| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| WhiteRabbit | "Here's a write-up that I'm finding quite helpful: http://publiclab.org/notes/nedhorning/11-01-2013/why-a-red-filter-should-work-well-for-ndvi Eyeb..." | Read more » | over 10 years ago | |||
| WhiteRabbit | "Sounds like gel filters would be tricky at best, so I guess ixnay to that. How about this one? http://www.ebay.com/itm/Optical-Interference-Filter..." | Read more » | over 10 years ago | |||
| cfastie | "I have not seen a cheap filter like Rosco that is truly a narrow band pass filter. It might be possible to combine filters to get a fairly narrow t..." | Read more » | over 10 years ago | |||
| WhiteRabbit | "Cool! Awesome post. I suppose it's wishful (and probably foolish) thinking, but given the the low price of a filter swatch book and the seemingly..." | Read more » | over 10 years ago | |||
| cfastie | "A filter switcher is a viable solution, especially for small cameras. Cameras as large as Powershots might require a big, precise device in front o..." | Read more » | over 10 years ago | |||
| WhiteRabbit | "Thanks, Chris, for your thoughtful and very informative post. If I'm reading it right, perhaps using two monochrome cameras, each with the appropr..." | Read more » | over 10 years ago | |||
| cfastie | "It should be possible to distinguish between stressed and non-stressed lawn grass using NDVI. I suspect that the $900 FieldScout performs more or l..." | Read more » | over 10 years ago | |||
| WhiteRabbit | "Interestingly enough, I did just now find this $889 turf grass color meter which does, indeed, use NDVI! http://www.specmeters.com/nutrient-manage..." | Read more » | over 10 years ago | |||
| WhiteRabbit | "Thanks for the links. Supposedly grass also changes color as the soil loses moisture (IIRC, it becomes less green and more blueish?), and people c..." | Read more » | over 10 years ago | |||
| warren | "I think a lot of the challenge of using an Infragram camera well is the need for comparison. Comparing an area treated in one way with a "control" ..." | Read more » | over 10 years ago | |||
| warren | "Crude Oil Set # 1 shows the basic differences between petroleums / crude oils. This set comes with an information sheet and these 6 petroleum / cr..." | Read more » | over 10 years ago | |||
| warren | "One thing I didn't understand was that they are listing the input light at longer wavelengths than the fluorescence peaks they're looking for. I wa..." | Read more » | over 10 years ago | |||
| warren | "Update: photo of the samples from Crude Oil Set #1: " | Read more » | over 10 years ago | |||
| mathew | "Boom. " | Read more » | over 10 years ago | |||
| warren | "It occurred to me in talking with @stevie that samples we collect ought to be treated as "unknowns" -- i think these mail-order samples are directl..." | Read more » | over 10 years ago | |||
| stevie | "I did post the ones we were looking at on the page here: http://publiclab.org/wiki/oil-testing-kit#Parts+list Or the direct links to the ones we w..." | Read more » | over 10 years ago | |||
| warren | "Actually @stevie and @natalie are sourcing new bottles right now, maybe you can get in on the order. We're hoping to switch to nail polish bottles,..." | Read more » | over 10 years ago | |||
| bsugar | "would the ones from ebay that I posted in the comment above be a good replacement? Cats you say? Then the cat gobo is for sure 1000% necessary. W..." | Read more » | over 10 years ago | |||
| mathew | "you just want a beam. the other tops that are cats and stars and octopuses are not helpful. " | Read more » | over 10 years ago | |||
| bsugar | "also, the recommended laser pointer comes with 5 different tops. are those necessary or will the standard tops do? http://www.ebay.com/itm/405nm-..." | Read more » | over 10 years ago | |||
| mathew | "actually, we did buy out all the rest of their stock. " | Read more » | over 10 years ago | |||
| bsugar | "is this the one that is shown in the picture at the top? It's 45mm tall, and 3.5ml. http://www.ebay.com/itm/STANDARD-GLASS-CUVETTE-OPEN-TOP-WITH-..." | Read more » | over 10 years ago | |||
| bsugar | "American Science and Surplus is out of the square glass bottles: http://www.sciplus.com/p/WHITCAP-BOTTLE_48212 I called them and they said that th..." | Read more » | over 10 years ago | |||
| Henry0815 | "Hi Jeffrey, "Was there a reason you mostly used the green? A blue laser will excite a broader range of colors, since light can only excite colors a..." | Read more » | over 10 years ago |