In Polly Cove, just outside of West Dover, Nova Scotia there is a granite boulder with a petroglyph carving of a pattern similar to a Celtic swirl. The carving is located near the top of the hill to the left of the old foundation.
I thought it would be interesting to make a 3D reconstruction of the petroglyph carving using image analysis software. The software works by comparing parallax (change in viewpoint) from a series of images and generates a series of 3D points. In order to use the Bundler SfM photogrammetry software I took a series of 10 photos of the double spiral pattern. To improve the accuracy of the experiment I used a slide bar to shift the camera by 1 centimeter for each photo.
There is a double spiral petroglyph on a granite boulder in Polly Cove.
The petroglyph is located near the top of the rock.
Autodesk Maya 2013 now includes a new 2D / 3D fractal system that can create fun and exciting fractal shapes like a mandelbox or mandelbulb right in your Maya viewport. The system works by using a Maya fluid effects "fluid container" to support rendering the fractal voxels with either a volume render or a hard surface render. You can also create fractal textures in the Hypershade.
Maya 2013 allows you to create complex fractal shapes using a fluid container.
Meshlab is a great program for loading and editing XYZ point cloud data and creating polygon meshes. It also does a good job as a 3D file format converter.
After you start using Meshlab for a while you will typically use the same filter settings over and over again for every project. Meshlab allows you to automate your workflow by creating your own Meshlab .MLX filter scripts. These filter scripts are in XML format and can be run from the Meshlab GUI or from the command line version of Meshlab called meshlabserver.
I discovered Meshlab when I started processing aerial images with Bundler / PMVS and needed an opensource program to edit Stanford Triangle Format .PLY files. Each time I ran a set of aerial images through Bundler I wanted to create a new polygon mesh from the ASCII PLY file. It can become tedious after a while applying the same Meshlab filters over and over again so I started exploring the world of Meshlab MLX filter scripts.
This blog post is probably one of the most hyperniche topics I have written about. If you are using Meshlab, or Meshlabserver along with SFM programs like Bundler I would really like to hear from you about your projects and experiences.
Here is a 1km long aerial mosaic image of Poly Cove in West Dover, Nova Scotia.
This morning I created a large aerial mosaic image of Polly Cove, West Dover, Nova Scotia. The mosaic image was stitched in Microsoft ICE from 25 aerial photos taken on Feb 14, 2012. The mosaic image covers a 1 km distance from Highway 333 to the islands off Polly Cove.
The photos were shot with an EasyStar Model airplane using a Canon PowerShot SD780IS camera and CHDK. I used the CHDK countdown intervalometer script to trigger the photos every 2 seconds with a 1/1500 sec shutter speed override.
I started in Microsoft ICE by creating a few smaller mosaic images using the Planar Motion 1 stitch mode and then merged the smaller mosaic's together in a final stitching pass. The full resolution version of the mosaic was 22,114 x 10,549 pixels (233 megapixels).
You can download a scaled down 3.5 megabyte 8Kx4K version of the mosaic image here: super_polly_cove_mosaic.jpg (Right click on the link and select Save Link As...)
Here is a stitched mosaic in Microsoft ICE from 9 photos.
The easiest way to stitch the big aerial photo mosaic was by merging together 7 smaller mosaics.
This weekend I started exploring aerial photogrammetry using Bundler and Meshlab. The first few Google searches I did while researching aerial photogrammetry discussed KAP (Kite Aerial Photography) enthusiasts who have used free photogrammetry tools like Microsoft PhotoSynth and Synth Export or the open source program Bundler (SfM) to create surveys of archeological sites.
My goal was to use aerial photos my brother & I captured with our EasyStar model airplane to create DEMs (digital elevation models) of our local scenery. The aerial photos I used to test Bundler were taken at a 400 foot altitude with a model airplane flying at 35 kilometers per hour. I used a Canon Powershot SD780IS camera with CHDK and the countdown intervalometer script to trigger the photos.
After a few hours of tinkering with software, reading manuals, and google searching I successfully created and textured my first DEM (digital elevation model).
This is a screenshot in Autodesk Maya of the first photogrammetry model I created using Bundler, and Meshlab.
Sample Bundler Aerial Images
A set of three vertical aerial photos taken with an EasyStar
I have included a ZIP archive with the three aerial photos from this tutorial. You can use these images to follow along with your copy of the Bundler photogrammetry software.
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