Deon van der Merwe
  • Male
  • Manhattan, KS
  • United States
Share

Deon van der Merwe's Friends

  • Renier van Rensburg
  • Benjamin Meltzer
  • Christopher Auger-Dominguez
  • Marino Ramirez
  • Serpentaire
  • Grant Oswald
  • Daniel Melia
  • LanMark
  • ECODRONES
  • bcrow
  • Michael Johnston
  • dudz
  • Patric Millar
  • James
  • John Stuart

Deon van der Merwe's Groups

 

Deon van der Merwe's Page

Latest Activity

Deon van der Merwe commented on Greg Crutsinger's blog post King Clone: Mapping ancient desert shrubs using Parrot Sequoia
"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…"
Aug 3, 2016
Deon van der Merwe left a comment for Renier van Rensburg
"Renier, ek sal graag met jou gesels oor landbou kartering. My direkte email is dmerwe2@gmail.com"
Jul 27, 2016
Deon van der Merwe replied to Todd's discussion New GoPro Lens vs Cannon CHDK for mapping in the group IRIS
"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…"
Feb 20, 2016
Deon van der Merwe replied to Pat Randall's discussion Business Opportunites for Drones in Agriculture in the group Agricultural UAVs
"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…"
Jan 3, 2016
Deon van der Merwe replied to Matt Gunn's discussion Let's talk Canon cameras
"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."
Jan 1, 2016
Deon van der Merwe replied to Byron Will-Noel's discussion Canon SX260 vs GoPro with Flat Lense & NDVI
"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. A potential…"
Apr 7, 2015
Deon van der Merwe replied to zk876's discussion Experimenting with NDVI , fiji + photoscan in the group Agricultural UAVs
"The effect you are seeing is likely due to bidirectional reflectance artifacts."
Feb 18, 2015
Deon van der Merwe replied to zk876's discussion Experimenting with NDVI , fiji + photoscan in the group Agricultural UAVs
"I will be happy to take a crack at processing your images if you'd like, but the Dropbox link does not appear to be working anymore."
Feb 18, 2015
Deon van der Merwe left a comment for Marino Ramirez
"Hi Marino, good luck with your Zephyr XL. The default parameter values are good to start with, but I have found that I need to increase the pitch P parameter a bit on my Zephyrs. Deon"
Dec 31, 2014
Deon van der Merwe replied to Benjamin Meltzer's discussion NDVI NGB Modified Camera Configuration in the group Agricultural UAVs
"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…"
Dec 11, 2014
Deon van der Merwe replied to Benjamin Meltzer's discussion NDVI NGB Modified Camera Configuration in the group Agricultural UAVs
"Benji, 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…"
Dec 11, 2014
Deon van der Merwe replied to Benjamin Meltzer's discussion NIR Camera vs RGB Camera Conversion in the group Agricultural UAVs
"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…"
Oct 26, 2014
Deon van der Merwe replied to Phil Ellerbroek's discussion New Exclusive 70" 2.0 Density Foam Flying Wing by RoboFlight in the group Agricultural UAVs
"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…"
Aug 27, 2014
Deon van der Merwe replied to Phil Ellerbroek's discussion New Exclusive 70" 2.0 Density Foam Flying Wing by RoboFlight in the group Agricultural UAVs
"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…"
Aug 27, 2014
Deon van der Merwe commented on Chris Anderson's blog post FAA vs Search-and-Rescue drones
"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…"
Apr 12, 2014
Deon van der Merwe replied to Kim Faber's discussion What software are people using to stitch photos together? in the group Agricultural UAVs
"The macros from MaxMax are scripts that plug into a free software called ImageJ. It is very limited, and takes a LOOOOOOOOOONG time to process images."
Mar 6, 2014

Profile Information

About Me:
Kansas State University
Please tell us a bit about your UAV interest
Agricultural applications
Hometown:
Manhattan

Deon van der Merwe's Videos

  • Add Videos
  • View All

Comment Wall (7 comments)

At 8:42am on February 11, 2013, LanMark said…

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.

At 6:07pm on February 11, 2013, Deon van der Merwe said…
Mark,

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.
At 11:19am on August 1, 2013, Serpentaire said…

Hey Merf, Saw this article posted referencing K-State...

http://diydrones.com/profiles/blogs/commercial-ag-goes-unmanned-auvsi-mission-critical-publication

Is this your team? 

At 11:29am on August 1, 2013, Deon van der Merwe said…

MegaFlare:

Yes, those are the people I work with at KSU. Kevin Price, Mark Blanks, Kirk Demuth, and several graduate students are involved.

Deon

At 12:01pm on August 1, 2013, LanMark said…

the images in that PDF weren't very high quality so I pulled one Carter (I believe) took of you and Kevin. :)

At 12:15pm on August 1, 2013, Serpentaire said…

Baie Geluk Merf....

Wonderful stuff and such great exposure.  I look forward to seeing the results of the study mentioned in the article. 

At 10:29am on October 28, 2013, John Stuart said…

Hey Deon

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.

Groete

You need to be a member of DIY Drones to add comments!

Join DIY Drones

 
 
 

© 2017   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service