Hi,

Currently I am using a Pointgrey Firefly2 camera (IEEE1394) with
ARToolkit 2.65 on Linux. I would like to do stereo processing using a
second Firefly2.

The idea is to connect the two cameras on separate IEEE1394 buses (but
on one computer) in order to get 30 fps at a resolution of 640x480. To
my knowledge that should be possible using ARToolkit 2.70 and libdc1394
0.9.1. Has anyone successfully been working with such a setup?

Since it is not possible to synchronize Firefly2 cameras, the images are
acquired at different points in time. Will this lag be noticeable to the
user (I presume it is not, for the lag is likely to be pretty short)?

Regards,

Tobias Laubach

I'll confirm what Philip says:  640x480 RGB would only support one 
camera.  But, most firewire cameras only support streams up to 200mbps, 
which i distinctly remember being annoyed about when I found out all 
our cameras (an older videre dcam, unibrain fire-i) won't do 
640x480@3 .... RGB.

I suspect the inter-camera lag will add noise, but won't be a huge 
issue ...

On Jan 18, 2005, at 3:04 PM, Philip Lamb wrote:

> At 12:50 PM +0100 1/18/05, Tobias Laubach wrote:
>> Hi,
>>
>> Currently I am using a Pointgrey Firefly2 camera (IEEE1394) with
>> ARToolkit 2.65 on Linux. I would like to do stereo processing using a
>> second Firefly2.
>>
>> The idea is to connect the two cameras on separate IEEE1394 buses (but
>> on one computer) in order to get 30 fps at a resolution of 640x480. To
>> my knowledge that should be possible using ARToolkit 2.70 and 
>> libdc1394
>> 0.9.1. Has anyone successfully been working with such a setup?
>>
>> Since it is not possible to synchronize Firefly2 cameras, the images 
>> are
>> acquired at different points in time. Will this lag be noticeable to 
>> the
>> user (I presume it is not, for the lag is likely to be pretty short)?
>>
>> Regards,
>>
>> Tobias Laubach
>
> Depending on what data format the FireFly is returning, you may not 
> need 2 separate busses. I've been using 2 unibrain fire-i cameras on a 
> Mac on a single 1394 bus and getting 640x480 @ 30 fps from both. A 
> quick calculation, given that the fire-i returns YUV 16 bit pixels 
> gives 147 Mbps per isoschronous channel, excluding signalling 
> overhead. So there's plenty of room for 2 of those on a 400 Mbps 1394 
> bus. If the firefly returns RGB pixels you'd need 2 busses though.
>
> As for inter-camera lag.. hard to quantify, but it certainly hasn't 
> been enough to bother me in casual use.
>
> Regards,
> Phil.

At 12:50 PM +0100 1/18/05, Tobias Laubach wrote:
>Hi,
>
>Currently I am using a Pointgrey Firefly2 camera (IEEE1394) with
>ARToolkit 2.65 on Linux. I would like to do stereo processing using a
>second Firefly2.
>
>The idea is to connect the two cameras on separate IEEE1394 buses (but
>on one computer) in order to get 30 fps at a resolution of 640x480. To
>my knowledge that should be possible using ARToolkit 2.70 and libdc1394
>0.9.1. Has anyone successfully been working with such a setup?
>
>Since it is not possible to synchronize Firefly2 cameras, the images are
>acquired at different points in time. Will this lag be noticeable to the
>user (I presume it is not, for the lag is likely to be pretty short)?
>
>Regards,
>
>Tobias Laubach

Depending on what data format the FireFly is returning, you may not 
need 2 separate busses. I've been using 2 unibrain fire-i cameras on 
a Mac on a single 1394 bus and getting 640x480 @ 30 fps from both. A 
quick calculation, given that the fire-i returns YUV 16 bit pixels 
gives 147 Mbps per isoschronous channel, excluding signalling 
overhead. So there's plenty of room for 2 of those on a 400 Mbps 1394 
bus. If the firefly returns RGB pixels you'd need 2 busses though.

As for inter-camera lag.. hard to quantify, but it certainly hasn't 
been enough to bother me in casual use.

Regards,
Phil.