An occasional blog where you can find my big thoughts and little ideas. If you’d like to hear more from me I post more frequently on mastodon: @Rob_Russell@mastodon.cloud.
Recently written
Gamma Camera
tl;dr: Gamma Camera is my open source flexible camera array project and you can build your own with https://github.com/robrussell/gamma.
I made a thing I call Gamma Camera. What is it? It’s easiest to explain starting from my motivation. For the past few years I’ve been tinkering with a lot of commodity camera parts and single board computers like the Raspberry Pi and Jetson Nano. I’ve also spent a lot of time trying to get a better handle on algorithms like structure from motion (SfM) and, more recently, neural radiance fields (NeRFs).
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Reordering frames, extracting I-frames, and other ffmpeg tricks
There are a bunch of ffmpeg commands I find myself copying and pasting over and over. Maybe you do too. Here are mine.
I’ll explain the flags for this first one in a lot of detail, if I skip a flag on another example then it’s probably described here. And I’ll link to some more thorough docs at the end.
ffmpeg -i /mnt/nas/photos/PXL_20230128_171859165.mp4 -vf select='between(t\,200\,210)*eq(pict_type\,I)*gt(pts-prev_pts\,0.500)' -vsync 0 -frames:v 100 /mnt/nas/frames-PXL_20230128_171859165/img-%03d.jpg Flags
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Rpi Camv3 Oqt Connector
Here’s another camera mounting block to 3d print. This part is meant to go with my previous design for mounting a Raspberry Pi on a t-slot rig. It’s just the minimum bit of plastic needed to join the camera module v3 to a 1/4-20" nut. Then the nut can be used to attach the camera module to a ball head like this one from Small Rig. Just like the rest of Gamma Camera the idea is to use 3d printed parts to bridge between common COTS parts.
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T-Slot bracket for a Raspberry Pi
My t-slot obsession has not let up. Last night I made a nice little design to easily secure a Raspberry Pi to a piece of 2020-profile extruded aluminum. This follows on from the 1/4"-20 to t-slot mount that I made recently. Just like that component, I used BOSL2 in OpenSCAD to quickly put it all together.
Design Here’s the design for the part if you want to have a look.
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