how to used extern synchronous triger

志鹏 于 1 Reputation point
2022-10-22T12:09:39.18+00:00

Hello, I'm happy to use Azure Kinect and I want to collect synchronous depth data from 8 Azure Kinect and 8 industrial camera.
In order to do this, I design a extern synchronous triger generator to create the synchronous signal.
However, in my test, I find that the synchronous triger seems can only control the start of the acquisition. Even I pulling out the 3.5mm synchronous line, the slave camera is still working.
I suspect there is something wrong with my extern synchronous triger generator, so I observe the synchronous output waveform of the Azure Kinect with an oscilloscopesignal, and use a signal generator to create same waveform as extern synchronous triger signal. But the problem is still exists.
does the camera can not capture every frame synchronously or I forgot some thing need to do ?
Your reply will be appreciated.

Azure IoT
Azure IoT
A category of Azure services for internet of things devices.
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  1. 志鹏 于 1 Reputation point
    2022-10-22T12:11:26.677+00:00

    I follow the guide in https://video2.skills-academy.com/zh-cn/azure/kinect-dk/multi-camera-sync
    And I noticed that there is a note in this picture.
    253243-sub-device-start.png
    sub-device-start
    It says that "The camera will not start untill it receives a start singal from the master device". Is that means only the first triger signal make sense?

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  2. QuantumCache 20,266 Reputation points
    2022-10-24T18:16:37.727+00:00

    Hello @志鹏 于 ,

    Since you are viewing a slave device, the Azure Kinect Viewer will not display the image after the device has booted.

    The image will not be displayed until the slave device receives a sync signal from the master device.

    Did you try below steps?

    • After starting the slave device, open the master device with another instance of the Azure Kinect Viewer.
    • Under External Sync, select Primary.
    • Select "Start".
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  3. 志鹏 于 1 Reputation point
    2022-10-29T04:48:25.123+00:00

    @QuantumCache
    hello,thanks for your answer.

    I try an experiment as you say:
    "After starting the slave device, open the master device with another instance of the Azure Kinect Viewer.
    Under External Sync, select Primary.
    Select "Start"."

    I found that the slave device do start work when I start the master. However, when I stop the master device or pull out the 3.5mm synchronous line, the slave device still work, which means the slave device is not capture with the hardware synchronous triger in frames other than the first frame.

    that cause a problem:
    when I want to use the 8 Azure Kinect and 8 industrial camera to work together to capture a long sequence, I am not sure if the Azure Kinect still be synchronous to the industrial camera.
    As you know, so many camera can't be connect to only one conmputer due to the bandwidth limitation. In fact, I use 4 compute to do this. that means I need to use the extern hardware synchronous triger to make sure every frame was capture at the same time.

    Any idea to help me? Thank you very much.


  4. 志鹏 于 1 Reputation point
    2022-11-08T06:20:27.193+00:00

    Hello, @QuantumCache , here is the detail infomation of my experience:
    step 0 : I connect two Azure Kinect to one computer.

    step 1 : I open two device in two Azure Kinect Viewer application, and set one as master, and the other is slave:

    258079-step1.png

    step 2 : I start the slave camera, and it don't work, which is right in my opinion

    258058-step2.png

    step 3 : Then I start the master camera, and both two camera start to work, which is right in my opinion, too

    258059-step3.png

    step 4 : Howerver, when I stop the master camera, even pulling out the 3.5mm synchronous line, the slave camera is still working. That confiused me, In my opinion, the slave camera should capture one times when it received a triger from the master camera, and it shouldn't work without the triger from the master camera.

    258080-step4.png

    So, the problem is :
    Can the Azure Kinect in slave mode capture each frame Accurately on each triger? A triger is just like clicking the shutter once

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