【Python】OpenCV激活实时摄像头+创建多线程提升FPS

ericdiii

已于 2023-03-15 07:05:16 修改

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分类专栏： Python 文章标签： opencv python 计算机视觉

于 2022-08-19 22:45:35 首次发布

本文链接：https://blog.youkuaiyun.com/ericdiii/article/details/126433002

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本文介绍了如何使用OpenCV和多线程技术优化Webcam的帧率，通过myThread类实现并发读取和显示视频帧，以提高实时视频处理速度。

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使用OpenCV激活Webcam：

import cv2
from imutils.video import FPS

cap = cv2.VideoCapture(0)
fps = FPS().start()

while True:
    ret, frame = cap.read()
    cv2.imshow('frame', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    fps.update()

fps.stop()
print("[INFO] approx. FPS: {:.2f}".format(fps.fps()))

cap.release()
cv2.destroyAllWindows()

创建多线程提升FPS：

import numpy as np
import cv2
import threading
from copy import deepcopy
from imutils.video import FPS

thread_lock = threading.Lock()
thread_exit = False

class myThread(threading.Thread):
    def __init__(self, camera_id, img_height, img_width):
        super(myThread, self).__init__()
        self.camera_id = camera_id
        self.img_height = img_height
        self.img_width = img_width
        self.frame = np.zeros((img_height, img_width, 3), dtype=np.uint8)

    def get_frame(self):
        return deepcopy(self.frame)

    def run(self):
        global thread_exit
        cap = cv2.VideoCapture(self.camera_id)
        while not thread_exit:
            ret, frame = cap.read()
            if ret:
                frame = cv2.resize(frame, (self.img_width, self.img_height))
                thread_lock.acquire()
                self.frame = frame
                thread_lock.release()
            else:
                thread_exit = True
        cap.release()

def main():
    global thread_exit
    camera_id = 0
    img_height = 480
    img_width = 640
    thread = myThread(camera_id, img_height, img_width)
    thread.start()

    fps = FPS().start()

    while not thread_exit:
        thread_lock.acquire()
        frame = thread.get_frame()
        thread_lock.release()
        if frame.any()==0:
            continue
        else:
            cv2.imshow('Video', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            thread_exit = True
        fps.update()

    thread.join()
    fps.stop()
    print("[INFO] approx. FPS: {:.2f}".format(fps.fps()))

if __name__ == "__main__":
    main()

参考：[1] [2]