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Multi-camera setup project.

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Offline reyalp

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Re: Multi-camera setup project.
« Reply #40 on: 12 / July / 2014, 19:46:10 »
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commands that could read the contents of a file with the structure <serial number>=<number> in each line and compare a given string to the first part of every line (that is the serial number part) and take the number as a result and do something with it.
I assume it would be *rather* easy to be done with lua commands...
Yes, that has been my plan for multicam.lua. You can make a table indexed by serial number, and then you can associate whatever information you want with the serial.

For initial identification, you'd just need something like waterwingz number display (Or do something obvious with the display and/or AF led) and a command to record some id for the cam.  You could power them on one by one in order, or just connect to them all and go through the list. If you moved them around, you'd just need to update the affected cams.

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@reyalp

First of all testshots didn't work for me last time i checked..program unresponsive and had to force close it.
Don't know if it will behave the same with the latest version i compiled for future tests.
This should be fixed in rev 602. This happened if the synctime given was too short (which could also happen if you didn't specify one)

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I got all 8 cameras here , had only 2 for testing while partner had the rest..so i will try some syncing and shooting and see what will happen.

If you feel like to implement the thing about issuing sync timings through some file...let me know :)
I'll try to look into it, but I can't promise any particular timeframe. If you verify that the new method gives you acceptable results, I'd at least know it had the potential to be useful.

How are you measuring the sync?
Don't forget what the H stands for.

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Offline mphx

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Re: Multi-camera setup project.
« Reply #41 on: 12 / July / 2014, 20:22:23 »
@reyalp

At first phase , personally , i don't need to know what camera is what number.At shooting phase i just need photos to have some numbering so they can go all in the same folder without the risk of having two or more photos with the same name.

At second phase , for troubleshooting purposes , if some camera had some issues , yes , i would like a way to identify physically which camera is the problematic one.
At this phase numbering can be associated with serial number..so if i see that camera1 lets say didn't shoot and i want to find that camera on the poles...it would be nice to issue a command and pop a TEXT on the screen of that camera.
Sounds easy, but you know better :)
If you move them around , you don't care if the order of the numbers is screwed.You know you can find the camera you want issuing some command.
Worst thing is to do some unnecessary walking..big deal.

How i measure sync?Probably with some lame way , since i don't have any crt monitor lying around for some reliable measurements.
Last time i used an online meter ( this one http://stopwatch.onlineclock.net/ ) and tried to focus all cameras on it.Then checked pictures to see what sync was achieved.

Just finished installing CHDK to the cameras..trying to find a way to set them up all focusing at the same spot and will put a tablet there running the online timer.Tomorrow will do some tests , getting late.


Well , project will be done.We expect to be ready around September , too much to be done with the place , decoration , putting things , painting walls , construct the poles , buying stuff.
I just need to clarify from now which method will be used , because it will determine and some stuff that will be needed to be bought depending on that.
So take your time and do whatever you plan to do in your own pace...it will be useful at some point , since i see the switch-method is going to be rather troublesome so i intend to give chdkptp a GOOD TRY :)
« Last Edit: 12 / July / 2014, 20:23:59 by mphx »

Re: Multi-camera setup project.
« Reply #42 on: 12 / July / 2014, 20:38:36 »
I was reading novsela thread and i see that he is trying something similar with my project,although i believe our cameras wont be on the same level..but anyways.
I was seeing there some very complicated diagrams about the connections of the hubs etc.

I was thinking to use like 8x 10port usb hubs (8 cameras on each of them) and plug them all in 1x 10port usb hub connected to the pc.
A switch on that "last" hub and play with usb-remote and switch on/off method.I know its a very simple concept and i am missing something.

I am guessing it wont work as i imagine right?

Some Important Multi-Camera Project Design Points:-

For "Passive" USB-2 cables:-
* USB-2 Cable Length Limit of 5 meters.
* USB-2 Limit of 3(?) Hubs in Series.
* USB-2_7_Port_Hubs "ARE" two 4 port USB-2_Hubs but just connected in series.
* USB-2_10_Port_Hubs "ARE" ten independent ports.
* USB-2_10_Port_Hubs can have a 3 to 1 price variation for the same but re-branded product.
* USB-2_10_Port_Hubs have a, current limited, power supply delivered from the upstream PC.
* USB-2_10_Port_Hubs Switched , UnSwitched, Powered or Un-Powered are vey easy to "Hack".

For "Active" USB-1/2 over Cat5 or Cat6 cables.
* USB-1 Cable or Cat5 or Cat6 Cable Length Limit of 100 meters.
* USB-1/2 Cable or Cat5 or Cat6 Cable  Length Limit of 50 meters.
* A "Pair" "Active" USB-1/2 Adaptors always are required.
* The "Active" Adaptors for Cat5 or Cat6 cables always uses USB-1/2 protocols.
* All the Cat5 or Cat6 cables pairs are used, BUT they can be "Hacked" [the Details are a WIP]
* The  "Hacked #1" "Active" USB-1/2(s) will then have "Dual" USB-1/2 Channels.
* The  "Hacked #2" "Active" USB-1/2(s) can then have a "PoE" adaptor to:-

#1 Multiplex Dual Channel USB 1/2 "Read/Download" over a single Cat5 or Cat6 cable.

#2 Provide"PoE" battery "Trickle" charging for the multi-cam rig.
#2 Multiplex "Write/Shoot" over a single Cat5 or Cat6 cables via a "PoE" Adapter.

All the above seems very complex, but the "Hacks" and "Wiring" are all done in Break Out Box's. ["BoB's"]
So the the Multi-Camera Project with "BoB's" setup is very modular and is very easy to update or reconfigure.

Important Note in regard to "Multi" which in this post means 80 Cameras.
All, power mains supplied, Camera Battery Adapters have the ability to crate High ESD Voltages.
Also with 80 Camera Battery Adapters there could be 80 TIMES the Common Mode Noise
currents in the camera array rig.

With only a small number of camera in the project this will not be a problem....."BUT ....  is continued"

from here http://chdk.setepontos.com/index.php?topic=11583.msg113619#msg113619

and here http://chdk.setepontos.com/index.php?topic=11583.msg113516#msg113516

The Original Design Points are here http://chdk.setepontos.com/index.php?topic=11583.msg113423#msg113423
H-H

Edits #1 & 2 added some more design more details.

continued here http://chdk.setepontos.com/index.php?topic=11667.msg114430#msg114430

Edit #3  Another Important Design Point is also in regard to common mode "Noise Pick-Up":-

A 80 camera multi-camera rig will act as an large "Aerial" and pickup unwanted  AF and RF noise,
measured in "volts per meter".
The effective "Electrical Lentgh" for the rig will be many times, i.e. probably much greater than 100x, more that of a simple prototype rig.

For more details see http://whatis.techtarget.com/definition/volt-per-meter-V-m
« Last Edit: 13 / July / 2014, 04:24:31 by Hardware_Hacker »

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Offline reyalp

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Re: Multi-camera setup project.
« Reply #43 on: 12 / July / 2014, 20:40:22 »
How i measure sync?Probably with some lame way , since i don't have any crt monitor lying around for some reliable measurements.
Last time i used an online meter ( this one http://stopwatch.onlineclock.net/ ) and tried to focus all cameras on it.Then checked pictures to see what sync was achieved.
This will not give you a very precise measurement, for the reasons described in http://chdk.setepontos.com/index.php?topic=11583.msg114389#msg114389

This may be OK for your project, but you should be aware of it. The absolute best you could get with multicam will have something like 10-20ms variation anyway, and in practice it's probably worse.

You also need to make sure the exposure time is relatively short compared to the precision you are trying to measure.
Don't forget what the H stands for.


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Offline mphx

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Re: Multi-camera setup project.
« Reply #44 on: 12 / July / 2014, 20:53:55 »
@Hardware_Hacker

Thanx for your input on the matter , will keep them in mind.

@reyalp

I know its a lame way but it's the best one i can come with since i dont own a crt monitor anymore.

As i said before project is to shoot people standing on a platform in the center of the poles.I suppose exposing of the "objects" wont be that long and variation of the sync around some tens of milliseconds would be acceptable.
Differences in the photos will be "fixed" at the 3d modelling/processing afterwards.No big deal.
So if multicam at its best gives variations of 10-20ms or even 40-50ms..its acceptable.

Gonna do some lame tests tomorrow with the 8 cameras to see what's going on :)

Re: Multi-camera setup project.
« Reply #45 on: 12 / July / 2014, 22:13:55 »
@Hardware_Hacker
Thanx for your input on the matter , will keep them in mind.
@reyalp
I know its a lame way but it's the best one i can come with since i dont own a crt monitor anymore.

See post #42, edit #1

 I am working on a, low cost, simple, multiple 8x8 LED Dot Matrix Array Sync Tester using a
32khz watch crystal ["PAL" crt monitors have a horizontal frequency of ~~15.750 kHz.]

The concept is similar to Slow Scan TV but "ONLY ONE" LED in "X" x "Y" LED Dot Matrix Array is on at a time.
The, 16x32, or 16x40,  LED Dot Matrix Array can then have various scan times. i.e. 1x, 2x, 4x, 8x, etc.

The Slow Scan LED Array is "Reset" by the shoot command, the camera test images will be simple
"Bar Graphs" in Hexadecimal time. this can also record the time in S:M:H. see also here.

Black Standard_ free Windows Binary Clock http://www.romanblack.com/binclk.htm

Note:- The key concept is the camera "Sync" time difference and the fact that is measured in
            hexadecimal time units is not of any real practical significance.

H-H

Comments, Ideas, W-W, or any one.

Edit #1 a similar idea By ahull Re: testing sync among more cameras Reply #98 20/November/2013, is here

http://chdk.setepontos.com/index.php?topic=8312.msg107331#msg107331

This concept can also be extended to produce "Strip" Panoramas.
A camera is mounted on a old VCR "Video_Drum" motor the above timer outputs are used
to drive some sort of motor controller to rotate the camera.

A combined Multi-Camera Sync_Tester and a "Strip" Panorama maker.

Here http://chdk.setepontos.com/index.php?action=dlattach;topic=11667.0;attach=10443
« Last Edit: 13 / July / 2014, 05:18:57 by Hardware_Hacker »

Re: Multi-camera setup project.
« Reply #46 on: 12 / July / 2014, 22:41:32 »
I am working on a, low cost, simple, multiple 8x8 LED Dot Matrix Array Sync Tester using a
32khz watch crystal ["PAL" crt monitors have a horizontal frequency of ~~15.750 kHz.]
The concept is similar to Slow Scan TV but "ONLY ONE" LED in 8x8 LED Dot Matrix Array is on at a time.
The, 16x32, or 16x40,  LED Dot Matrix Array can then have various scan times. i.e. 1x, 2x, 4x, 8x, etc.
The Slow Scan LED Array will is "Reset" by the shoot command, the camera test images will be simple
"Bar Graphs" in Hexadecimal time. this can also record the S:M:H see also here.
That's kind of what I did here :  http://chdk.setepontos.com/index.php?topic=8312.msg104805#msg104805

I eventually modified what you see in the picture to use 10 "high bright" LED's.   With some fiddling with the initial count delay, I got quite good results.

But then I realized how much easier, and more accurate, this is if you use an oscilloscope.  Even the cheapest old analog one will do.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Multi-camera setup project.
« Reply #47 on: 12 / July / 2014, 23:19:56 »
"..... Even the cheapest old analog one will do...."

But everything is "Digital" these days, I traded my Old Analogue Junk for a "Free" Ixus 265 camera.

H-H

Slightly Off Topic, A combined Multi-Camera Sync_Tester and a "Strip" Panorama maker.

Example see the attached Hand Held Strip Pano-307 [low light].png

Was made on a hand held Ixus 125 using the continuous canon shoot mode.

Its based on the original concept By Knuckx CHDK Remote-2 - a two stage remote control adapter for CHDK

24/February/2012 here http://chdk.setepontos.com/index.php?topic=7717.msg81804#msg81804

and here https://dl.dropboxusercontent.com/u/39043879/IMG_0138.JPG

It could also be used or extended for a portable Multi-Camera rig.
« Last Edit: 13 / July / 2014, 01:28:10 by Hardware_Hacker »


Re: Multi-camera setup project.
« Reply #48 on: 12 / July / 2014, 23:29:46 »
But everything is "Digital" these days, I traded my Old Analogue Junk for a "Free" Ixus 265 camera.
Offer them a case of beer or the equivalent in local currency to trade back?
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline mphx

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Re: Multi-camera setup project.
« Reply #49 on: 13 / July / 2014, 06:07:02 »
Did some testings today with all 8 of them.

Since i don't own any fancy equipment for the sync testing , i just held a tablet running the online meter in front of the cameras.

On all 3 tests , all cameras "shot" the same time up to the last millisecond..That's a good thing although i get that this kind of measurement isn't that accurate.

@reyalp

At syncing process , i noticed that the program went unresponsive for few secs at the middle of the process.
That happened to me before when i was testing 8 cameras , but after some syncing , then it went smoothly.
Today i hit 2-3 syncs just to see the behavior , but on all syncs , the "problem" remained.
No impact to the shooting as i see , since all cameras were mostly synced.
I thought to mention it in case that indicates some problem...

 

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