Comments

Author Comment Last activity Moderation
btbonval "If PhotosynQ people want to make their own wiki, they're free to grab the content from your note here or the wiki page I made from your note. Every..." | Read more » about 7 years ago
btbonval "Stripped out all the juicy plant bits and spectral mumbo jumbo. added it here: http://publiclab.org/wiki/multispectral-analysis-for-determining-pla..." | Read more » about 7 years ago
btbonval "Apologies if I was being pedantic. Now that I think about it, cleaning up the note isn't a great solution. Instead of changing this note, the perti..." | Read more » about 7 years ago
btbonval "Woops I skipped the part at the top where it seems to suggest in advertisement language that the PhotosynQ gives you this and more! Any chance you..." | Read more » about 7 years ago
btbonval "This is a really good collection of information about photosynthesis and spectral analysis. My understanding was that NDVI has largely been used f..." | Read more » about 7 years ago
btbonval "I think it would be difficult to measure for heavy metals without interacting with the plant in some way, as the metals are unlikely to be hanging ..." | Read more » about 7 years ago
btbonval "As an example of something with low specific heat capacity, you could fill your fridge with metal pots. Although the pots won't fall out of the fri..." | Read more » about 7 years ago
btbonval "As a heads up, the contents of the refridgerator can make a huge difference. If you have a fridge with nothing in it at all, the fridge is only co..." | Read more » about 7 years ago
btbonval "Have you analyzed your different brew techniques using the Spectrometer? Do you think we would see the spectrum for flavor? " | Read more » about 7 years ago
btbonval "I just realized the images shown in the research note are thumbnails. The threshold enhancement helped the thumbnails a lot. Looking at the actual..." | Read more » about 7 years ago
btbonval "@amysoyka Yeah, that's pretty much what I meant. It worked way better than I would have thought. You can see wrinkles and bubbles in the tape! Inv..." | Read more » about 7 years ago
btbonval "The inverse helps make particles stand out. Another filter you might try is a threshold. If you're using GIMP (free and open source software for im..." | Read more » about 7 years ago
btbonval "This is looking good. I love the grid layout pattern. I see this is incomplete, but I wanted to let you know the black square (which has a slit cu..." | Read more » over 7 years ago
btbonval "I think part of the problem is that infrared light and visible light (and each subdivision thereof) are reflected differently at the interface of a..." | Read more » over 7 years ago
btbonval "Part of the issue here would be the IR reflectance of the water's surface (due to the index of refraction of the water/air boundary), which I under..." | Read more » over 7 years ago
btbonval "Talking about density, temperature, and floating makes me think of a Galileo thermometer: they are sealed with little glass beads that show the tem..." | Read more » over 7 years ago
btbonval "Canoes shouldn't create eddies that penetrate very deeply into the water current. Did the dye penetrate into the water or rest on top? If the dye ..." | Read more » over 7 years ago
btbonval "@warren @nemo @dorncox @cfastie @karenv I finally went through the ubiq show from Italian TV for screen caps. I also made a PL-specific cut of the..." | Read more » over 7 years ago
btbonval "On the plots, it looks like you have linearly sampled x-data, around 300 nm to 700 nm. The question is whether each x-value is equally spaced. If t..." | Read more » over 7 years ago
btbonval "@warren You aren't taking integrals, you're accumulating y-values. This might be equivalent if and only if the difference between x-value samples ..." | Read more » over 7 years ago
btbonval "In numpy, it'd be fairly easy. # establish that x and y are 1d vectors xdata = data[0,:] ydata = data[1,:] # perform cumulative sc..." | Read more » over 7 years ago
btbonval "If you have access to matrix math, I can vectorize the previous algorithm to speed it up. If you're in client javascript, I'm unaware of any good v..." | Read more » over 7 years ago
btbonval "Here's a dirty and slow way to determine the 50% mark: Firstly, normalize your data by dividing the integral (area under the curve). The area unde..." | Read more » over 7 years ago
btbonval "@stoft the centroid would be a point (x,y), not a line (x=B for all y). sorry to nitpick verbiage. I got all mathy in this post, figured I'd keep u..." | Read more » over 7 years ago