Month: October 2018
Let’s make a 3D rendering of a forest!
Let’s do it with a video shot from a GoPro by someone walking around a camp site!
I’m not actually sure this is all that easy, or even possible. The main way to do this sort of rendering from a monocular camera is structure from motion (SfM), which relies on SIFT features in the image, and from what I recall of SIFT features, I’m not 100% convinced that they’re going to track very well from frame to frame, because the frames are mostly full of trees, and leaves look a lot like each other. On the other hand, there’s plenty of texture in the image, so maybe it will work just fine.
I’m planning to use Visual SfM, for which there are instructions online. Those instructions are for Ubuntu 12.04, but I’m on 16.04, so there are some modifications required. I got and ran the latest CUDA installer, using the local install rather than the network one because NVidia broke the network one somehow. I suspect a bad URL in the step where you install the keys.
I got what I think are the dependencies with the command
sudo apt-get install libgtk2.0-dev glew-utils libdevil-dev libboost-all-dev libatlas-cpp-0.6-dev libatlas-dev imagemagick libatlas
The build for VSfM was so quick I thought something had gone wrong, but it did build.
The SiftGPU link in the instructions is dead, but this looks legit. The make process threw some warnings at me, but no errors.
Rather than copying the library once it’s built, I linked it with ln -s ../../SiftGPU/bin/libsiftgpu.so ./libsiftgpu.so, we’ll see if this comes back to haunt me later.
I got PBA from the suggested place, and made it without adding the include for stdlib.h, since it’s 1.05 rather than 1.04 now, and perhaps they fixed that. It seems good, as it built (although with some warnings).
I went ahead and applied the mylapack hack to pvms-2, it seems to have gone well.
mv mylapack.o mylapack.o.bak
mv mylapack.o.bak mylapack.o
Graclus 1.2 built just fine (again with the warnings, though). Read the readme, it has how to set the number of bits used, and if you’re not on a laughably ancient machine, the value you want is 64.
I installed the cmvs from here, you want the one called cmvs-fix2.tar.gz, because non-fix versions seem to have issues with finding lapack.
After that I had to reboot, because everything that built was linked against CUDA and video drivers that I wasn’t running, and so it all crashed when it tried to render anything in X. After rebooting, everything came up fine and I can run VisualSFM, so the next part of this will be getting the video out of the GoPro and feeding it to VisualSFM.