RpiCamera.py

from picamera2 import Picamera2
import cv2
import threading
import time
class FrameReader():
    def __init__(self,size):
        self.size=size
        self.queue = [None for _ in range(self.size)]
        self.offset = 0
    def pushQueue(self,data):
        self.offset = (self.offset + 1) % self.size
        self.queue[self.offset] = data
    def popQueue(self):
        self.offset = self.size -1 if self.offset -1 <0 else self.offset -1
        return self.queue[self.offset]

class Camera():
    is_running = False
    window_name = "Arducam PTZ Camera Controller Preview"
    frame = FrameReader(5)
    def start_preview(self,width=640,length=360):
        self.is_running = True
        self.capture_ = threading.Thread(target=self.capture_and_preview_thread, args=(width,length,))
        self.capture_.setDaemon(True)
        self.capture_.start()
    def stop_preview(self): 
        self.is_running = False
        self.capture_.join()
    def close(self):
        if(hasattr(self,"cam")):
            self.cam.stop()
            self.cam.close()
    def capture_and_preview_thread(self,width,length):
        self.cam = Picamera2()
        self.cam.configure(self.cam.create_still_configuration(main={"size": (width, length),"format": "RGB888"}))
        self.cam.start()
        while self.is_running == True:
            buf = self.cam.capture_array()
            self.frame.pushQueue(buf)
            cv2.imshow(self.window_name,buf)
            keyCode = cv2.waitKey(1)
            if(keyCode == ord('q')):
                break
        cv2.destroyWindow(self.window_name)
    def getFrame(self):
        return self.frame.popQueue()

if __name__ == "__main__":
    tmp = Camera()
    
    tmp.start_preview()
    time.sleep(5)
    tmp.stop_preview()