rosbagtofiles

# coding:utf-8
#!/usr/bin/python
 
# Extract images from a bag file.
 
#PKG = 'beginner_tutorials'
import roslib   #roslib.load_manifest(PKG)
import rosbag
import rospy
import decimal
import cv2
from sensor_msgs.msg import Image
from cv_bridge import CvBridge
from cv_bridge import CvBridgeError
 
# Reading bag filename from command line or roslaunch parameter.
import os
#import sys
 
camera0_path = '/home/yh2020/slam_data/realsence_bag/color/'
camera1_path = '/home/yh2020/slam_data/realsence_bag/depth/'
 
class ImageCreator():
 
 
    def __init__(self):
        self.bridge = CvBridge()
        with rosbag.Bag('/home/yh2020/slam_data/realsence_bag/Normal_robot.bag', 'r') as bag:  #要读取的bag文件；
            f = open("timestamp.txt",'w')
            f1 = open("depthstamp.txt",'w')
            for topic,msg,t in bag.read_messages():
                if topic == "/camera/color/image_raw": #图像的topic；
                        try:
                            cv_image = self.bridge.imgmsg_to_cv2(msg,"bgr8")
                        except CvBridgeError as e:
                            print e
                        timestr = msg.header.stamp.to_sec()
                        timer = 1e9 * timestr
                        timestamp = "%d" % timer
                        f.write(timestamp)
                        f.write('\n')
                        image_name = "%d" % timer + ".png" #图像命名：时间戳.png
                        cv2.imwrite(camera0_path + image_name, cv_image)  #保存；
                elif topic == "/camera/aligned_depth_to_color/image_raw": #图像的topic；
                        try:
                            cv_image = self.bridge.imgmsg_to_cv2(msg,"16UC1")
                        except CvBridgeError as e:
                            print e
                        timestr = msg.header.stamp.to_sec()
                        timer = 1e9 * timestr
                        timestamp = "%d" % timer
                        f1.write(timestamp)
                        f1.write('\n')
                        image_name = "%d" % timer + ".png" #图像命名：时间戳.png
                        cv2.imwrite(camera1_path + image_name, cv_image)  #保存；
            f.close()
            f1.close()
if __name__ == '__main__':
 
    #rospy.init_node(PKG)
 
    try:
        image_creator = ImageCreator()
    except rospy.ROSInterruptException:
        pass