python解析rosbag

# coding:utf-8
#!/usr/bin/python

# Extract images from a bag file.

import sys
import os

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


left_path = str(sys.argv[2])+'/left/'   # 左目图像的路径，需提前手动创建，也可以使用程序自动创建
right_path = str(sys.argv[2])+'/right/'
depth_path = str(sys.argv[2])+'/depth/'

class ImageCreator():
    def __init__(self):

        print(sys.argv[1])

        # 创建文件夹
        if not os.path.exists(left_path):
            os.makedirs(left_path)
            print('创建文件夹',left_path)
        if not os.path.exists(right_path):
            os.makedirs(right_path)
            print('创建文件夹',right_path)
        if not os.path.exists(depth_path):
            os.makedirs(depth_path)
            print('创建文件夹',depth_path)


        self.bridge = CvBridge()
        print('提取中...')
        with rosbag.Bag(sys.argv[1], 'r') as bag:  # 读取bag文件，注意设置正确的bag文件路径
            for topic,msg,t in bag.read_messages():
                if topic == "/mynteye/left/image_color/compressed": # 左目图像的topic  /left /mynteye/left/image_color
                # if topic == "/left":
                        try:
                            # cv_image = self.bridge.imgmsg_to_cv2(msg,"bgr8")   # 不压缩的
                            cv_image = self.bridge.compressed_imgmsg_to_cv2(msg,"bgr8") # /compressed 压缩的
                        except CvBridgeError as e:
                            print(e)
                        # %.6f表示小数点后带有6位，可根据精确度需要修改
                        timestr = "%.6f" % msg.header.stamp.to_sec()
                        image_name = timestr + ".jpg" #图像命名：时间戳.png
                        cv2.imwrite(left_path + image_name, cv_image)  # 保存图像
                elif topic == "/mynteye/right/image_color/compressed": # 右目图像的topic  /right
                # elif topic == "/right":
                        try:
                            cv_image = self.bridge.compressed_imgmsg_to_cv2(msg,"bgr8")
                        except CvBridgeError as e:
                            print(e)
                        # %.6f表示小数点后带有6位，可根据精确度需要修改
                        timestr = "%.6f" % msg.header.stamp.to_sec()
                        image_name = timestr + ".jpg" #图像命名：时间戳.png
                        cv2.imwrite(right_path + image_name, cv_image)  # 保存图像
                elif topic == "/mynteye/depth/image_raw/compressed": # 深度图像的topic  /depth
                # elif topic == "/depth":
                        try:
                            cv_image = self.bridge.compressed_imgmsg_to_cv2(msg,"bgr8")
                        except CvBridgeError as e:
                            print(e)
                        # %.6f表示小数点后带有6位，可根据精确度需要修改
                        timestr = "%.6f" % msg.header.stamp.to_sec()
                        image_name = timestr + ".png" #图像命名：时间戳.png
                        cv2.imwrite(depth_path + image_name, cv_image)  # 保存图像
        print('提取结束')
  
if __name__ == '__main__': 
    try:
        image_creator = ImageCreator()
    except rospy.ROSInterruptException:
        pass