Multiple-camera synchronization with same ISP setting

l4es

Dear ISP Experts,

It is very interesting to see that the RVC3 based OAK SoM Pro S3 and OAK SoM MAX are now available for purchasing. The combination of one of these SoMs with suitable FFC xP board allows to have different multiple-camera configurations. And my most important interest is the synchronization btw the sensor modules which includes frame / hardware synchronization and ISP settings synchronization, especially in stereo vision.

While frame / hardware synchronization can be done at sensor's level by re-wiring the relevant signals btw them, I wonder if the ISP setting synchronization could be also done? By ISP setting (converted to sensors' I2C registers setting) synchronization. And we are struggling with our current platform that each sensor is controlled by an instance of the ISP therefore there's possibility that each sensor has a different set of I2C register values at a time and this could be harmful for stereo vision algo. I would be better if there's an option to force the ISP setting of the master sensor to other slave sensors (like to case of Nvidia Argus library to open single capture session for multiple cameras).

Best Regards,
Khang

l4es

Hi,

Any thoughts on this, please ?

Khang

erik

Hi l4es ,
We apologize for missing this question, I have just checked with the team.

l4es

Hi erik ,

Do you think if the statement "The B & C (or Left & Right) ports are synced by sharing the same I2C bus" in the following discussion is relevant to my question : https://discuss.luxonis.com/d/934-ffc-4p-hardware-synchronization/4

Why do they need to share the same I2C bus in order to be synced? I was thinking that they could be frame synced by just wiring their hardware sync signals together and externally triggering in case of input-only FSYNC (as the case of AR0234). And sharing the same I2C bus, even same I2C address (like the case of some Sony sensors, the slave could be in mute mode, i.e. it can receive the I2C commands but ignores the ACK to avoid conflicting the I2C bus) might only be for purpose of sharing the same I2C setting (translated from same ISP configuration) ?

Best Regards,
Khang Le Truong

erik

Hi l4es , Perhaps for such low-lvl questions it would be better to open issue on depthai-core, so you can get in touch with FW engineers directly.

I2C bus - exposure/sensitivity are shared across stereo pairs, as otherwise, disparity/depth frames wouldn't be accurate.

l4es

Hi erik,

Perhaps for such low-lvl questions it would be better to open issue on depthai-core, so you can get in touch with FW engineers directly.

Thank you. I will consider to open the ticket if necessary after testing and validating your below comment :

I2C bus - exposure/sensitivity are shared across stereo pairs, as otherwise, disparity/depth frames wouldn't be accurate.

It is already good that the stereo pairs share the same exposure/sensitivity.

Best Regards,

Khang Le Truong