Homebrew Camera Mod Mimics LANDSAT Satellite

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A simple, cheap infrared camera which can measure plant health -- for geek gardeners, farmers, and open source DIY scientists.

What is Infragram?

Infragram is a simple, affordable near-infrared camera produced by the Public Laboratory community in a series of collaborative experiments over the last few years. We originally developed this technology to monitor wetlands damages in the wake of the BP oil spill, but its simplicity of use and easy-to-modify open-source hardware & software makes it a useful tool for home gardeners, hikers, makers, farmers, amateur scientists, teachers, artists, and anyone curious about the secret lives of plants.

 

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  • Martin!! Que pasa! 

    Thanks for the invitation, would love to come (and fly?) in Costa Rica! Pura Vida..

    Regarding other camera's, all come with their benifits and disadvantages, but I did not yet found the ideal solution to mount under a small UAV system. Or you have a problem with co-registration of bands (in case of different lens system or adaptive filter systems) or you have a problem with georeferencing due the low accuracy GPS/IMU for line scanning systems. All are not bad systems, just people need to know what kind of extra measurements or post-processing they need to apply before having a workable product.

    New camera system which I am really looking forward to because of its on-chip filter technology and specific sensor design:

    http://www.vito.be/VITO/EN/HomepageAdmin/Home/Nieuws/Persbericht/pe...

  • You are right Dries !!!
    It is not that simple to make a tetracam... the concept is simple... taking it to life is not so simple.

    (Personal message to Dries)... I´m now living in Costa Rica... if you ever come here... just let me know.

  • I am glad it was posted again. Just yesterday I was discussing an application with some people that would require about this level of analysis. While few would reasonably suggest this will replace million dollar satellites, it is enough to allow a dedicated group of self motivated developers to perhaps create something none of US would have thought of. Every once in a while the OS community does some pretty amazing stuff. Keep up the good work

  • @ Dries, I am glad you posted your comment. I think too many folks think its just a given that these types of DIY camera systems work just as good a more established and expensive cameras designed specifically to be remote sensing instruments.

  • True.. I have seen this post to many times not react.  Although I like the initiative to move forward in such DIY camera design for vegetation monitoring, there is a big difference of what comes out of these cameras and high-end earth observation sensors like LANDSAT, SPOT VEGETATION or others. To name a few:

    LANDSAT -OLI is a multispectral sensor with 9 bands in the visual, NIR and SWIR domain. Those bands, as defined by their central wavelength and FWHM, were chosen specifically to meet a broad range of applications (vegetation monitoring being one) and to cope with the difficult task of atmospheric correction.  The INFRAGRAM or other home-brewed sensors, has only 3 bands, a very broad green, blue and “NIR” band, which were not chosen specifically for vegetation monitoring, but merely to what is available in the local camera store.

    LANDSATs NIR band (5) is defined from 0.85 - 0.88 µm, right on top of the NIR spectral plateau where we can expect maximal scattering due to internal vegetation cell structure. The NIR band of the INFRAGRAM is defined by the camera’s sensitivity around 720nm (which is blocked in normal camera) and the transparency at the same wavelength of the “super blue filter” they put in front. This 720nm is right in the middle between low reflection characteristic in the red (due to pigment absorption) and high reflection at the NIR (due to cell structure scattering). This is what we call the “red edge”. Hyperspectral sensors use the position of this red edge to derive more information about vegetation health status, but you need at least a measurement around 800nm to derive meaningfull data. If you want to see a spectral respons of a healty vs infected leaves, click here and check the wavelengths!!

    http://openi.nlm.nih.gov/detailedresult.php?img=3274483_1746-4811-8...

    LANDSAT is a pushbroom sensor calibrated in an integrating sphere to relate digital numbers (DN) to a value of real physical meaning, ie radiance values. After modelling the scene illumination conditions and atmospheric contributions they are able to derive reflection values, which are object specific and not related to external factors.  The INFRAGRAM (frame) camera gives you plain DN. They indicate to “calibrate” the camera before you take-off, but illumination conditions are surely not identical on the ground vs in the air.

    That leads us to the “NDVI” calculations: NIR-RED/NIR+RED. With NIR the spectral reflection value (not DN around 720!) around 800nm and RED the spectral reflection value around 650nm (so not a DN derived from a BLUE band in case of the infragram camera). As such I would not call the infragram vegetation index NDVI, maybe DIYVI?

    More information, go and take a peek here or contact me via PM

    http://hyperspectral.vgt.vito.be/content/vitos-hyperspectral-research

     

    Again, like the project,  but use the data with care!

    Dries

  • ahh true sorry. :-( but maybe someone miss seeing  it like me hehe.

  • Moderator

    This has been posted before twice... But its a good cause.

This reply was deleted.