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CHDK PTP multiple instances

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Offline reyalp

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Re: CHDK PTP multiple instances
« Reply #70 on: 08 / October / 2013, 23:34:24 »
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"Multi-Camera Synchronization...Enable Sync...This allows CHDK on several cameras to focus, adjust exposure, setup the flash and then wait for a shared signal to complete the shot"

was that allows equated to 'focus / exposure adjustment' automatically happening as part of that process. 
When you use the USB remote, the camera autofocus and autoexposure (or manual settings, or CHDK overrides) operate normally.

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I must soon buy a camera and start tinkering -
If you are serious about this, I'd suggest you get one as soon as possible. Even if it's not the model you use for the project, getting on the learning curve sooner will probably save you overall. You can get a bottom of the line or used powershot very cheaply compared to the cost of the project.
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but your current wifi investigations introduce a further interesting quandary into that decision  8) 
Wifi could nicely solve the issue of juggling USB remote and USB protocol connections. I would not expect high precision sync to be possible over wifi alone, although waiting for a single broadcast packet (not a PTP/IP command) could be conceivably be quite a bit better than PTP.
Don't forget what the H stands for.

Re: CHDK PTP multiple instances
« Reply #71 on: 09 / October / 2013, 03:20:13 »
Last reply is all good comment & advice reyalp - thanks.

In particular:

Wifi could nicely solve the issue of juggling USB remote and USB protocol connections. I would not expect high precision sync to be possible over wifi alone, although waiting for a single broadcast packet (not a PTP/IP command) could be conceivably be quite a bit better than PTP.

I hadn't thought tight synch would be possible over wifi - but even being able to revert to a gentles like remote switch instead of the previously proposed 'powered usb hub network with multiple associated arduino controlled optoisolators and FET switches ' thing would be very nice.

Who knows, if you get it all working nicely, the [wifi] 'broadcast single packet synch' may be good for most use cases of the photogrammetry application I have in mind.

Some folk, with familiarity of that app, currently use a turntable along with a single vertical 'pole' of multiple DSLR cameras to 'capture' living objects - and still get some reasonable results using a 10 second 'please stay still ' process. So a totally wireless solution [excepting power cables] and perhaps using continuous light sounds worthy of future consideration - in fact it may even get the application mobile and 'out of the studio' !

Maybe someday a 'whizkid' can dream up something [a little] like that temperature sensor hack [but that could be instantly applied to all cameras for remote synch] and then we really could have a truly 'wireless' precision synch system.

Maybe...maybe i'm getting ahead of myself !



**My note

consider using chdkptp to set 'settings' prior to chdkptp shoot() - rather than using 'on camera' chdk script:


I am using an Arduino that triggers all the cameras, the exposure parameters are read from the SD-Cards as setups. Now before trying to improve the synchronization of my cameras with the CHDK USB remote function, I would like to find out if it would be better to start from scratch, not using an Arduino any more but to connect all the cameras via USB to a single PC. That would be a great step forward for me, because at the moment I have to take out the cards from the camera, put them into a card reader, read the images and so on . Also I could adjust all exposure parameters from a single place, if I manage to connect all cameras to chdkptp and trigger them by the computer.

So I bought some USB-Hubs, at the moment I have stacked one Hub into another one that is connected to a notebook. The two SX200IS are connected at the end. I managed to switch between them using the method described here (!con=conX) and trigger the cameras one by one.

This is quite exciting for me, but now I wonder how to make the cameras shoot at once. Is there a way to bring the camera into a "ready-to-shoot"-mode, like the one I have when applying 5 Volt to the Y-cable I use together with CHDKs USB remote function. And then fire them all at once or with a very short delay?

Do you have any suggestions how to achieve a multi-camera-shooting with chdkptp?

I have also skills to build special gear for such a thing, I am able to program Arduinos and can solder relais together to maybe physically disconnect cameras from the Y-cable and connect them to the Hubs, or vice versa.

I appreciate any proposals very much! Thanks! Martin

« Last Edit: 09 / October / 2013, 05:19:32 by andrew.stephens.754365 »

Re: CHDK PTP multiple instances
« Reply #72 on: 09 / October / 2013, 05:20:01 »
Maybe someday a 'whizkid' can dream up something [a little] like that temperature sensor hack [but that could be instantly applied to all cameras for remote synch] and then we really could have a truly 'wireless' precision synch system.

There is no problem getting a synch of a fraction of a millisecond with dozens of cameras fired wirelessly.
You use a single receiver whose output is plugged into the jack socket of the gentLes switch.
That is what it is for, I designed it.
You also use the USB extenders that gentLes sells, again designed with this type of application in mind.

Insisting on remote access to the images only complicates the issue.


David

Re: CHDK PTP multiple instances
« Reply #73 on: 09 / October / 2013, 07:36:52 »
There is no problem getting a synch of a fraction of a millisecond with dozens of cameras fired wirelessly.
You use a single receiver whose output is plugged into the jack socket of the gentLes switch.
That is what it is for, I designed it.

Appreciate this David, I wasn't aware of that - will look at James's site a little later.

The totally wireless P&S 'precision synch' solution may be just around the corner.

[my development note: memory is that one of the gentles switches also had a studio flash contol output - look into]   

You also use the USB extenders that gentLes sells, again designed with this type of application in mind.

If wifi becomes available then [for a totally wireless solution], the trigger solution chosen must be [cost permitting] the first option you referred to. If cost is prohibitive then simple on/off switching of a powered usb hub network may be cheaper than the gentles extenders ?

[my development note: control of a single power switch to all usb hubs by arduino controller allows the control signal - to the arduino input pin - to originate from the dslr / studio flash controller 'Camera-Axe']   

If wifi does not become [useably] available then the gentles USB extender product is incompatible [for my purposes] since it does not enable simultaneous chdk usbremote & chdkptp operation

Insisting on remote access to the images only complicates the issue.

It does complicate the issue but [for my purposes] not unnecessarily so. For me an 'automated' production process [minimal manual intervention] is preferable.   


Re: CHDK PTP multiple instances
« Reply #74 on: 09 / October / 2013, 07:51:19 »
It does complicate the issue but [for my purposes] not unnecessarily so.

Can you describe your entire desired workflow from image-capture to final 'product' ?


David

Re: CHDK PTP multiple instances
« Reply #75 on: 09 / October / 2013, 09:32:43 »
Can you describe your entire desired workflow from image-capture to final 'product' ?

The long answer reply

I aspire to this http://ir-ltd.net/scanning-with-ir/ - but priniting 3D figurines. [Infinite Realities use over 100 DSLR's - a lot of money]:

I quote

"...IR can scan 100′s of expression scans in under an hour, dozens of t/a-pose full-body scan costume changes an hour, or 100′s of dynamic poses an hour.

The system is now designed to be 99.999% reliable, NO dropped frames, NO black images and super fast. It’s now very easy to capture high resolution, super detailed scans of humans in a split second. Processing takes time but most projects can be delivered in around 24-48hrs thanks to IR’s custom built render / processing farm built specifically for photo reconstruction."


For 3D printing [given current printer resolutions] I think multi P&S may be adequate [for body section at least]

Truth is I haven't yet purchased the photogrammetry application [or any cameras (P&S or DSLR)].

So, I think i'll take the plunge and
 
(i) purchase two [wireless enabled] P&S [IXUS 240 HS ? - pity SX280 not available for 60fps 4D investigation with your new synch cable !] and a single 10 port usb powered hub

using this i'll try and get the chdk / chdkptp side, largely, understood.

(ii) i'll then purchase

  • single EOS 100D
  • DSLR / Studio Flash Controller [http://www.cameraaxe.com/]
  • Arduino controller
  • serial to parallel latch chip (74HC595)
  • optoisolators
  • FET's
  • sundry components
  • studio flash
  • standard edition photogrammetry software 'Agisoft Photoscan' http://agisoft.ru/products

With this, i'll work out the DSLR / Studio Flash / P&S integration http://www.dreamingrobots.com/forums/viewtopic.php?f=8&t=44&start=10

I'll use this configuration to capture multiple sets of images of a 'tailors dummy' - feed the images into the photogrammetry app and [assuming all goes well] expand the system.

Perhaps an all P&S system will suffice.

Perhaps a mixed DSLR (head) / P&S (body) is required.

Perhaps i'll migrate to a complete DSLR system over time.

Perhaps Kinect 2 will make all of the above redundant.

So,

the short answer

Can you describe your entire desired workflow from image-capture to final 'product' ?

I don't think that I can [but it would probably be best to do that before step (i)  ::) ]

This is about as close as I have previously got to a workflow http://www.agisoft.ru/forum/index.php?topic=1559.msg8166#msg8166 - could try harder  :(
« Last Edit: 09 / October / 2013, 09:49:54 by andrew.stephens.754365 »

Re: CHDK PTP multiple instances
« Reply #76 on: 09 / October / 2013, 10:00:21 »
Well, all I can say is good luck, it is an ambitious project  :)

Re: CHDK PTP multiple instances
« Reply #77 on: 09 / October / 2013, 10:20:12 »
...it is an ambitious project  :)

I think so - with many novice mistakes and [silly ?] questions along the way. Please be patient with me  :-[


Re: CHDK PTP multiple instances
« Reply #78 on: 09 / October / 2013, 11:00:35 »
There is no problem getting a synch of a fraction of a millisecond with dozens of cameras fired wirelessly.
You use a single receiver whose output is plugged into the jack socket of the gentLes switch.
That is what it is for, I designed it.

Any chance you can post the links for both transmitter and receiver ?



Edit:

Is this it 'gentSTEREO-proSDM '

'Trigger input (3.5mm mono jack), allowing an external electrical pulse to be used to trigger the camera.'

referenced here http://www.gentles.ltd.uk/gentstereo/sdm.htm ?



I know some people on the 'Agisoft' forum who may, currently, be interested in that.
« Last Edit: 09 / October / 2013, 13:32:36 by andrew.stephens.754365 »

Re: CHDK PTP multiple instances
« Reply #79 on: 10 / October / 2013, 16:17:20 »
Looking over some older, related, posts - this one has confused me:

http://chdk.setepontos.com/index.php?topic=9420.msg96751#msg96751

is that possible to use usb connection both for to the simultaneous sync shuter realice and file transferring to my pc from all my cameras at the same time?
Sort of.  If you use chdkptp and a little scripting on its command line you can transfer files from multiple cameras and you can cause them to shoot. 

However, you won't get precision sync that way - you need to use the CHDK/SDM built-in precision sync function and a mechanical switch that controls the +5V USB line for that.  You can build something farily easily if you want - insert a switch in series with the red wire of a standard camera-to-computer USB cable and use the PC for your +5V power source.  Leave the switch in the ON position when transferring files.  I do this all the time.

Help:

Does this infer that chdk usbremote and chdkptp were already in co-existence ?

If so, what does kbd.c change in this thread:

physw_status[USB_IDX] = physw_status[USB_IDX] | USB_MASK ;  // NEW : make it look like 5V is there no matter what

at http://chdk.setepontos.com/index.php?topic=8769.msg105488#msg105488 achieve in addition ?

 

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