camera recommendations?

[John Goodrich]

Hi Rebecca,

I see that no one ever responded to your post, but did you ever figure out 
a solution to this problem? I am designing a preferential looking task that 
seems similar to the task you described, only I am using a webcam to record 
the eye movements. I would like to be able to have E-Prime tell the webcam 
to start recording when the experiment begins so that the onset times of 
objects in the E-Prime output can be directly used to identify when in the 
video the two images appear to let me know when to begin coding eye 
movements. 

Thanks,

John Goodrich

On Friday, October 18, 2013 10:21:29 PM UTC-4, Rebecca Lundwall wrote:
>
> I am trying to get a new research lab set up. I use EPrime to present 
> stimuli and a camera to collect eye movement data. I am working with the 
> college's computer services and they asked me to contact this group and see 
> if you had recommendations on *camera specs* for the following situation. 
> PSTNET support also suggested that I ask this question here. I do not use 
> eye-tracking equipment because it does not work well with young infants. 
>
> My question is if anyone knows of a camera or camera set-up that would 
> work without the ForA timer. My key concern is having a time-stamp on the 
> video and that the time-stamp is controlled (started and stopped) by EPrime 
> presenting the stimulus. I will describe how we have done this in the past, 
> but I can no longer find a supported For-A video timer VTG-33 (which 
> reports frames) and we are nervous about buying the one I found on Ebay. 
>
> In the experiment:
> 1) E-Prime simultaneously sends an image to a monitor and starts the ForA 
> timer (or it could start the camera's timer)
> 2) The ForA timer (if used) puts a time stamp on the digital video 
> recording. The timestamp starts and runs until EPrime tells it to stop. 
> Stopping the clock is important so that trials are separated and RAs don't 
> get confused when they go back and code for eye movement latency and 
> direction (left or right). If I used the camera's internal clock, EPrime 
> would need to start and stop it's clock or start and stop the entire camera.
> 3) the digital video with the time stamp are sent back for storage on the 
> computer
> 4) the digital files are opened  with a video editing software) that can 
> detect scenes based on lighting conditions (the presentation of a new 
> stimulus triggers a new scene); we number the scenes and two RAs code them 
> for eye movement latency and direction. 
>
> So, does anyone know of a camera that has a timestamp down to the frame 
> level and that can be synced with the presentation of a stimuli by EPrime? 
> Other info or related questions: 
> *the camera must work in low-light conditions
> *there are approximately 50-60 trials for infants and 200 for children, 
> each is presented for between 67 msec - 4 sec 
> *I care about response differences as small as 10-20 msec (so am thinking 
> about a camera with 60 fps or more)
> *is 60 Hz sufficient for the CPU?  If I get more fps on the camera do I 
> need higher refresh rate as well?
>  
> Thanks for your help.
>

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to e-prime+unsubscribe at googlegroups.com.
To post to this group, send email to e-prime at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/e-prime/b0242a2f-0895-4d2f-9c77-a99c9b1d2954%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.linguistlist.org/pipermail/eprime/attachments/20140507/c44e83fe/attachment.htm>