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Multi-camera setup project.

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Offline cdg

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Re: Multi-camera setup project.
« Reply #380 on: 11 / October / 2016, 20:56:04 »
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Its all about how Agisoft Photoscan (or any other software of this kind) works.


Photoscan produces a rough 3d model from a series of images.In order to do so , it tries to find common "points" in the images so it can calculate/guess the depth of the things in the images.
So , by projecting a pattern into the thing/person we are shooting , we just put more "points" for the Photoscan to find.
As a result , the produced 3d model , is very smooth , and the post-3d-processing is minimal.


Believe me when i say , if someone wears black/white/one-colored clothes or something that shines ...the model is a real mess...gaps everywhere , gaps we have to "close" by hand..not good.
I am kind of understand now.more points more details

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Offline cdg

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Re: Multi-camera setup project.
« Reply #381 on: 11 / October / 2016, 21:33:05 »
@cdg
For DSLR  & DLP projector combination - details were provided by Magnus in this thread:


http://www.agisoft.com/forum/index.php?topic=1324.0


With his multiple DLP projectors continuously running, he:


simultaneously triggered a group of Canon DSLR and Nikon DSLR. He took advantage of the shorter shutter lag of the Nikons to get all their shutters open & closed in 5ms and fire multiple off camera flash before the Canons' had opened their shutters:

  • ran 18 Canons (2 of 600D + 16 of 1100D) at  "long" 20ms shutter to pick up the projected noise for geometry

Simultaneously he

  • ran 4 cameras (Nikon D3200) at "short" 5ms shutter to pick up for texture only (i.e. not "drowned" by the continuous, relatively low intensity projected noise.
My memory is he had all camera remote shutter release wires (Canon & Nikon) simply connected together with splitters and a radio transmitter on one of the D3200 to trigger several off camera flash.


The benefits were impressive and described here:
http://www.agisoft.com/forum/index.php?topic=1324.msg6668#msg6668


"This first one was shot just with flash and as you can see it got 15877 points."

Then
"This next one we used the projectors too and this is what we got, 45733 points"

Based on this https://chdk.setepontos.com/index.php?topic=8312.msg107601#msg107601, it seems very unlikely to get all the "shutters" on a large bank of chdk cameras open and closed in a 5ms period - maybe 40ms, but that amount of dlp projected noise would probably adversely affect the flash texture capture.


To do this somewhere nearly as quickly (Edit1: maybe around 80ms across two separate banks of cameras) as the process that Magnus described using chdk cameras it therefore seems likely that the noise pattern must be projected using flash e.g. http://www.agisoft.com/forum/index.php?topic=1542.msg7960#msg7960


Edit2: I don't know how long the period was between the last Nikon shutter closing and the last Canon shutter opening so I don't know how long Magnus's 2 stage capture took from start to finish.
Thank you very much with such many information !!Yes for CHDK cameras ,it's looks two separate banks of  cameras could be a  easy way.

Re: Multi-camera setup project.
« Reply #382 on: 13 / October / 2016, 07:34:12 »
for CHDK cameras ,it's looks two separate banks of  cameras could be a  easy way.

Not necessarily easy & obviously expensive compared to  image capture on the same cameras (if you can live with a second or two between the 2 capture events).

Fyi - this comment refers to the 2 bank approach and either flash or DLP pattern projection
http://www.agisoft.com/forum/index.php?topic=1798.msg9565#msg9565

"Regarding the washing out of your diffuse textures, the solution to this is to have your system fire twice.  What I mean by this is that you can first take a shot with the speckle pattern being projected and then a split second later, take another this time with the projection muted. The second shot will NOT have patterns projected and this can be used for your texture.  Provided that the subject doesn't move much it will work. The key to this is to have the 2nd shot fire as fast after the first as possible. To do this you will need to use some sort of flash delay control device (such as the camera axe or pocketwizard max). This can also be done with dlp projectors, but a custom shutter system will have to be constructed, either electronic or mechanical."
« Last Edit: 13 / October / 2016, 08:14:05 by andrew.stephens.754365 »

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Offline cdg

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Re: Multi-camera setup project.
« Reply #383 on: 23 / October / 2016, 23:49:23 »
for CHDK cameras ,it's looks two separate banks of  cameras could be a  easy way.

Not necessarily easy & obviously expensive compared to  image capture on the same cameras (if you can live with a second or two between the 2 capture events).
I will avoid this situation.


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Offline cdg

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Re: Multi-camera setup project.
« Reply #384 on: 24 / October / 2016, 00:28:50 »
Not a big problem...power up the cameras..check what id each one is taking and then just start editing the file with ids to the desired physical order... :)
In changes through r624, I added a function set_id(old_id,new_id). If the script is running, the IDs on the camera will be updated immediately so you can see it on the ID display.

Once you are satisfied with the ID order, you can save the list.

If the new id is already in use they will be swapped. You can pass an optional third parameter 'error' to generate an error in this case instead.

Additionally, you can now select a range of cameras with mc:sel{min=number, max=number}

save_list works on the selected cameras, so this should make it easy to make subset lists.

I also fixed some bugs, see the svn log for details.
Hi  @reyalp
I am tried with this "set_id(old_id,new_id)",but still not know how to make it work.
old_id
old_id could be found by itself right? we don't need to set.
new_id
For multi-cam, how to give the IDs? one by one(i don't think so)?should be a list right?
Thank for you help !

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Offline reyalp

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Re: Multi-camera setup project.
« Reply #385 on: 24 / October / 2016, 02:20:09 »
I am tried with this "set_id(old_id,new_id)",but still not know how to make it work.
I don't really know what you are trying to do. I would suggest referring to the posts before that, where I added the list features, starting around https://chdk.setepontos.com/index.php?topic=11667.msg114745#msg114745 or referring to the source  https://app.assembla.com/spaces/chdkptp/subversion/source/HEAD/trunk/lua/multicam.lua#ln197

Beware some of the code may have changed since those posts were written.

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For multi-cam, how to give the IDs? one by one(i don't think so)?should be a list right?
IDs are assigned when you connect, in whatever order the USB library gives them. The set_id function is only needed if you want to change them, for example if you want a subset of cameras to have a particular ID range.

You can toggle display of the ID on the cameras screens using
Code: [Select]
!mc:cmd('id')

Note that mc:connect{add=true} will add new cameras with sequential IDs. So if you wanted IDs in a particular order, you could power on one, call connect, power on the next, call connect{add=true} and so on. If you save the id mapping when you are done, you only have to do this once.
Don't forget what the H stands for.

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Offline cdg

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Re: Multi-camera setup project.
« Reply #386 on: 22 / November / 2016, 03:29:30 »
In both cases after the second shooting , there are the aforementioned "error messages" that as you understand i don't remember them exactly :)
In the future, I suggest you copy and paste a sample somewhere. I don't have 64 cams, if I am going to debug the problem, I need some better idea of what is happening.

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I noticed some changes to some commands output ...less messages , doing the job hard to monitor.
I reduce the output because even with 3 cameras the flood of messages was difficult to follow. With 64, it's probably enough to slow things down noticeably...

If you are using mc:cmd() or mc:cmdwait() you can pass the option printcmd=true, like
 !mc:cmdwait('rec',{printcmd=true})
If you only want to print once for each command rather than each camera you can use
 !mc:cmdwait('rec',{printcmd='once'})

It the moment there is no way to do this with other functions like shoot that call cmdwait(). I will add a way to change the defaults for this at some point.

Some kind of status in the download command would be good.
edit:
Actually, you should be able to pass verbose=true in the mc:download_images options to see whats being downloaded.

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Since we can work with 1-2 cameras less ,and during a shooting is bad to say to client...wait a moment..technical issues...etc etc... is there a way when a camera loses connection , chdkptp will ignore this camera and keep working with the rest?It will be very handy if this can be done.
Yes, being able to ignore failed cams is something I would like to add, but it will take some work.
@reyalp
Hi reyalp:     how about the "ignore failed cams" function ?     when i try to connect my cameras,some times i could get one or two cameras failed,and it's takes me some time to find out which one :( :(  ,maybe the problem comes from the USB hub, i am think about changing it,but i think this "ignore failed cams" function will be helpful  .

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Offline mphx

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Re: Multi-camera setup project.
« Reply #387 on: 22 / November / 2016, 07:24:53 »
@cdg


If you are talking about the failed cameras , 99% the problem is the loose usb connection.


When a camera fails , we pull out / put in the usb cable on the camera side , we reconnect the cameras and the failed camera is working fine , until the end of shooting.


Probably after so many months/years of shooting the connection on the usb slot is not firm anymore.


But yes a feature tha could ignore the failed cameras would be very helpful.Reconnecting and re-syncing 64 cameras , is a bit of delay during a shooting.


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Offline mphx

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Re: Multi-camera setup project.
« Reply #388 on: 22 / November / 2016, 11:14:57 »
@reyalp


I can't find how the burst mode shooting is working .Can you provide a sample of the command?


Thanks


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Offline reyalp

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Re: Multi-camera setup project.
« Reply #389 on: 22 / November / 2016, 16:02:07 »
@reyalp


I can't find how the burst mode shooting is working .Can you provide a sample of the command?


Thanks
https://chdk.setepontos.com/index.php?topic=11667.msg128954#msg128954 ?
Don't forget what the H stands for.

 

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