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Face Detection

The test program will pull the camera data, add the face detection algorithm, and use tools such as VLC to pull the stream in real time to view the effect.


Face detection program source code location:

Refer to the method in the previous chapter Introduction to compile the sample program.

Send test program and model files to Duo

  • Refer to the method in the Boot the Duo chapter to install the system

  • Refer to the method in the Camera chapter to power on the Duo after connecting the camera

Send the compiled sample_vi_fd to the Duo board through the scp command on your PC:

scp sample_vi_fd [email protected]:/root/

Also use scp to send the model file used for face detection in the cvimodel directory to the Duo board:



Duo256M and DuoS:


Run the example

Log in to the Duo terminal through the serial port or ssh.

Add executable permissions to the test program in Duo's terminal

chmod +x sample_vi_fd

Execute the test program in Duo's terminal:


./sample_vi_fd scrfd_480_270_int8.cvimodel

Duo256M and DuoS:

./sample_vi_fd scrfd_768_432_int8_1x.cvimodel

The following information will be displayed in the Duo terminal:

Initialize RTSP
version: 1.4.0
scrfd768432 Build at 2023-12-25 01:21:44 For platform cv181x
Max SharedMem size:1658880

At this time, point the camera at the face, and the Duo terminal will print the number of faces detected by the camera in real time:

face count: 5
face count: 6
face count: 5
face count: 4
face count: 0
face count: 1
face count: 0

Use VLC to pull streams on PC to view the effect

Open VLC media player, click Media in the upper left corner, select Open Network Stream, and enter the URL.

If you are using USB Net(RNDIS), the address is:

Document Pictures

If you are using the network port on the IO-Board or the network port integrated on DuoS, the IP address in the URL needs to be replaced with the IP of the network port (you can use the ifconfig command in the Duo terminal to view).

Click the Show more options option in the lower left corner, and you can set the Caching option to adjust the delay. The default is 1000 milliseconds, which is 1 second. When the network environment is good, such as in a LAN, you can turn it down to reduce latency. You can set it to 100 to 300. If the network environment is poor or the screen freezes, you can try to increase it.

After configuring, click Play to view the face detection effect of the camera.

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