关于从rosbag文件提取图像,ros官网上给出了使用建立launch文件的方法。 我们也可以通过编写Python程序按照我们想要的信息及方式来提取。
在本例中,我想把每张图像的时间戳也提取出来,于是就查阅资料,然后动手试一下吧。
带时间戳提取
该程序 实现了读取一个bag文件,将ros msg形式 转换为 cv 图像形式,保存在文件夹中。图像名称 即为时间戳。
另外:改程序提取的图像直接保存在了和 .py 程序,在同一级文件夹下。
# 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 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 rgb_path = '/home/david/workspace/bags/rgb/' depth_path= '/home/david/workspace/bags/depth/' class ImageCreator(): def __init__(self): self.bridge = CvBridge() with rosbag.Bag('/home/david/workspace/bags/loudao.bag', 'r') as bag: #要读取的bag文件; for topic,msg,t in bag.read_messages(): if topic == "camera/rgb/image_raw": #图像的topic; try: cv_image = self.bridge.imgmsg_to_cv2(msg,"bgr8") except CvBridgeError as e: print e timestr = "%.6f" % msg.header.stamp.to_sec() #%.6f表示小数点后带有6位,可根据精确度需要修改; image_name = timestr+ ".png" #图像命名:时间戳.png cv2.imwrite(rgb_path + image_name, cv_image) #保存; elif topic == "camera/depth_registered/image_raw": #图像的topic; try: cv_image = self.bridge.imgmsg_to_cv2(msg,"16UC1") except CvBridgeError as e: print e timestr = "%.6f" % msg.header.stamp.to_sec() #%.6f表示小数点后带有6位,可根据精确度需要修改; image_name = timestr+ ".png" #图像命名:时间戳.png cv2.imwrite(depth_path + image_name, cv_image) #保存; if __name__ == '__main__': #rospy.init_node(PKG) try: image_creator = ImageCreator() except rospy.ROSInterruptException: pass