Abstract
Near infrared (NIR) remote sensing has applications in vegetation analysis as well as geological investigations. For extra-terrestrial applications, this is particularly relevant to Moon, Mars and asteroid exploration, where minerals exhibiting spectral phenomenology between 600 and 800 nm have been identified. Recent progress in the availability of processors and sensors has created the possibility of development of low-cost instruments able to return useful scientific results. In this work, two Raspberry Pi camera types and a panchromatic astronomy camera were trialed within a pushbroom sensor to determine their utility in measuring and processing the spectrum in reflectance. Algorithmic classification of all 15 test materials exhibiting spectral phenomenology between 600 and 800 nm was easily performed. Calibration against a spectrometer considers the effects of the sensor, inherent image processing pipeline and compression. It was found that even the color Raspberry Pi cameras that are popular with STEM applications were able to record and distinguish between most minerals and, contrary to expectations, exploited the infra-red secondary transmissions in the Bayer filter to gain a wider spectral range. Such a camera without a Bayer filter can markedly improve spectral sensitivity but may not be necessary.
Highlights
Average digital number (DN) measurements at 50 nm intervals identified the ZWO camera to be most sensitive to the spectral phenomenology of the Hematite sample, while the values of both RPi cameras were comparable
A pushbroom sensor built from three of the five consumer-grade imaging sensors identified from a tailored system engineering trade study were tested using materials exhibiting spectral phenomenology in the 600–800 nm region
Three commercial-grade sensors were used to trial a diffractive pushbroom sensor design against materials exhibiting spectral properties in the 600–800 nm range. This was conducted in order to identify the utility of popular Raspberry Pi cameras and a low-cost astrophotography camera for investigating materials that exhibit VIS/Near infrared (NIR) reflectance properties, and can be used in space analogue environments
Summary
Optical spectrometers have been invaluable instruments for understanding the physical properties of materials for the past two centuries [1]. Able to return information across parts of the spectrum in broad channels, these bands are limited such that subtle absorption characteristics are often missed, as this information is merged with other data within the channels to which the sensor is sensitive. This in turn limits the effectiveness of these instruments in identifying and characterizing mineralogy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
