Multi-camera setup project. - page 14 - Creative Uses of CHDK - CHDK Forum

Multi-camera setup project.

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Offline mphx

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Re: Multi-camera setup project.
« Reply #130 on: 21 / August / 2014, 18:15:20 »
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So, how do you know the syncing is 'very good'  ?  :)

as i have mentioned before ...the whole project is about taking shots people...and creating a 3d miniature out of it.
The whole process doesn't involve movement...of course we wont tell the people FREEZEEEE...we want them to act naturally the time of the shot..but of course not to move alot.
It's like when we get a photograph...u don't run around but u don't play "statue" either...

Considering all these things...test photos were rather synced...i mean all cameras shot almost at the same time.In other words , photos were OK for processing.

In some test shots i was moving my hand...the hand was foggy in the result photos...probably not a good thing...but as i said..the purpose of the project is not to take photos of "moving" objects....

Minor movement will exist of course but this will be handled later at 3d processing.Surely there won't be a hand up in one photo and a hand down in another..we are not talking about that large of movements..
Maybe a very small hand swinging...a minor cloth movement...a bit of a head shake...small movements...
We can handle these things :)

As a conclusion , syncing for the project requirements was "very good" :)

Re: Multi-camera setup project.
« Reply #131 on: 22 / August / 2014, 05:23:40 »
.
As a conclusion , syncing for the project requirements was "very good" :)

and if nothing moved at all, sync would be excellent.

In fact, you could just walk around the subject with a single camera and take as long as you like  :)

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Offline mphx

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Re: Multi-camera setup project.
« Reply #132 on: 22 / August / 2014, 14:56:58 »


and if nothing moved at all, sync would be excellent.

In fact, you could just walk around the subject with a single camera and take as long as you like  :)

true :) we have done it ....but that's not the point...

Many problems with the cameras...they do not operate as supposed.Probably something to do with cables and hubs.We are trying all possible ways....

We have 8 tripods...7 of them working as intended ALONE...if we hook them up all together...problems. the 8th tripod doesn't work at all...we have to change hub there to be sure.

As i see it , hubs generally suck. In one situation one tripod (8 cameras) had strange behavior...and when we change ports in the hub...all were working fine...go figure.....
Another situation , behavior was strange with 8 cameras..but fine with 6 or 7....

So i start to believe that hubs ( 10 port) don't behave well if you fill them up with devices...they are made with the belief that not all ports will be used at the same time...

Anyways , we continue our tests and try every possible solution until everything work fine :)

Re: Multi-camera setup project.
« Reply #133 on: 22 / August / 2014, 15:51:45 »
Although probably of little interest for your application, I will mention an alternative method of working.
I like simple methods, even at the 'cost' of mild inconvenience compared with 'sophisticated' solutions.
My rig consists of three tripods each with eight A620 cameras.
Each tripod has a connector for the +6V power and the USB trigger signal.
The battery voltage is fed directly to each group of eight cameras, no voltage converters are used.
The USB cable is thin two-core, not a proper USB cable.
I have tested the first group, it works perfectly as you would expect with such a straightforward configuration.

When all shooting is completed you can swivel each camera and either remove the SD card or insert a normal USB cable.
Using USB or card reader, the images are automatically downloaded to numbered folders and after the last camera is downloaded an external application is automatically launched.

That is sufficient for my requirements and possibly for some others.

Keep it simple .........


David


Re: Multi-camera setup project.
« Reply #134 on: 22 / August / 2014, 23:27:34 »
When all shooting is completed you can swivel each camera and either remove the SD card or insert a normal USB cable.
For 24 cameras ?  Really? Every time you want to transfer images?

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Keep it simple .........
If your cameras don't support simultaneous PTP and USB remote precision sync then I guess that's your only choice.
« Last Edit: 22 / August / 2014, 23:30:47 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Multi-camera setup project.
« Reply #135 on: 23 / August / 2014, 06:29:15 »
For 24 cameras ?  Really? Every time you want to transfer images?

Not a problem, takes very little time, you have to wait for the batch of images to download anyway.
Images renamed and routed to individual folders automatically so that is the great chore saver.

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If your cameras don't support simultaneous PTP and USB remote precision sync then I guess that's your only choice.

My personal build not only supports PTP and USB remote precision, there is also a very nice PTP client that I have previously mentioned in the forum.

However, as a matter of philosophy  I much prefer the simplest approach possible.
So do SDM users, that is why many KAP's have no interest in Lua ............. as they told you.

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Offline mphx

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Re: Multi-camera setup project.
« Reply #136 on: 23 / August / 2014, 12:43:30 »
Here again ,


Tests continue....lets see.

1. We managed to shoot with 56 cameras....that's the maximum we have achieved. Result is very good.That's promising.

2.Cameras don't have a steady behavior..from a number and up there are randomly malfunctioned cameras.
I don't know what to think.Hubs not good enough?Cables? usb controllers on the pc ?operating system can't handle more than a maximum number? We even bought a pci (usb) card for extra usb ports.Not much help.

Next step is to use linux to check if things will go better there.And we are thinking to buy more expensive usb hubs...
We need to establish the maximum number of cameras connected to a pc that can work flawlessly AT ALL TIMES ...


There were times were 7 tripods ( 56 cameras) were working flawlessly and there were times that 1 tripod , alone , was behaving bad....only one..for god sake...

I tend to believe it's all about the hubs and the cables...if that is the case..it will be easily solved...


P.S. : that PS is for reyalp :) I noticed that when i had X number of cameras working ok and doing stuff..deleting images from them (multicam command) was missing some cameras when trying to delete images.I had to issue the command twice to be sure that all images from all cameras were deleted.Cameras were still connected to the program (i could go from rec mode to preview mode and vice versa but delete command was misbehaving)

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Offline reyalp

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Re: Multi-camera setup project.
« Reply #137 on: 23 / August / 2014, 18:15:38 »
P.S. : that PS is for reyalp :) I noticed that when i had X number of cameras working ok and doing stuff..deleting images from them (multicam command) was missing some cameras when trying to delete images.I had to issue the command twice to be sure that all images from all cameras were deleted.Cameras were still connected to the program (i could go from rec mode to preview mode and vice versa but delete command was misbehaving)
This doesn't really give me much information to go on. I would expect failures to generate some warning messages in the console.

Regarding the issues with lots of cameras connected: If you are still using the GUI to control, I would strongly trying using the CLI. You could also try
set gui_dev_check_interval=0
in the GUI.
Don't forget what the H stands for.


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Offline mphx

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Re: Multi-camera setup project.
« Reply #138 on: 24 / August / 2014, 02:38:27 »

This doesn't really give me much information to go on. I would expect failures to generate some warning messages in the console.

Regarding the issues with lots of cameras connected: If you are still using the GUI to control, I would strongly trying using the CLI. You could also try
set gui_dev_check_interval=0
in the GUI.

Well , when multicam has "lost" some camera(s) , it pop ups a blank popup window with nothing on it.When i see this popup i know that a camera has lost connection.From this point no command can be issued so i have to reconnect them.
Same popup occurs when i "delete" images on cameras..although in this case no camera has lost connection.
Another "message" i see with "delete" command is (i will try to describe it since i don't quite remember it)..it displays in the console the actual command that is used and below that something like <id> : I/O error.
And starts deleting images...but i know it has missed some...so i have to issue it twice to get the rest.

Using CLI was my next thought.To check if behavior of multiple cameras are more steady or not.If random connection failures are because of gui or not.

I will try the command you suggest and see if things are any different when using gui. thanks.


PS : at some point of the tests... i had an error/message ...something like "cannot send <name of command> command : msg queue full. From that point nothing was working..i had to reboot ALL cameras.Any ideas about that?
« Last Edit: 24 / August / 2014, 02:40:22 by mphx »

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Offline reyalp

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Re: Multi-camera setup project.
« Reply #139 on: 24 / August / 2014, 15:47:24 »
Well , when multicam has "lost" some camera(s) , it pop ups a blank popup window with nothing on it.When i see this popup i know that a camera has lost connection.From this point no command can be issued so i have to reconnect them.
Did I mention you should try not using the GUI? ;)

The blank popup means there was an unhandled error somewhere. Unfortunately IUP default error handling doesn't play nicely throwing non-string errors, while chdkptp throws an "error object" table to provide finer grained error handling.

Most of the stock chkdptp code should catch any errors and give you a proper stack trace, but it's possible I've missed some places. If you are using custom GUI code that's just calling multicam functions from a button callback or something like that, it would also have this problem. Since you haven't published the code, I can't give you much help with that.

In general, if you have a callback that calls chdkptp functions, you can do something like
mybutton.action=errutil.warp(function()...end)
where the inner function is whatever your normal callback would be. That will cause errors to go to the console.

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Another "message" i see with "delete" command is (i will try to describe it since i don't quite remember it)..it displays in the console the actual command that is used and below that something like <id> : I/O error.
IO error means that some problem has happened with the USB connection. So this is probably due to your general USB stability problems, and not specific to delete.

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PS : at some point of the tests... i had an error/message ...something like "cannot send <name of command> command : msg queue full. From that point nothing was working..i had to reboot ALL cameras.Any ideas about that?
That should mean that the one (or more) of the cameras was not processing messages as fast as you were sending them. Without knowing more about the specific sequence of events, I would be very difficult for me to guess what is happening.

multicam commands are implemented as messages sent with chdkptp <connection>:write_msg. The camera side script (rlib code at the bottom of multicam.lua) sits in loop waiting for messages. The message system has a queue that can hold up to 15 messages. Normally, you should wait for the previous command to be processed before attempting a new one, by using cmdwait or a hard coded delay.
Don't forget what the H stands for.

 

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