United Kingdom
Asked — Edited

Videostream

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Hi,

I would like to extend the pyJD (https://github.com/BrutusTT/pyJD) project to support video streaming for the JD Humanoid Robot. Is there any way to retrieve the camera images without using the EZB software stack?

The idea is to integrate the robot into an Yarp-based experiment setup. From the information on the forum I was able to control the servos via telnet. But now I'm stuck on accessing the camera. Unfortunately, using the Windows OS and ARC is not an option for the setup but I don't mind tinkering with low-level communication for the robot.

Cheers, BrutusTT


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#1  

I think that the ez-bs camera is like a wifi camera. Though I'm not sure whether it is encoded or not.

#2  

It is a custom video stream that DJ developed for performance, but he has stated in the past he would share how to connect. I forget if he was going to say how to connect a custom camera to the EZ-B or how to use custom software to read from the EZ-B though.

Alan

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Synthiam
#3  

The code is pretty straight forward to create a library for any application. Take a look at the univeralBot in the software section. Let me know if you have any questions.

United Kingdom
#4  

Thanks for the pointer. I found the class but was not able to test it yet because the battery of our robot died. I will let you know if I got it working once that problem is solved.

Cheers, BrutusTT

United Kingdom
#5  

Batteries are finally here:)

I had a look at EZBv4Video which looks like the stuff I need. However, I can not figure out the port I need to connect to as it seems not to be port the telnet or http port. Scanning with nmap also did not provide another port that I could use.

I know that in the ARC you can activate a Videostream port but since I can not use ARC I can not do this switch.

Is there any other method to activate the video stream port? Did I miss something?

United Kingdom
#7  

Thanks

I finally managed to fill my image buffer starting with EZIMG magic header. Only question remaining is:

How do I decode the buffer into something that I can save as an image or image stream? Easiest for me would be to convert the EZ image to an OpenCV image.

Any ideas where to look for the decoding?

United Kingdom
#8  

Ok, I guess I found the solution.

The buffer contains an JPEG/JFIF encoding and after removing the first couple of bytes its working.

In case someone wants to do it as well:

  1. separate the data by EZIMG as magic header
  2. remove the starting bytes before "FF D8" which is the start sequence of the image also called SOI (https://de.wikipedia.org/wiki/JPEG_File_Interchange_Format)
  3. put the buffer data into something that can read jpeg images.
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