python Thread 實現多線程的一個例子

下面是一個使用python Thread 實現多線程的例子，圖像的獲取和特徵點提取是獨立的線程。

import cv2
from threading import Thread
import copy
import numpy as np 


class VideoGet:
    """
    Class that continuously gets frames from a VideoCapture object
    with a dedicated thread.
    """

    def __init__(self, src=0):
        self.stream = cv2.VideoCapture(src)
        (self.grabbed, self.frame) = self.stream.read()
        self.stopped = False

    def start(self):    
        Thread(target=self.get, args=()).start()
        return self

    def get(self):
        while not self.stopped:
            if not self.grabbed:
                self.stop()
            else:
                (self.grabbed, self.frame) = self.stream.read()

    def stop(self):
        self.stopped = True


class VideoShow:
    """
    Class that continuously shows a frame using a dedicated thread.
    """

    def __init__(self, frame=None):
        self.frame = frame
        self.stopped = False

    def start(self):
        Thread(target=self.show, args=()).start()
        return self

    def show(self):
        out = self.frame
        cv2.namedWindow("Fast Feature",cv2.WINDOW_NORMAL)
        while not self.stopped:
            gray = cv2.cvtColor(self.frame, cv2.COLOR_BGR2GRAY)
            fast = cv2.FastFeatureDetector_create()
            kps3 = fast.detect(gray, None)
            cv2.drawKeypoints(gray, kps3, out, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)
            cv2.imshow("Fast Feature", out)
            if cv2.waitKey(1) == ord("q"):
                self.stopped = True

    def stop(self):
        self.stopped = True


def threadBoth(source=0):

    video_getter = VideoGet(source).start()
    video_shower = VideoShow(video_getter.frame).start()

    while True:
        if video_getter.stopped or video_shower.stopped:
            video_shower.stop()
            video_getter.stop()
            break

        frame = video_getter.frame
        video_shower.frame = frame

if __name__ == "__main__":
    threadBoth(0)

參考：https://github.com/nrsyed/computer-vision/tree/master/multithread