Recently in Low elevation aerial photography (LEAP) Category

This post illustrates the use of a simple KAP rig in conjunction with structure from motion photogrammetry to generate a dense surface model of a threatened archaeological site.

Over at the PublicLaboratory, they have come up with a nice simple and inexpensive telemetry kit for balloon aerial photography (BAP). The information the unit collects should help with image georeferencing. I suspect that the data could potentially be exploited by applications like Palentier that was written by Mark Willis and M. Stange.

Research KAPers don't have the luxury of flying where the conditions are optimal. We work where the subjects are located and then we have to be creative about "making it work". Some locations just aren't suitable for KAP. In these cases, it is probably best to turn to BAP, PAP, or RC. However, understanding wind can really help the conditions under which a KAPer can be successful. Heritage documentation expert and KAPer extraordinaire Bill Blake has one of the best discussions of wind for KAP that I have seen thus far.

Archaeologist and elite low elevation aerial photographer Mark Willis recently posted a wonderful and informative tutorial on how to create a DEM from a Photosynth Point cloud. The photographs used in his tutorial example were captured by KAP, and the site is Palmitopamba in Ecuador. KAP is probably the most inexpensive LEAP technique, so this was a great proof of concept. Mark also strove to use free and open source applications through the entire work flow. Again, this low cost approach means that the methods should be available to nearly any researcher. One of the stages in Mark's procedures draws inspiration from an earlier post on this site regarding the transformation of structure from motion point clouds to real world coordinates. Mark simplified and clarified the process. This was exciting for me because it was Mark's earlier work with photosynth that stimulated my interests in KAP and structure from motion photogrammetry.

Over on Cris Benton's KAP Discussion Board, I recently ran into an article on applications of kite aerial photography (KAP) in archaeology on the Yucatan Peninsula by Oscar Frey that appeared in a Drachen Foundation publication entitled Discourse. I was particularly interested in cross-eyed stereo figures of the site of Dzibilchaltun that appeared on page 29 of Frey's article. The images seemed to illustrate well the architecture. Thus, I decided I would see if I had images in my archive that would be suitable for the method. Cross-eyed stereo images take some practice to view, but the method has the advantage that no special glasses are required and color is represented faithfully.

Thanks to kite historian Andrea Casalboni for directing me to this paper.

Maude, Keith (1985) "How to Rise Quickly in Field Archaeology" Popular Archaeology.

Two days ago, I discovered that MeshLab version 1.2.3a permits the selection and deletion of points in a point cloud! Sadly, the discovery came after I spent $800 on the commercial package VRMesh Studo. I purchased simply to delete points in a point cloud. It turns out that VRMesh studio performs several other tasks that are useful for dealing with SfM point clouds. Yet, still in terms of using SfM (Photosynth and Bundler) as a low-cost tool for 3D modeling this new development in MeshLab essentially solves what many of us recognized as the "missing link". I have downloaded and used MeshLab version 1.2.3a. It opens ASCII ply files produced by either Bundler or Photosynth (and saved with the synth point cloud export tool). I am pleased with the meshing results.

In hopes that the processing techniques would be of use to others, I provide an outline of my methods.

Frank Taylor, who runs the Google Earth Blog, has added some kite aerial photographs to Google Earth and Google Maps. Read more about it here. The work was done with the help of the good people at Grassroots Mapping. This work is another wonderful example of LEAP (low elevation aerial photography). Over at Benton's Notes on KAP, I started a thread on the Frank Taylor story.



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Balloon Based Geo-Referenced Digital Photo Technique

Many Low elevation aerial photography platforms are sensitive to wind conditions. In the case of KAP and fixed wing R/C, this is very much the case. Kites require wind to fly, and lite aircraft are blown about by strong currents. To help quantify flying conditions, I just picked up a Kestrel 4500 Blue Tooth weather meter, belt clip case, and portable vane mount. This should really help quantify wind conditions. Much like a geotagged photograph, I plan on time calibrating the instrument for use with GPS position logging.

This post illustrates low elevation aerial photographic (LEAP) equipment that I use and how this equipment is packed for portability and safety.

A HawkEye fixed wing aerial platform was obtained for use in aerial photographic mapping of large spaces.This aerial platform will permit the capture of photographs is low and no wind settings.The equipment compliments the existing KAP systems which are well suited for high wind settings.