I am new to this site but better late than never:)
I like to use a small uav that is equipped with a near infrared camera to take images of various crops showing stressed vs non stressed vegetation (Infrared is good for this purpose). The camera I found is only 7 onces (about 200 g) and it calls for GPS intput to be a true +/-RS232. Additionally, I would like my UAV to be independent in term of missions so that a minimum work is required in the field...Ideally, I would like it to fly itself; so that I can make a file (GPX or shapefile) that shows the exact location of the field/ground where the picture will need to be taken. My last concern is about the stability of the drone/uav and whether images taken with this uav would be clear enough to distinguish between stressed and non stressed crops. Field size I am looking to use it for is 100 acres. By writing my thoughts here, I am hoping that someone in this forum has done something similar and I would very much appreciate the advise...Otherwise, do you guys think I can custom make such a UAV... or does it require advanced skills...
Thanks and Happy New Year
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The Event38 founder, Jeff Taylor, has complete solutions for your goals, fixed or rotative wings.
Thank you ECODRONES for the help. I checked the website and learned about their modified cameras. The cameras offer IR but at the expanse of the RED. Unfortunately, I need the Red and the NIR spectral signatures for my research in order to calculate vegetation indices such as NDVI.
Would this place get you going? I'm hoping to do something similar...Bixler 1.1 on it's way!
In most cases, you can use blue channel to make NDVI maps.
(Red channel is not fundamental).
If you want the NIR and Red channel, you can take a look at maxmax http://www.maxmax.com/vegetation_stress_mkii.htm
Check this out. Highly recommend it http://publiclab.org/wiki/near-infrared-camera
Thank you for the link. The issue with the modification is you end up with no red signature in order to get the NIR. Most vegetation stress indices need the Red signature (i.e. NDVI = f (Red, NIR)). However, this is the option I am working on right now. I am trying to modify a canon and see what I will get.
Yes, I understand. I think these guys make post-processing in http://infragram.org/ . And yes, they modified the camera using these filters http://store.publiclab.org/products/infragram-diy-filter-pack
Processing also can be done with this http://flightriot.com/post-processing-software/fiji-imagej/
And yes, you need 2 cameras see https://github.com/nedhorning/PhotoMonitoringPlugin for details
One more thought. Since NDVI is defined as
NDVI= (R660nm-R810nm)/(R660nm+R810nm)one can do calibration of the single modified camera.
Yes, the red channel is used in a large number of formulas. The red channel is interesting to detect carotenoids (mean the end of life for the plant).
However, at certain stages of maturation it is possible to replace the red channel by the blue channel. The results are very close.
Indeed, it is a risk!
Thank you Essam
Thanks Eugene for the inputs. I am not sure I understood what you meant by calibration of single modified camera. However, I am planing on using one camera only; a modified NIR camera. Something equipped with a double blocking filter allowing Red, green and NIR. The problem with all these DIY sites is that they suggest you block the red channel in order to capture the NIR instead. Additionally, it seems that the NIR signal tends to register in the blue and green channels as well starting at 820nm. If no alternative, one can come up with a modified NDVI that included NIR, Blue and Green (no red). Anyway, post processing would be a must for these cameras and ideally you want to shoot in raw mode. I am still investigating looking for the best low budget camera for this job....