ros python发布者订阅者，opencv 获取摄像头图像，由发布者发布，订阅者接收转为bag文件

talker.py

ubuntu18.04 + ros melodic + cv2

#!/usr/bin/env python3
# coding:utf-8

import cv2
import numpy as np
import rospy
from std_msgs.msg import Header
from sensor_msgs.msg import Image
from cv_bridge import CvBridge , CvBridgeError
import time

if __name__=="__main__":
    capture = cv2.VideoCapture(0) # 定义摄像头
    rospy.init_node('camera_node', anonymous=True) #定义节点
    image_pub=rospy.Publisher('/image_view/image_raw', Image, queue_size = 1) #定义话题

    while not rospy.is_shutdown():    # Ctrl C正常退出，如果异常退出会报错device busy！
        start = time.time()
        ret, frame = capture.read()
        if ret: # 如果有画面再执行
            # frame = cv2.flip(frame,0)   #垂直镜像操作
            frame = cv2.flip(frame,1)   #水平镜像操作
            ros_frame = Image()
            header = Header(stamp = rospy.Time.now())
            header.frame_id = "Camera"
            ros_frame.header=header
            ros_frame.width = 640
            ros_frame.height = 480
            ros_frame.encoding = "bgr8"
            ros_frame.step = 1920
            ros_frame.data = np.array(frame).tobytes() #图片格式转换
            image_pub.publish(ros_frame) #发布消息
            end = time.time()
            print("cost time:", end-start ) # 看一下每一帧的执行时间，从而确定合适的rate
            rate = rospy.Rate(25) # 10hz
    capture.release()
    cv2.destroyAllWindows()
    print("quit successfully!")

listener.py

#!/usr/bin/env python2.7
import rospy
import numpy as np
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError
import cv2
from ros import rosbag

bridge = CvBridge()

bag = rosbag.Bag("video.bag", 'w')

frame_id = 0
prop_fps = 25


def callback(data_value):
    global frame_id
    stamp = rospy.rostime.Time.from_sec(float(frame_id) / prop_fps)
    frame_id += 1
    data_value.header.stamp = stamp
    data_value.header.frame_id = "camera"
    bag.write("/image_view/image_raw", data_value, stamp)
    if frame_id == 100:
        bag.close()


if __name__ == '__main__':
    rospy.init_node('img_process_node', anonymous=True)
    rospy.Subscriber('/image_view/image_raw', Image, callback)
    rospy.spin()