使用ROS rosbag工具进行过滤(filter)操作[过滤话题,重映射,tf剪枝]

使用ROS rosbag工具进行过滤(filter)操作

文章目录

  • 使用ROS rosbag工具进行过滤(filter)操作
    • Introduction
    • Filtering topics
    • Using Python API for advanced filtering
    • Renaming and filtering topics simultaneously
    • Combining filtering, remapping, and transforming
    • Conclusion

[rosbag过滤话题,话题重映射,tf剪枝]

Introduction

在使用Robot Operating System (ROS)开发过程中,我们经常需要记录和回放传感器数据以进行调试和分析。rosbag是一个用于记录和回放ROS消息数据的工具。在某些情况下,我们可能只对某些特定的话题或消息感兴趣,或者希望对记录的数据进行修改以满足特定需求。本文将介绍如何使用rosbag API对记录的数据进行过滤操作。

Filtering topics

要过滤特定话题的消息,我们可以使用rosbag filter命令。例如,如果我们有一个包含多个话题的rosbag文件input.bag,但我们只对/odom和/imu话题感兴趣,我们可以执行以下命令:


rosbag filter input.bag output.bag "topic == '/odom' or topic == '/imu'"

这将创建一个名为output.bag的新rosbag文件,其中只包含/odom和/imu话题的消息。

Using Python API for advanced filtering

对于更复杂的过滤需求,我们可以使用rosbag的Python API。以下是一个示例脚本,该脚本将从输入的rosbag文件中读取数据,过滤出特定的话题,并将结果写入输出的rosbag文件:

#!/usr/bin/env python

import rosbag
import sys

def filter_bag(inbag, outbag, topics_to_keep):
    with rosbag.Bag(outbag, 'w') as outbag_handle:
        for topic, msg, t in rosbag.Bag(inbag).read_messages():
            if topic in topics_to_keep:
                outbag_handle.write(topic, msg, t)

if __name__ == "__main__":
    if len(sys.argv) < 4:
        print("Usage: filter_bag.py   ")
        sys.exit(1)

    inbag = sys.argv[1]
    outbag = sys.argv[2]
    topics_to_keep = sys.argv[3:]

    filter_bag(inbag, outbag, topics_to_keep)

Renaming and filtering topics simultaneously

在某些情况下,我们可能希望在过滤rosbag数据时对话题进行重命名。以下示例演示了如何在保留指定话题的同时将/scan_mark话题重命名为/scan:
filter_and_remap.py


import rospy
import rosbag
import sys

def filter_and_remap(inbag, outbag):
    topics_to_keep = ['/odom', '/raw_scan', '/scan_mark', '/tf', '/cmd_vel', '/heading']
    topic_remap = {'/scan_mark': '/scan'}

    with rosbag.Bag(outbag, 'w') as outbag_handle:
        for topic, msg, t in rosbag.Bag(inbag).read_messages():
            if topic in topics_to_keep:
                if topic in topic_remap:
                    outbag_handle.write(topic_remap[topic], msg, t)
                else:
                    outbag_handle.write(topic, msg, t)

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Usage: filter_and_remap.py  ")
        sys.exit(1)

    inbag = sys.argv[1]
    outbag = sys.argv[2]

    filter_and_remap(inbag, outbag)


./filter_and_remap.py xx.bag filtered_and_remapped.bag

这个脚本定义了一个名为filter_and_remap的函数,该函数读取输入的rosbag文件,保留指定的话题,并在写入输出的rosbag文件时重命名/scan_mark话题为/scan。
保存并关闭filter_and_remap.py。

Combining filtering, remapping, and transforming

我们还可以将过滤、重映射和转换操作组合在一起。以下示例演示了如何在保留指定话题的同时,将/scan_mark话题重命名为/scan并移除map -> odom转换:

#!/usr/bin/env python

import rospy
import rosbag
from tf2_msgs.msg import TFMessage
import sys

def filter_remap_remove_tf(inbag, outbag):
    topics_to_keep = ['/odom', '/raw_scan', '/scan_mark', '/tf', '/cmd_vel', '/heading']
    topic_remap = {'/scan_mark': '/scan'}

    with rosbag.Bag(outbag, 'w') as outbag_handle:
        for topic, msg, t in rosbag.Bag(inbag).read_messages():
            if topic in topics_to_keep:
                if topic == "/tf":
                    filtered_transforms = []
                    for transform in msg.transforms:
                        if not (transform.header.frame_id == "map" and transform.child_frame_id == "odom"):
                            filtered_transforms.append(transform)
                    msg.transforms = filtered_transforms
                    if len(filtered_transforms) > 0:
                        outbag_handle.write(topic, msg, t)
                else:
                    if topic in topic_remap:
                        outbag_handle.write(topic_remap[topic], msg, t)
                    else:
                        outbag_handle.write(topic, msg, t)

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Usage: filter_remap_remove_tf.py  ")
        sys.exit(1)
    inbag = sys.argv[1]
    outbag = sys.argv[2]

    filter_remap_remove_tf(inbag, outbag)

个脚本定义了一个名为filter_remap_remove_tf的函数,该函数读取输入的rosbag文件,保留指定的话题,重命名/scan_mark话题为/scan,并在写入输出的rosbag文件时移除map -> odom转换。
保存并关闭filter_remap_remove_tf.py。

./filter_remap_remove_tf.py xx.bag filtered_remap_remove_tf.bag

Conclusion

整体介绍了如何使用rosbag工具和Python API对ROS消息数据进行过滤操作

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