使用计时器捕获网络摄像头图像

Question

如何在图像捕捉期间获得休息？事实上，我需要在图像之间5秒。

此代码每秒捕获大约15-20张图像，但我需要在图像之间以5秒的间隔拍摄照片

import cv2
import time
import numpy

capture = cv2.VideoCapture(0)
capture.set(3,640)
capture.set(4,480)
img_counter = 0
frame_set = []
start_time = time.time()

while(True):
    ret , frame = capture.read()
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    frame_set.append(gray)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    end_time = time.time()
    elapsed = end_time - start_time
    img_name = "opencv_frame_{}.png".format(img_counter)
    cv2.imwrite(img_name,frame)
    print("{} written!".format(img_counter))
    img_counter +=1
    if elapsed > 1:

        capture.release()
        cv2.destroyAllWindows()
        time.sleep(3)

Answer 1

您需要一个if语句来检查是否已经过了所需的时间。使用已导入的时间包，您可以执行以下操作：

import cv2
import time

capture = cv2.VideoCapture(0)
capture.set(3, 640)
capture.set(4, 480)
img_counter = 0
frame_set = []
start_time = time.time()

while True:
    ret, frame = capture.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    cv2.imshow('frame', gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    if time.time() - start_time >= 5: #<---- Check if 5 sec passed
        img_name = "opencv_frame_{}.png".format(img_counter)
        cv2.imwrite(img_name, frame)
        print("{} written!".format(img_counter))
        start_time = time.time()
    img_counter += 1

上面的脚本将每隔5秒将帧保存为RGB到工作目录。