Need clear description of setSyncSensorSessionsCount()

[khang.l4es]

Dear Forum,

I am trying to implement the single capture session for dual sensors of a stereo camera. I saw in the syncStereo sample, there’s the following code snippet :

As I do not have a Hawk stereo camera to test with, I would like to know to use correctly/how to pass correct arguments to the setSyncSensorSessionsCount() method, please ?

Concretely, for our system with a single stereo camera having dual sensors, what values should I give to the dualSensors and singleSensor of the setSyncSensorSessionsCount() API? Especially what happens with value 0?

I am working with Jetpack-5.1.2 (R35.4.1) for information.

Thanks in advance and best regards,
Khang

[ShaneCCC]

Here is the details as per public header:

    /**
     * Sets the number of sessions needed for dual and/or single sensors sync session usecase.
     * @param[in] dualSensors Number of sessions needed for dual sync sensors.
     * @param[in] singleSensor Number of sessions needed for single sync sensors.
     *
     * @returns success/status of the call.
     */
    virtual Status setSyncSensorSessionsCount(uint32_t dualSensors, uint32_t singleSensor) = 0;
 
Here dualSensors  means they will be running in sync as a stereo pair, in your case only single stereo pair need to be executed in sync so dualSensors should 1.
As singleSensor meant for mono cameras that are not part of stereo sync pair, in your case no camera is there as mono so singleSensor should 0.

[khang.l4es]

Hi @ShaneCCC,

Currently my problem with opening a capture session / camera is that their timestamps differs significantly. I also tried getSoFTimestampTsc() but this later did not help. Do you think that the setSyncSensorSessionsCount(1, 0) could help me to solve the issue?

Best Regards,
K

[ShaneCCC]

This API is base on the sensor have HW sync design like GMSL F-SYNC if your HW don’t have the HW support that couldn’t sync the frame correctly.

Thanks

[khang.l4es]

Hi @ShaneCCC,

I have a pair of global shutter camera sensors and they are externally triggered with same signal. I also tried setSyncSensorSessionsCount(1, 0), setSyncSensorSessionsCount(0, 1) and setSyncSensorSessionsCount(0, 0) but they all gave similar result : no timediff btw the frames of the 2 camera sensors :

[ArgusCapture] Left frame #155 captured at 590855654000
[ArgusCapture] Right frame #155 captured at 590855654000
[ArgusCapture] Left frame #156 captured at 590905656000
[ArgusCapture] Right frame #156 captured at 590905656000
[ArgusCapture] Left frame #157 captured at 590955657000
[ArgusCapture] Right frame #157 captured at 590955657000
[ArgusCapture] Left frame #158 captured at 591005658000
[ArgusCapture] Right frame #158 captured at 591005658000
[ArgusCapture] Left frame #159 captured at 591055659000
[ArgusCapture] Right frame #159 captured at 591055659000
[ArgusCapture] Left frame #160 captured at 591105659000
[ArgusCapture] Right frame #160 captured at 591105659000
[ArgusCapture] Left frame #161 captured at 591155660000
[ArgusCapture] Right frame #161 captured at 591155660000
[ArgusCapture] Left frame #162 captured at 591205662000
[ArgusCapture] Right frame #162 captured at 591205662000
[ArgusCapture] Left frame #163 captured at 591255663000
[ArgusCapture] Right frame #163 captured at 591255663000

[ShaneCCC]

This API use to sync capture request for stereo sensors to avoid frame un-sync. Suppose you can reference to the sample to implement your case.