extract images from bag file python
#!/usr/bin/env python # -*- coding: utf-8 -*- # Copyright 2016 Massachusetts Institute of Technology # updated just two lines vs the original """Extract images from a rosbag. """ import os import argparse import cv2 import rosbag from sensor_msgs.msg import Image from cv_bridge import CvBridge def main(): """Extract a folder of images from a rosbag. """ parser = argparse.ArgumentParser(description="Extract images from a ROS bag.") parser.add_argument("bag_file", help="Input ROS bag.") parser.add_argument("output_dir", help="Output directory.") parser.add_argument("image_topic", help="Image topic.") args = parser.parse_args() print "Extract images from %s on topic %s into %s" % (args.bag_file, args.image_topic, args.output_dir) bag = rosbag.Bag(args.bag_file, "r") bridge = CvBridge() count = 0 for topic, msg, t in bag.read_messages(topics=[args.image_topic]): # update the desired_encoding to rgb8 or bgr8 or something else ... depending on your sensor cv_img = bridge.imgmsg_to_cv2(msg, desired_encoding="passthrough") cv2.imwrite(os.path.join(args.output_dir, "frame%06i.png" % count), cv_img) count += 1 print("Wrote image %i" % count) bag.close() return if __name__ == '__main__': main()
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