khufkens 9 research notes and 9 wiki edits | Joined about 4 years ago | Moderator

I’m a research associate at Harvard University where my time is divided between modelling plant phenology across various biomes in response to climate change, being the lab geek and intrepid open source hardware and software developer.










PhenoPi: beta software installer release

by khufkens about 4 years ago | 2 | 1,360 views | 1



The accidental raspberry pi spectrometer

by khufkens about 4 years ago | 4 | 2,316 views | 4




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"Thanks for the contributions as well!! " | Read more » over 3 years ago
"thanks @matthew, seems like you have to include http otherwise the markup thinks it's an internal references. " | Read more » over 3 years ago
"http://www.flir.com/uploadedFiles/CVS_Americas/Cores_and_Components_NEW/Resources/flir-lepton-datasheet.pdf : says, 8 to 14 μm which seems to be to..." | Read more » over 3 years ago
"@marlokeno It's not cheap (although it's $100 than it used to be, mmm) but it sure is DIY and within the larger amateur budget. https://www.sparkf..." | Read more » over 3 years ago
"On the raspberry pi camera there is no real focus, so you either unscrew the lens assembly (google macro lens / macro photography and raspberry pi ..." | Read more » over 3 years ago
"I assume the optical properties of the chip should be relatively consistent, however optics might interfere a bit (create wavelength dependent loss..." | Read more » over 3 years ago
"Further, note that these values are scaled between 0-100% while the true QE peaks at an efficiency of 53.6% in the blue channels respectively. Rela..." | Read more » over 3 years ago
"Side note: the above assumes that the OmniBSI chipset as displayed in the documentation is the one residing in the OV5647, which is highly likely b..." | Read more » over 3 years ago
"What is described above is hardware development approached as current day software development. You have a main trunk (project lead) which is forke..." | Read more » over 3 years ago
"Ah, right around my corner. Nice... " | Read more » over 3 years ago
"I'm busy with work for the moment and have little time for my side projects. I'll probably pick it up again somewhere in autumn. I contacted some p..." | Read more » over 3 years ago
"Questions: What is your input and can you show the input data as well (mainly the red and near infrared images)? What software did you use to con..." | Read more » almost 4 years ago
"@cfastie, thanks for this write-up on some of the issues that plague the cheaper approaches to VI. I'm not sure people are aware of this and this m..." | Read more » almost 4 years ago
"Good point, I might use this approach to see if I can get better results on my PRI sensor. Things were funky and this offset in response (differenc..." | Read more » almost 4 years ago
"This is again a reason why you would want to know the spectral response of most imaging sensors. Without this information it will require field val..." | Read more » almost 4 years ago
"I'm not sure how you want to build an IR spectrometer using this method. I highly suggest reading the general description on infrared spectroscopy ..." | Read more » almost 4 years ago
"@gbathree, this wasn't as much a critique on the technique, but personal experience has taught me that you have to be really picky on how you alloc..." | Read more » almost 4 years ago
"As far as I understood is the value light use efficiency value (LUE / phi2) you measure by using PAM fluorescence (LUEpam) conceptually the same as..." | Read more » almost 4 years ago
"I'm confused by the goal of the experiment. Would just measuring Fv/Fm / or related values on a dark adapted leave not be quicker and more accurate..." | Read more » almost 4 years ago
"I just checked the float image I created earlier this week and it seems that all negative values are clipped on my float images as well, leaving th..." | Read more » about 4 years ago
"Also have a look at the histograms of both initial float images. You might be stretching your data somehow, leaving the majority of the pixels blac..." | Read more » about 4 years ago
"Do you pull those into an application which can handle images with floats? To make sure if both images are the same just plot them in a scatter plo..." | Read more » about 4 years ago
"Thanks @cfastie for reminding me of the Raleigh scattering, my equally scattered Sunday evening brain didn't quite put two and two together. The re..." | Read more » about 4 years ago
"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 » about 4 years ago








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