• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 30 subscribers
  • Views 1735 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Synchronization of OPT8241 ToF Cameras

Stanislav Kunt
Prodigy 100 points
Other Parts Discussed in Thread: OPT8241, OPT9221

Hi,

is it possible to synchronize two OPT8241 based cameras, so that the first camera will integrate while the other one is in the quad dead time? I would like to use multiple cameras simultaneously in one room and to use time-multiplexing to prevent interferences.

Thanks.

Stanislav

  • 0
    TI__Expert 3800 points
    Hi Stanislav,

    It is indeed possible to synchronise the cameras such that one camera's integrates in another's dead time/readout time. OPT9221 has a pin called VD_IN. Frames can be synchronised to clock edges on this pin.
    One of the ways to do this would be to have some means of synchronising the cameras in the room and then assigning a different time offset from the synchronisation instant. This can bee done through a register setting given the chipset is being driven in "Slave mode" by giving a pulse at the VD_IN pin.
    There could be other back-off based techniques as well.

    Regards,
    Subhash
  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 100 points
    Hi Subhash,

    thanks for your anwer! Is there any way how to achieve the synchonization by software (from VoxelSDK)? My idea: If the cameras are in interference, then delay one of the cameras so long until it integrates while the other one is in the dead time.
    Thanks a lot.

    Stanislav
  • 0 in reply to Stanislav Kunt
    TI__Expert 3800 points
    Hi Stanislav,

    So you are interested in the back-off based technique where we don't need to make hardware change. The OPT8241 CDK doesn't run in slave mode. So I am not sure how to delay a given stream of frames by an accurately predictable amount of time.
    You could do something like the following:

    set tg_dis = True
    wait(t)
    set tg_dis = False

    The time 't' could be chosen per your back-off algorithm. Your frame synchronisation time would shift by some time which would be related to 't'.
    Each of the register writes would take some time which might not be very predictable. So doing this without using the hardware mode of running in "Sync Mode" might give results which depend on parameters external to the chipset's capabilities. The correct way of doing this would be to run the camera in "sync mode" by giving a sync input at VD_IN. You can then set a register "frame_sync_delay" which can give you predictable synchronised delays.
    Please let me know if this answers your question.

    Regards,
    Subhash
  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 100 points
    Hi Subhash,

    thanks a lot for your answers. I will try both purposed methods and see which one suits better my needs.

    Best regards,
    Stanislav