Example Thread Class for Pi Camera Array

[pageauc]

I have written a picamera2 class that runs pi camera capture array in a thread similar to Imutils picamera stream by Adrian Rosebrock. You may want to include in your Examples.
Class example here
https://raw.githubusercontent.com/pageauc/MoTrack-Picam2-Demo/master/streampilibcam.py

Demo code here https://github.com/pageauc/MoTrack-Picam2-Demo

[davidplowman]

Hi, and thank you for the example.

I was wondering if you had any (very simple!) example code that showed how to drive it, and why one might use it. Thanks!

[ballen4705]

I have written a picamera2 class that runs pi camera capture array in a thread

Your thread has a loop which sleeps for 10 milliseconds, then calls capture_array. Another way to get regular access to an in-memory copy of the camera data is to attach a callback function to the picamera2 loop. See pre_callback and post_callback in sections 8.2 and 9.4 of The Picamera2 Library, which also contains several examples. My understanding is that this avoids the overhead of copying. To quote the manual: "Finally we draw attention to the MappedArray class. This class is provided as a convenient way to gain in-place access to the camera buffers - all the capture methods that applications normally use are returning copies."

[carterw]

I'm a novice on this, but it seems to me that the copy is done so that an image buffer wouldn't get overwritten while it is being subsequently processed by some code.

[davidplowman]

Hi, I'm thinking of converting this to a discussion rather than an "issue", would that make sense? Thanks!