrum. The ability to tune a dichroic mirror, derives from the nature of the angle of incidence as a determinative factor for its frequency response. In this particular design, a triple-band band-pass dichroic filter is used, along with a color camera, in order to reduce the total number of exposures needed to acquire the desired spectrum. The precise rotation of the filter is achieved using a Stepper motor, that is driven with an Arduino equipped with the Arduino Motor Shield. The proposed method is, ultimately, able to assist spectral imaging with remarkable scalability and optimal reusability of the optical and mechanical components of the device. Further optimisation of this system can lead to the construction of a compact, largely accessible, real- time hyperspectral imaging device.