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Author Comment Last activity Moderation
LaPa "Hi, 1) unluckily I don't have access to a spectrometer 2) wich are the companies where I can buy a cheap Calibration targets? 3) may it be fine to ..." | Read more » over 6 years ago
LaPa "Thank you Chris, I'm going to read with the attention the Ned Horning's note that you link! Have a good day! LaPa " | Read more » over 6 years ago
cfastie "Sorry I missed some questions. Calibration targets work outside or in a greenhouse. Calibration targets are hard to find and very expensive. But ..." | Read more » over 6 years ago
LaPa "Hi, could it be a good idea to choose as calibration target the bare soil area that is in each (thousands) photos? Best regards LaPa " | Read more » over 6 years ago
LaPa "1) Could be a good idea put the calibration targets of known spectral reflectivity in Greenhouse to include in the photos ? 2) Where can I get the..." | Read more » over 6 years ago
cfastie "NDVI is based solely on color (near infrared is one of the colors). If a camera records different colors for two leaves, the NDVI computed for tho..." | Read more » over 6 years ago
LaPa "Thank a lot all of you for the consideration and the suggestions! Chris, sincerely I didn't understand from your reply if you consider my directio..." | Read more » over 6 years ago
liz "Hi @LaPa, great to see your note! I'm tagging some other raspberry pi developers @rjstatic and @seankmcginnis " | Read more » over 6 years ago
cfastie "Hi LaPa, Your time-lapse videos are impressive. These are excellent teaching videos. You can clearly see that the NDVI values for the foliage of t..." | Read more » over 6 years ago
cfastie "other areas (not foliage) showed values between 0.2 and 0.9 and I don't know why, since there is no photosynthesis occuring there. Getting high ND..." | Read more » over 6 years ago
ajawitz "RE:Any Radio? Wow! I had no idea! That could definitely be really useful if you already have compatible equipment for another purpose RE:OpenCPN..." | Read more » about 7 years ago
danbeavers "An additional site http://www.discriminator.nl/ais/index-en.html and http://www.discriminator.nl/index-en.html show how to do it with any radio tha..." | Read more » about 7 years ago
khufkens "Thanks Mathew for the link back! The whole package should work perfectly now, I'm still working on implementing the input output part, where I can..." | Read more » over 7 years ago
mathew "sounds cool. here's the link back to the context and description of PhenoPi http://publiclaboratory.org/notes/khufkens/04-24-2015/phenopi-a-citiz..." | Read more » over 7 years ago
khufkens "There are three variables in this setup: 1) the light source's output, which needs to be characterized or idealized (you could use the sun as a re..." | Read more » over 7 years ago
warren "Uh, perhaps I am not fully understanding on my initial readthrough, but since we have a big need to characterize sensitivity in the webcams we use ..." | Read more » over 7 years ago
khufkens "If I can back out the spectral response I'll post it online for sure. So give it some time. " | Read more » over 7 years ago
DarylWM "Thanks for sharing your work. I've had the same trouble trying to find the spectral response curve for the OV5647 sensor, so this technique was ver..." | Read more » over 7 years ago