[libdc1394-devel] Re: frame rate in extrernal trigger mode

[Johann S. <j.s...@ir...>]

Boris Zingerman wrote:
> I have a question regarding frame rate. When using
> isochronous mode, time per frame is approximately
>      max( read_out_time, shutter_time)
> because camera performs acquisition of next frame
> while sending previous frame. When using one-shot
> mode time per frame is approximately 
>      read_out_time + shutter_time
> My question is what happens when using external
> trigger ? If camera obtains trigger while sending frame
> to host, will it begin exposure/acquisition immediately
> or will wait for read-out completion ?

What do you mean by "read_out_time"?  The time taken to transfer the 
contents of the sensor to an internal camera buffer, or the time taken 
to transmit the contents of the internal buffer via the bus to the PC? 
  It sounds as if you have one of those cameras that can start 
transmission of a frame before it has finished reading the image out 
of the sensor.  In that case an external trigger will have to wait 
until the whole sensor content has been read out.

Johann

-- 
Johann Schoonees                          Research Engineer
Industrial Research Ltd, PO Box 2225, Auckland, New Zealand
Phone +64 9 9203679  Fax +64 9 3028106       www.irl.cri.nz

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