"Greg, thanks for sharing these results. Very interesting indeed!
Another application of your data that could be interesting is to examine the spatial distribution of creosote plants. Based on a calculation of average distance between individuals…"
"I also use a Sony RX100 without gimbal on the Iris+ (I use a Canon s100 in the same way). I made a simple interface plate out of thin plywood that allows the camera to be mounted with the top facing forward. The interface plate is attached with…"
"Having been in the field for a few years now my perspective has changed somewhat. Many folks, including myself, over-estimated the rate of adoption by farmers. I think it can be attributed to a belief that aerial imagery would be a clear benefit in…"
"We are now using the Sony a5100 for most projects (RGB and NDVI). It has a 24MP sensor with excellent dynamic range. It is also light weight and small enough for easy installation when used with the Sony 16mm or 20mm E-mount lenses."
"I've had several MaxMax-converted cameras. Never had a problem, so I'm surprised to hear about Michal's issue, but they are pricey.
Event38 has a filter that is not quite equivalent to the MaxMax filters, but still useful.
"It is possible to use two cameras. We started with that method. However, it is a challenge to obtain precise synchronization between the cameras, it makes data processing more difficult, and it is not a complete solution in terms of band…"
You are seeing some of the complexities associated with using converted "NDVI" cameras. It does not make the data useless, but you have to take the limitations into consideration. One of the important factors to realize is that the…"
"It was unclear from the way you asked the question whether or not you were aware that you need a visible AND a NIR band to calculate NDVI. Having both on one sensor makes image processing much easier. Be careful of "IR" conversions that…"
"My first attempts at laminating bubbled as well. The trick is to prepare the surface with something that the laminate adheres to well. There are a couple of options.
I'm looking forward to seeing what you have on the way. Best…"
"The RF70 is superb. I want one please. Well done to you guys at RoboFlight!
However, dishing the Z3 is not necessary. I think both are excellent platforms if used appropriately. The Z3 sure is a nice hobby/FPV plane, but it is definitely…"
"Something that I fail to comprehend (maybe because it is incomprehensible), is why the FAA is concerned about commercial vs recreational use of model aircraft, when the FAAs reason for existence is to keep the NAS safe. Getting paid for a flight…"
Hi Merf.. I am in Iowa and AG research and analysis is a very interesting area for me. I am exploring some commercial service areas such as the vegetation stress analysis, especially once the FAA allows it.. before then my goal is to explore different areas of aerial inspection and photography. I don't envision this replacing my chief software architecture day job but I enjoy flying and using my software dev skills for AG research is a interesting cross over.
One thing I am trying to figure out is how to geo reference photos that you stitch together of a crop or anything.. so you can specify the lat/long of any given point in the stitched photo.
We use different methods depending on the level of precision and accuracy we need. Sometimes finding points in Google Earth can be good enough, such as road junctions, a recognizable rock, a tree etc. In most applications relative accuracy is more important than absolute accuracy, so you can often get useful data even if your georeferencing is not absolutely spot on. When we need a high level of precision and accuracy we place georeferenced markers made of vinyl window blind panels on the ground. The panels are white and 2" wide. You can form symbols with the panels to identify specific markers. It helps a lot in large fields of crops, where you may not have any recognizable features to differentiate images.
Believe me, South Africa misses you too, we have lost too many experts like you for our own good!
I am only at the scoping stage with my project, and the main test of its viability is whether I can generate reliable and useful NDVIs for some local farmers. I'm working with a hotshot organic wine farmer, who will help me refine the interpretation of the data.
At the moment I'm using several camera setups, some self-modified ones and some dual camera setups. From reading your material and emailing Mark Lanning, I may just end up going with the S100 and AgPixel solution, given that the calibration work has already been done. I'm also working on a way to normalize images from different days/atmospheric conditions for more inter-period comparability. Will post results if I get success.
I'm not an agronomist or photogrammetrist, I'm actually an economist trying to draw in the various threads and help with enhancing agricultural production efficiency and hopefully improve our food security situation going forward.
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