Hi guys and congrats on this project, it's amazing! I'd like to know if it would be possible to take imagery from a drone using your spectrometer with a high quality cam?
I'm a marine biologist and we use a (very) expensive hyperspectral sensor on-board an aircraft to get some images from lagoon etc. From the reflectance spectrum, we can identify the habitat (sand, algae, type of corals etc.). I'd like to equip a drone with a spectrometer to collect images along predefined tracks. I was wondering if this would be feasible using this spectrometer. As it's for marine applications, we don't need wavelengths higher than the red (absorbed in the first mm). To make it short:
- Can we use the spectrometer for outdoors applications?
- If so, is it possible to select the wavelengths to scan?
- From the wiki, I understand that you can take 20-30 samples per second so if I scan from 390 to 600 nm with a 3 nm step, it means that it would take about 4 sec to get an image?
Thanks!
Sylvain
Hi Sylvain,
I don't know the answer to this question because I don't quite understand hyperspectral scanning. But I think the answer is maybe. The type of spectrometer Public Lab uses does not scan through the wavelengths. It takes a photo of the diffraction pattern formed by an entrance slit and grating. The light intensity at each wavelength is recorded in a spectrogram (the photo) which can be graphed as brightness at each wavelength. If you point the spectrometer at different colored surfaces, the light reflected from those surfaces will form diffraction patterns which will differ from each other as the apparent color of the surfaces differ. So assuming that the source of illumination (the sun in this case) does not change between photos, differences among spectra could reveal color differences among surfaces.
Each spectrogram (photo of diffraction pattern) can be analyze later to determine how bright each wavelength was, so you can choose whichever wavelengths you want to study (mostly between 400 and 700 nm). The intensity at each wavelength is garbled by the color system in consumer digital cameras, so there is not a one-to-one relationship between intensity at each wavelength and the actual spectral brightness in the scene. But you might be able to work around that with some calibration targets.
Chris
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