Late last year we released our first version NDVI converted cameras using Schott BG3 filters. Using those filters we were able to generate pseudo NDVI images with a single camera, building off the work of the Public Lab project. After working with faculty at the University of Boston and the MEASA Lab at KSU, we determined that we weren’t quite getting the best results possible with the BG3 filter glass. Unfortunately, no off the shelf filter glass seemed to do exactly what we needed, block out red light and allow NIR light to pass instead. Luckily, we were able to find a manufacturer to help us build a custom filter to our specifications, and the results are looking really good! Below are two images, the first taken by a camera with BG3 filter glass and the second taken by a camera with the new custom glass, the difference is clear.
BG3 Filter Glass
Custom Filter Glass
Aside from higher overall values, there is more differentiation and detail in the leaves and a larger difference compared to the non-organic background material. This is especially important for this type of camera. Since these are uncalibrated, pseudo NDVI images, what is really needed most is high differentiation so that comparisons can be made between the majority of plants and potential problem areas. The higher detail available now makes it possible to catch unhealthy plants sooner.
Custom Filter Transmittance vs Wavelength
The new filters will be priced at $39.99 for the filter alone (8.9×7.9mm, fits SX260 and S100 at least, potentially others) and$499.90 for a ready to go converted SX260 with CHDK. It’s a little cold to be doing any crop surveys here in the Northeastern US right now, I actually ended up killing those two plants after taking them outside for just a few seconds! We’ll be out and collecting imagery as soon as anything starts growing and I’ll post updates as they become available.
Comments
hi jeff
i want to know if this filter can be used for any camera or is to especific ????
@Hugues I think the glass for an NEX would be at least double but I'm not sure how much of the filter cost comes from glass area and how much comes from the cutting into pieces.. would have to get a new quote.
@Jesus True the NEX takes a much better picture than the SX260 but the IR-only interface is really clunky for UAS integration, I think. I prefer something with a cable like the NX1000, personally.
The A5000 would probably be pretty similar to the NEX and NX1000
Que buen aporte Jeff. Muchas Gracias!!
Guys, would be nice if we start thinking on sony A5000 ndvi conversion and trigger method. This camera will be perfect for uav mapping.
Jeff.
I think NEX5 is going to be the next standard camera onboard multicopters and planes. As far as I know SX260 is much worse in terms of image quality and it is an old camera now.
On top of that supporting NEX5 may give you automatic support to a wide variety of APS-C sensor equiped cameras?
I'm also a candidate for a converted NEX5. I will be starting an agriculture project in February and will need NDVI images. Would be great if I could reuse my existing gimbal and NEX5, rather than installing a new one for an already obsolete canon 260 camera.
What would be the current price for a filter glass on a NEX5 ? feel free to pm me eventually to discuss this. thx
How about a lens cut for a modded GoPro? http://www.back-bone.ca
It's a pretty big big market with lots of existing gimbals
If that happened I guess we'd move to the S100 which is a pretty easy switch. If both were gone for some reason we'd have to switch to another brand, but now that the trig_dist functionality is working on ArduPlane it wouldn't be all that painful. It would be unfortunate to lose the ability to close the camera lens but we'd just have to find a way to protect it better.
Hi Jeff,
Do you already have any plans for the case that Canon discontinues the HS 260 before CHDK is available for the HS 280? I'm a huge CHDK fan and I'm ordering your NDVI filter in bulk, but the unclear Canon/CHDK situation makes me wondering if I shouldn't switch to another camera like the Sony QX-100 any time soon.
Unfortunately the NEX5 would require a much larger piece of filter glass and these filters need to be bought in pretty significant quantity to even make them the price they are now. If there are a lot of people needing conversions on the NEX5 I'd certainly consider it, but since we don't use the NEX series on any of our RTF systems, I don't think we'll see enough demand in the near future to justify ordering larger filters.
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