tf之 MessageFilter 与 tf::MessageFilter理解与应用
2024-06-01 21:47:14
Table of Contents
1 MessageFilter
1.1 主要用法之——消息的订阅与回调
1.2 主要用法之——时间同步
1.3 主要用法之——时间顺序的回调
2 tf::MessageFilter
2.1 示例AMCL
2.2 wiki教程
3 tf2_ros::MessageFilter
3.1 wiki教程
4 tf2_ros之使用tf进行坐标变换
4.1 tf::Transformer Class Reference
4.2 tf2_ros::BufferInterface Class Reference
references
1 MessageFilter
http://wiki.ros.org/message_filters
消息过滤器message_filters类似一个消息缓存，当消息到达消息过滤器的时候，可能并不会立即输出，而是在稍后的时间点里满足一定条件下输出。
举个例子，比如时间同步器，它接收来自多个源的不同类型的消息，并且仅当它们在具有相同时间戳的每个源上接收到消息时才输出它们，也就是起到了一个消息同步输出的效果。
1.1 主要用法之——消息的订阅与回调
message_filters::Subscriber<std_msgs::UInt32> sub(nh, "my_topic", 1);
sub.registerCallback(myCallback);
is the equivalent of:
ros::Subscriber sub = nh.subscribe("my_topic", 1, myCallback);
1.2 主要用法之——时间同步
TimeSynchronizer筛选器通过包含在其header中的时间戳同步进入的通道，并以采用相同数量通道的单个回调的形式输出它们。 C ++实现最多可以同步9个通道。
Example (C++)
Suppose you are writing a ROS node that needs to process data from two time synchronized topics. Your program will probably look something like this:
#include <message_filters/subscriber.h>
#include <message_filters/time_synchronizer.h>
#include <sensor_msgs/Image.h>
#include <sensor_msgs/CameraInfo.h>using namespace sensor_msgs;
using namespace message_filters;void callback(const ImageConstPtr& image, const CameraInfoConstPtr& cam_info)
{// Solve all of perception here...
}int main(int argc, char** argv)
{ros::init(argc, argv, "vision_node");ros::NodeHandle nh;message_filters::Subscriber<Image> image_sub(nh, "image", 1);message_filters::Subscriber<CameraInfo> info_sub(nh, "camera_info", 1);TimeSynchronizer<Image, CameraInfo> sync(image_sub, info_sub, 10);sync.registerCallback(boost::bind(&callback, _1, _2));ros::spin();return 0;
}
1.3 主要用法之——时间顺序的回调
TimeSequencer过滤器确保将根据消息头的时间戳按时间顺序调用消息。 TimeSequencer具有特定的延迟，该延迟指定了在传递消息之前将消息排队的时间。 在消息的时间戳少于指定的延迟之前，永远不会调用消息的回调。 但是，对于所有至少经过延迟才过时的消息，将调用它们的回调并保证其按时间顺序排列。 如果消息是在消息已调用回调之前的某个时间到达的，则会将其丢弃。
Example (C++)
C ++版本需要延迟和更新速率。 更新速率确定定序器将在其队列中检查准备通过的消息的频率。 最后一个参数是开始丢弃之前要排队的消息数。
message_filters::Subscriber<std_msgs::String> sub(nh, "my_topic", 1);
message_filters::TimeSequencer<std_msgs::String> seq(sub, ros::Duration(0.1), ros::Duration(0.01), 10);
seq.registerCallback(myCallback);2 tf::MessageFilter
tf::MessageFilter可以订阅任何的ROS消息，然后将其缓存，直到这些消息可以转换到目标坐标系，然后进行相应的处理（进入回调函数）。
tf::MessageFilter的初始化需要message_filters::Subscriber，tf转换，目标坐标系，等待时间。当message_filters::Subscriber的消息能够由tf转换到目标坐标系时，调用回调函数，回调函数由tf::MessageFilter::registerCallback()进行注册。
tf::MessageFilter< M > Class Template Reference:
http://docs.ros.org/diamondback/api/tf/html/c++/classtf_1_1MessageFilter.html
2.1 示例AMCL
tf_ = new TransformListenerWrapper();
message_filters::Subscriber<sensor_msgs::LaserScan>* laser_scan_sub_;
tf::MessageFilter<sensor_msgs::LaserScan>* laser_scan_filter_;laser_scan_sub_ = new message_filters::Subscriber<sensor_msgs::LaserScan>(nh_, scan_topic_, 100);
laser_scan_filter_ = new tf::MessageFilter<sensor_msgs::LaserScan>(*laser_scan_sub_, *tf_, odom_frame_id_, 100);laser_scan_filter_->registerCallback(boost::bind(&AmclNode::laserReceived, this, _1));void AmclNode::laserReceived(const sensor_msgs::LaserScanConstPtr& laser_scan){this->tf_->transformPose(base_frame_id_, ident, laser_pose);//这个函数的意思是，ident在base_frame_id下的表示为laser_pose
}
2.2 wiki教程
http://wiki.ros.org/tf/Tutorials/Using%20Stamped%20datatypes%20with%20tf%3A%3AMessageFilter
#include "ros/ros.h"
#include "tf/transform_listener.h"
#include "tf/message_filter.h"
#include "message_filters/subscriber.h"class PoseDrawer
{
public:PoseDrawer() : tf_(), target_frame_("turtle1"){point_sub_.subscribe(n_, "turtle_point_stamped", 10);tf_filter_ = new tf::MessageFilter<geometry_msgs::PointStamped>(point_sub_, tf_, target_frame_, 10);tf_filter_->registerCallback( boost::bind(&PoseDrawer::msgCallback, this, _1) );} ;private:message_filters::Subscriber<geometry_msgs::PointStamped> point_sub_;tf::TransformListener tf_;tf::MessageFilter<geometry_msgs::PointStamped> * tf_filter_;ros::NodeHandle n_;std::string target_frame_;// Callback to register with tf::MessageFilter to be called when transforms are availablevoid msgCallback(const boost::shared_ptr<const geometry_msgs::PointStamped>& point_ptr) {geometry_msgs::PointStamped point_out;try {tf_.transformPoint(target_frame_, *point_ptr, point_out);printf("point of turtle 3 in frame of turtle 1 Position(x:%f y:%f z:%f)\n", point_out.point.x,point_out.point.y,point_out.point.z);}catch (tf::TransformException &ex) {printf ("Failure %s\n", ex.what()); //Print exception which was caught}};};int main(int argc, char ** argv)
{ros::init(argc, argv, "pose_drawer"); //Init ROSPoseDrawer pd; //Construct classros::spin(); // Run until interupted
};3 tf2_ros::MessageFilter
3.1 wiki教程
http://wiki.ros.org/tf2/Tutorials/Using%20stamped%20datatypes%20with%20tf2%3A%3AMessageFilter
#include "ros/ros.h"
#include "geometry_msgs/PointStamped.h"#include "tf2_ros/transform_listener.h"
#include "tf2_ros/message_filter.h"
#include "message_filters/subscriber.h"
#include "tf2_geometry_msgs/tf2_geometry_msgs.h"class PoseDrawer
{
public:PoseDrawer() :tf2_(buffer_), target_frame_("turtle1"),tf2_filter_(point_sub_, buffer_, target_frame_, 10, 0){point_sub_.subscribe(n_, "turtle_point_stamped", 10);tf2_filter_.registerCallback( boost::bind(&PoseDrawer::msgCallback, this, _1) );}// Callback to register with tf2_ros::MessageFilter to be called when transforms are availablevoid msgCallback(const geometry_msgs::PointStampedConstPtr& point_ptr) {geometry_msgs::PointStamped point_out;try {buffer_.transform(*point_ptr, point_out, target_frame_);ROS_INFO("point of turtle 3 in frame of turtle 1 Position(x:%f y:%f z:%f)\n", point_out.point.x,point_out.point.y,point_out.point.z);}catch (tf2::TransformException &ex) {ROS_WARN("Failure %s\n", ex.what()); //Print exception which was caught}}private:std::string target_frame_;tf2_ros::Buffer buffer_;tf2_ros::TransformListener tf2_;ros::NodeHandle n_;message_filters::Subscriber<geometry_msgs::PointStamped> point_sub_;tf2_ros::MessageFilter<geometry_msgs::PointStamped> tf2_filter_;};int main(int argc, char ** argv)
{ros::init(argc, argv, "pose_drawer"); //Init ROSPoseDrawer pd; //Construct classros::spin(); // Run until interupted return 0;
};
tf2_ros::TransformListener 通过 tf2_(buffer_) 对 tf2_ros::Buffer 进行初始化。4 tf2_ros之使用tf进行坐标变换
4.1 tf::Transformer Class Reference
|
Public Member Functions |
|
| boost::signals2::connection | addTransformsChangedListener (boost::function< void(void)> callback) |
| Add a callback that happens when a new transform has arrived. | |
| std::string | allFramesAsDot (double current_time=0) const |
| A way to see what frames have been cached Useful for debugging. | |
| std::string | allFramesAsString () const |
| A way to see what frames have been cached Useful for debugging. | |
| bool | canTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, std::string *error_msg=NULL) const |
| Test if a transform is possible. | |
| bool | canTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, std::string *error_msg=NULL) const |
| Test if a transform is possible. | |
| void | chainAsVector (const std::string &target_frame, ros::Time target_time, const std::string &source_frame, ros::Time source_time, const std::string &fixed_frame, std::vector< std::string > &output) const |
| Debugging function that will print the spanning chain of transforms. Possible exceptions tf::LookupException, tf::ConnectivityException, tf::MaxDepthException. | |
| void | clear () |
| Clear all data. | |
| bool | frameExists (const std::string &frame_id_str) const |
| Check if a frame exists in the tree. | |
| ros::Duration | getCacheLength () |
| Get the duration over which this transformer will cache. | |
| void | getFrameStrings (std::vector< std::string > &ids) const |
| A way to get a std::vector of available frame ids. | |
| int | getLatestCommonTime (const std::string &source_frame, const std::string &target_frame, ros::Time &time, std::string *error_string) const |
| Return the latest rostime which is common across the spanning set zero if fails to cross. | |
| bool | getParent (const std::string &frame_id, ros::Time time, std::string &parent) const |
| Fill the parent of a frame. | |
| std::string | getTFPrefix () const |
| Get the tf_prefix this is running with. | |
| bool | isUsingDedicatedThread () |
| void | lookupTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, StampedTransform &transform) const |
| Get the transform between two frames by frame ID. | |
| void | lookupTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, StampedTransform &transform) const |
| Get the transform between two frames by frame ID assuming fixed frame. | |
| void | lookupTwist (const std::string &tracking_frame, const std::string &observation_frame, const std::string &reference_frame, const tf::Point &reference_point, const std::string &reference_point_frame, const ros::Time &time, const ros::Duration &averaging_interval, geometry_msgs::Twist &twist) const |
| Lookup the twist of the tracking_frame with respect to the observation frame in the reference_frame using the reference point. | |
| void | lookupTwist (const std::string &tracking_frame, const std::string &observation_frame, const ros::Time &time, const ros::Duration &averaging_interval, geometry_msgs::Twist &twist) const |
| lookup the twist of the tracking frame with respect to the observational frame | |
| void | removeTransformsChangedListener (boost::signals2::connection c) |
| void | setExtrapolationLimit (const ros::Duration &distance) |
| Set the distance which tf is allow to extrapolate. | |
| bool | setTransform (const StampedTransform &transform, const std::string &authority="default_authority") |
| Add transform information to the tf data structure. | |
| void | setUsingDedicatedThread (bool value) |
| Transformer (bool interpolating=true, ros::Duration cache_time_=ros::Duration(DEFAULT_CACHE_TIME)) | |
| void | transformPoint (const std::string &target_frame, const Stamped< tf::Point > &stamped_in, Stamped< tf::Point > &stamped_out) const |
| Transform a Stamped Point into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformPoint (const std::string &target_frame, const ros::Time &target_time, const Stamped< tf::Point > &stamped_in, const std::string &fixed_frame, Stamped< tf::Point > &stamped_out) const |
| Transform a Stamped Point into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformPose (const std::string &target_frame, const Stamped< tf::Pose > &stamped_in, Stamped< tf::Pose > &stamped_out) const |
| Transform a Stamped Pose into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformPose (const std::string &target_frame, const ros::Time &target_time, const Stamped< tf::Pose > &stamped_in, const std::string &fixed_frame, Stamped< tf::Pose > &stamped_out) const |
| Transform a Stamped Pose into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformQuaternion (const std::string &target_frame, const Stamped< tf::Quaternion > &stamped_in, Stamped< tf::Quaternion > &stamped_out) const |
| Transform a Stamped Quaternion into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformQuaternion (const std::string &target_frame, const ros::Time &target_time, const Stamped< tf::Quaternion > &stamped_in, const std::string &fixed_frame, Stamped< tf::Quaternion > &stamped_out) const |
| Transform a Stamped Quaternion into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformVector (const std::string &target_frame, const Stamped< tf::Vector3 > &stamped_in, Stamped< tf::Vector3 > &stamped_out) const |
| Transform a Stamped Vector3 into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| void | transformVector (const std::string &target_frame, const ros::Time &target_time, const Stamped< tf::Vector3 > &stamped_in, const std::string &fixed_frame, Stamped< tf::Vector3 > &stamped_out) const |
| Transform a Stamped Vector3 into the target frame This can throw anything a lookupTransform can throw as well as tf::InvalidArgument. | |
| bool | waitForTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, const ros::Duration &timeout, const ros::Duration&polling_sleep_duration=ros::Duration(0.01), std::string *error_msg=NULL) const |
| Block until a transform is possible or it times out. | |
| bool | waitForTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, const ros::Duration &timeout, const ros::Duration &polling_sleep_duration=ros::Duration(0.01), std::string *error_msg=NULL) const |
| Block until a transform is possible or it times out. | |
| virtual | ~Transformer (void) |
4.2 tf2_ros::BufferInterface Class Reference
tf2_ros::Buffer::transform() 可以直接将一个坐标系下的位姿转换到另一个坐标系的位姿。
tf2_ros::Buffer Class Reference: http://docs.ros.org/melodic/api/tf2_ros/html/c++/classtf2__ros_1_1Buffer.html
buffer_interface.h File Reference: http://docs.ros.org/jade/api/tf2_ros/html/c++/buffer__interface_8h.html
tf2_ros::BufferInterface Class Reference: http://docs.ros.org/jade/api/tf2_ros/html/c++/classtf2__ros_1_1BufferInterface.html
| virtual bool | canTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, const ros::Duration timeout, std::string *errstr=NULL) const =0 |
| Test if a transform is possible. | |
| virtual bool | canTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, const ros::Duration timeout, std::string *errstr=NULL) const =0 |
| Test if a transform is possible. | |
|
virtual geometry_msgs::TransformStamped |
lookupTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, const ros::Duration timeout) const =0 |
| Get the transform between two frames by frame ID. | |
|
virtual geometry_msgs::TransformStamped |
lookupTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, const ros::Duration timeout) const =0 |
| Get the transform between two frames by frame ID assuming fixed frame. | |
| template<class T > | |
| T & | transform (const T &in, T &out, const std::string &target_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame. This function is templated and can take as input any valid mathematical object that tf knows how to apply a transform to, by way of the templated math conversions interface. For example, the template type could be a Transform, Pose, Vector, or Quaternion message type (as defined in geometry_msgs). | |
| template<class T > | |
| T | transform (const T &in, const std::string &target_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame. This function is templated and can take as input any valid mathematical object that tf knows how to apply a transform to, by way of the templated math conversions interface. For example, the template type could be a Transform, Pose, Vector, or Quaternion message type (as defined in geometry_msgs). | |
| template<class A , class B > | |
| B & | transform (const A &in, B &out, const std::string &target_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame and convert to a specified output type. It is templated on two types: the type of the input object and the type of the transformed output. For example, the template types could be Transform, Pose, Vector, or Quaternion messages type (as defined in geometry_msgs). The function will calculate the transformation and then convert the result into the specified output type. Compilation will fail if a known conversion does not exist bewteen the two template parameters. | |
| template<class T > | |
| T & | transform (const T &in, T &out, const std::string &target_frame, const ros::Time &target_time, const std::string &fixed_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame (advanced). This function is templated and can take as input any valid mathematical object that tf knows how to apply a transform to, by way of the templated math conversions interface. For example, the template type could be a Transform, Pose, Vector, or Quaternion message type (as defined in geometry_msgs). This function follows the advanced API, which allows transforming between different time points, and specifying a fixed frame that does not varying in time. | |
| template<class T > | |
| T | transform (const T &in, const std::string &target_frame, const ros::Time &target_time, const std::string &fixed_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame (advanced). This function is templated and can take as input any valid mathematical object that tf knows how to apply a transform to, by way of the templated math conversions interface. For example, the template type could be a Transform, Pose, Vector, or Quaternion message type (as defined in geometry_msgs). This function follows the advanced API, which allows transforming between different time points, and specifying a fixed frame that does not varying in time. | |
| template<class A , class B > | |
| B & | transform (const A &in, B &out, const std::string &target_frame, const ros::Time &target_time, const std::string &fixed_frame, ros::Duration timeout=ros::Duration(0.0)) const |
| Transform an input into the target frame and convert to a specified output type (advanced). It is templated on two types: the type of the input object and the type of the transformed output. For example, the template type could be a Transform, Pose, Vector, or Quaternion message type (as defined in geometry_msgs). The function will calculate the transformation and then convert the result into the specified output type. Compilation will fail if a known conversion does not exist bewteen the two template parameters. This function follows the advanced API, which allows transforming between different time points, and specifying a fixed frame that does not varying in time. | |
references
1. https://blog.csdn.net/u013834525/article/details/80222686
tf之 MessageFilter 与 tf::MessageFilter理解与应用相关推荐
- tf第八讲：global_step理解与指数衰减学习率
大家好,我是爱编程的喵喵.双985硕士毕业,现担任全栈工程师一职,热衷于将数据思维应用到工作与生活中.从事机器学习以及相关的前后端开发工作.曾在阿里云.科大讯飞.CCF等比赛获得多次Top名次.现 ...
- tf.app.flags和tf.app.run的使用
tf.app.flags和tf.app.run的使用 tf.app.flags主要用于处理命令行参数的解析工作,其实可以理解为一个封装好了的argparse包(argparse是一种结构化的数据存储格 ...
- tf.nn.conv2d和tf.contrib.slim.conv2d的区别
转自:http://blog.sina.com.cn/s/blog_6ca0f5eb0102wsuu.html 文中摘要: " 在上述的API中,可以看出去除掉初始化的部分,那么两者并没有什 ...
- TensorFlow学习——tf.nn.conv2d和tf.contrib.slim.conv2d的区别
在查看代码的时候,看到有代码用到卷积层是tf.nn.conv2d,也有的使用的卷积层是tf.contrib.slim.conv2d,这两个函数调用的卷积层是否一致,在查看了API的文档,以及slim. ...
- tf第四讲：tf中的循环tf.while_loop，条件tf.cond，比较、数学运算、类型转换
大家好,我是爱编程的喵喵.双985硕士毕业,现担任全栈工程师一职,热衷于将数据思维应用到工作与生活中.从事机器学习以及相关的前后端开发工作.曾在阿里云.科大讯飞.CCF等比赛获得多次Top名次.现 ...
- tf.reduce_prod用法及tf.placehoder用法
''' tf.reduce_prod(input_tensor,axis=None,keepdims=None,name=None,reduction_indices=None,keep_dims=N ...
- 关于学习tf.random.normal()和tf.random.uniform()的一点小总结
tf.random.normal(shape,mean=0.0,stddev=1.0)-正态分布 1.shape-可以创建形状为shape的数组 2.mean-均值 3.stddev-标准差,正态分布 ...
- tf.nn.softmax_cross_entropy_with_logits 和 tf.contrib.legacy_seq2seq.sequence_loss_by_example 的联系与区别
文章目录 0.函数介绍 1.区别联系 1.1 tf.nn.softmax_cross_entropy_with_logits 1.2 tf.nn.sparse_softmax_cross_entrop ...
- tf.dynamic_stitch 和 tf.dynamic_partition
import tensorflow as tf x=tf.constant([0.1, -1., 5.2, 4.3, -1., 7.4])#判断x里面的元素是否是1 condition_mask=tf ...
- TF之RNN：TF的RNN中的常用的两种定义scope的方式get_variable和Variable
TF之RNN:TF的RNN中的常用的两种定义scope的方式get_variable和Variable 目录 输出结果 代码设计 输出结果 代码设计 # tensorflow中的两种定义scope(命 ...
最新文章
- 左牵Uber右联大众，黄教主带领320家车企一统自动驾驶江湖
- CentOS使用yum安装Docker
- ashx PHP文件 优劣,.NET_后缀为 ashx 与 axd 的文件区别浅析，唯一不同的地方是：axd扩展名 - phpStudy...
- [WCF权限控制]利用WCF自定义授权模式提供当前Principal[实例篇]
- Java中关于String类型的10个问题
- Eureka 简介和使用
- java程序员面试需要注意什么_Java程序员面试时要注意的一些问题
- k8s包管理器helm_K8S 实战（十九）| K8S 包管理 Helm
- mysql 额外内存池_MySQL探秘(三):InnoDB的内存结构和特性
- 头脑仅仅是一个实验室
- leetcode 【 Sort Colors 】python 实现
- oracle12兼容ojdbc6,oracle ojdbc6 使用 报错
- 新能源充电桩后台管理系统平台
- 安川ga700变频器故障码集_安川变频器GA700参数设定出错解决方法
- 软件性能测试包括哪些方面,简述软件系统性能指标主要包括哪些方面
- 17-内部类的基本概念
- 【C++】C++中头文件使用双引号与书名号的区别
- win7c盘空间越来越小_你Windows10的C盘究竟多大才合适
- 【软件测试】PDM、PTM、IPD介绍（捣鼓一晚上的血泪知识）
- 004永磁同步电机的工作原理：大白话详细讲解从最简单的直流有刷电机到永磁同步电机是如何转动起来的