Experimenting with bullet-time software for Raspberry Pi cameras

Created using Xangle Camera Server: xangleCS.com
Related blog post & additional images: www.xanglecs.c...
We started to work on a PiCam version of our multi-camera software a few months ago, but that had nothing to do with our usual bullet-time work. It was mostly about photogrammetry, which should look like our DSLR system, with much smaller cameras. And that part is ready.
But as we had the equipment and the software I got interested to see how far we could push it with bullet-time and what kind of image quality I could get out of these tiny cameras. My main interest here is the size of them as they can be put super close to each other, giving me my best density ever on a multi-camera structure
Now just as with our Android or DSLR edition, this works with a dashboard to change the camera settings and output settings. We also have our usual instant playback player, our gallery, and tons of modules.
On the first iteration of the kit, I couldn't get a good calibration as the PiCam lenses are mounted on a thermal paste and can't be placed with precision. This is what I got from this first kit. It is quite shaky. The problem is that these are very wide lenses, and with the distortion, I really need to have all of the cameras to look at the same center spot. But as I got more hooked about the end results I was getting, we tried to see if we could get rid of that paste to stick the lenses directly to the small boards. It's not perfect, but it's getting close. This is my actual kit!
For all of my tests using continuous light, I'm using 15 PiCam on 15 Raspberry Pis 3b+ with no custom electronic components. Each Pi is sending its data through ethernet cables to the switches to the laptop. My trigger is a simple bluetooth powerpoint presenter. But for my shots using an external strobe, we had to design a little PCB to send the signal to my speedlite. The board is on the last pi, and linked to the flash via an audio cable and a hot shoe adapter. Any kind of flash can work for this.
The Picams board are mounted on laser cut acrylic plates which connect to an extruded aluminum bar via these 3d printed adapters. Each
I did this project as a cool experimentation, and this is never going to replace my DSLRs, but this is opening the door to different ways of using this technology, and yes, it is compatible with the new PiCam HQ, and that looks very promising. I'll play with that next week!
/ thexangle
/ ericparephoto

[@Ericpare]

Thanks all for your feedback! Here's the link to a similar project we did a year prior to this one using Android phones: kzbin.info/www/bejne/iKS2YoJte7qCapY

[@mjdegans]

Is your code for this on GitHub? How did you get synchronization right between all the Pis?

[@theguru143]

You have been super busy pushing the technology in new, exciting directions. I have plans with my light painting and am hoping to purchase the software for this sometime next year *fingers crossed* As always, thank you for the information and updates

[@eformance]

If you want to make the cheap cameras more consistent, mount the front of the camera through a hole cut in the plastic, then glue the housing to the plastic. If all of your mounts are the same, the focal plane of each sensor will be the same. AKA, front mount the camera instead of back mounting it.

[@MikeJamesMedia]

Great work, Eric. That obviously was a challenge, and it's getting better each time!

[@microcolonel]

I'd love to see what could be done with the current breed of small camera modules and capture options. Two, four, and even eight cameras at once on a single board is not unheard of, and would significantly improve the hassle for large photogrammetry setups. Another improvement would be to mount the camera modules from the sensor/lens, rather than the PCB.

[@2BeersInside]

Hi! nice project. I'm working on the similar project with HQ cameras. Do you have any results with your new setup with 4 HQ cameras ?

[@HermannSW]

With a 3$ v1 camera instead of v2 you can get "global external shutter" feature, allowing you to capture highspeed stuff without rolling shutter effect: github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter#introduction Some MIT students used that technique for "Matrix style" capturing of bullet inflight with 16 cameras: www.raspberrypi.org/forums/viewtopic.php?t=240442

[@BorisGrishenco]

Can you specify how are you triggering cameras?

[@MrFaaaaaaaaaaaaaaaaa]

if you sync the pis and stagger the timing of each picture aquisition you could get 15000FPS out of this rig* *at very low resolution when they were testing nuclear bombs they used a special device that had an array of cameras pointing at a spinning mirror. as the mirror rotated the view of the subject of the picture into view each camera in the array would be activated by the same mechanism that was rotating the mirror. What you've made here could do the same job with some image processing and accepting artifacts of distortion from camera offset without a mirror

[@tomy111089]

Amazing video!

[@FauxtakuLounge]

Fantastic.

[@arunalakmal9031]

Super Coooool....

[@joeykeys2003]

Is your software compatible with linking Gopro cameras as well?

[@Ericpare]

nope! Gopro is not providing anything to control their cameras accurately through cables

[@joeykeys2003]

@@Ericpare I appreciate the heads up. Thank you for all these amazing videos!

[@mjdegans]

Nice. Synchronization is hard.

[@MDMiller60]

I don't understand the result. What did/does it do?

[@JerryWilliam63]

Happy Kitty.

[@glglkuri]

This is interesting , how do you mount and align them?

[@Ericpare]

thanks! The mounting is explained in the video. The calibration is explained here: xangle.zendesk.com/hc/en-us/articles/360030572471

[@DeadlyMustard]

Impressive innovation! Love it!

[@Ericpare]

thanks :)

[@nacholara8419]

Hi Eric! I just discovered your channel and Im soo impresed right now, very hyped to watch all of your videos during those days. Since the 3D stereoscopic Nishika N800 effect became so popular on videoclips and professional video productions I have been obsesed on finding the way to make it with 4 or 6 cameras and same shutter in a easy and portable way. Keep working on your proyect and consider the possibility on make a small version of this! 🤘

[@Ericpare]

hey thanks! The last seconds of that video are a digital wink at the N800. We're working on it :)

[@Michaelmusset]

Hi great work ! Is it free for personal usage ? association ?

[@Ericpare]

I do have a couple of short-term licenses available in exchange of content. You can write your project proposal on this page: xangleapps.com/trial

[@fernandogomez3891]

Great work! One question... Use you any program of another people's projects or is it your own programming stuff?

[@iwetino]

are you able to do a setup tutorial or link any documents as I'd really like to replicate this with just four raspberry pi cameras? thanks for the cool vid

[@Ericpare]

it's going to take a few weeks, but we're working on it.

[@iwetino]

Eric Paré / Xangle can't wait! thanks for the response :))