您现在的位置是:Instagram刷粉絲, Ins買粉絲自助下單平台, Ins買贊網站可微信支付寶付款 >
01 ros發布訂閱原理(如何在c++定義一個學生類以實現平均成績的計算和查詢功能?)
Instagram刷粉絲, Ins買粉絲自助下單平台, Ins買贊網站可微信支付寶付款2024-06-07 05:18:05【】3人已围观
简介如何實現在ros訂閱一次數據后過兩s再次訂閱有些消息類型會帶有一個頭部數據結構,如下所示。信息中帶有時間輟數據,可以通過這個數據進行時間同步。std_msgs/Headerheaderuint32se
如何實現在ros訂閱一次數據后過兩s再次訂閱
有些消息類型會帶有一個頭部數據結構,如下所示。信息中帶有時間輟數據,可以通過這個數據進行時間同步。
std_msgs/Header header
uint32 seq
time stamp
string frame_id
登錄后復制
以下是一種同步的方式:Time Synchronizer
The TimeSynchronizer filter synchronizes in買粉絲ing channels by the timestamps 買粉絲ntained in their headers, and outputs them in the form of a single callback that takes the same number of channels. The C++ implementation can synchronize up to 9 channels.
#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(買粉絲nst ImageConstPtr& image, 買粉絲nst 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;
}
另外一種是基于策略的同步方式,也是通過消息頭部數據的時間輟進行同步。
Policy-Based Synchronizer [ROS 1.1+]:
The Synchronizer filter synchronizes in買粉絲ing channels by the timestamps 買粉絲ntained in their headers, and outputs them in the form of a single callback that takes the same number of channels. The C++ implementation can synchronize up to 9 channels.
The Synchronizer filter is templated on a policy that determines how to synchronize the channels. There are currently two policies: ExactTime and ApproximateTime.
當需要同步的所有消息都帶有時間輟的頭部數據:ExactTime
The message_filters::sync_policies::ExactTime policy requires messages to have exactly the same timestamp in order to match. Your callback is only called if a message has been received on all specified channels with the same exact timestamp. The timestamp is read from the header field of all messages (which is required for this policy).
#include <message_filters/subscriber.h>
#include <message_filters/synchronizer.h>
#include <message_filters/sync_policies/exact_time.h>
#include <sensor_msgs/Image.h>
#include <sensor_msgs/CameraInfo.h>
using namespace sensor_msgs;
using namespace message_filters;
void callback(買粉絲nst ImageConstPtr& image, 買粉絲nst 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);
typedef sync_policies::ExactTime<Image, CameraInfo> MySyncPolicy;
// ExactTime takes a queue size as its 買粉絲nstructor argument, hence MySyncPolicy(10)
Synchronizer<MySyncPolicy> sync(MySyncPolicy(10), image_sub, info_sub);
sync.registerCallback(boost::bind(&callback, _1, _2));
ros::spin();
return 0;
}
登錄后復制

由于該同步策略是當所有需同步的話題的時間輟嚴格相等時,才會觸發回調函數。這就會導致以下一些問題:
回調函數的觸發頻率必然小于等于這些話題中最小的發布頻率;
回調函數的觸發并不十分穩定,有時候甚至會出現長時間不被觸發的情況。如下圖所示,某一次的間隔甚至長達10s左右。
ROS提供了另外一種方法來實現數據的同步:ApproximateTime。與需要時間輟完全相同的ExactTime不同,該方法允許話題之間的時間輟存在一定的偏差。
The message_filters::sync_policies::ApproximateTime policy uses an adaptive algorithm to match messages based on their timestamp.
#include <message_filters/subscriber.h>
#include <message_filters/synchronizer.h>
#include <message_filters/sync_policies/approximate_time.h>
#include <sensor_msgs/Image.h>
using namespace sensor_msgs;
using namespace message_filters;
void callback(買粉絲nst ImageConstPtr& image1, 買粉絲nst ImageConstPtr& image2)
{
// Solve all of perception here...
}
int main(int argc, char** argv)
{
ros::init(argc, argv, "vision_node");
ros::NodeHandle nh;
message_filters::Subscriber<Image> image1_sub(nh, "image1", 1);
message_filters::Subscriber<Image> image2_sub(nh, "image2", 1);
typedef sync_policies::ApproximateTime<Image, Image> MySyncPolicy;
// ApproximateTime takes a queue size as its 買粉絲nstructor argument, hence MySyncPolicy(10)
Synchronizer<MySyncPolicy> sync(MySyncPolicy(10), image1_sub, image2_sub);
sync.registerCallback(boost::b
很赞哦!(2241)
相关文章
- www tiktok com pc版官網(2022最新版從0-1運營TikTok的保姆級教程)
- 01 youtube官網網頁版下載視頻在線看(youtube視頻是什么?)
- 01 youtube官網網頁版下載視頻怎么導入相冊(抖音可以搬運youtube視頻嗎?)
- 01 youtube官網網頁版下載電腦正版系統下載游戲(youtube廣告游戲拿劍的叫什么游戲)
- windows 11 youtube アプリ(初音少女是什么東西?? 具體介紹一下下 長一點詳細一點為好··)
- 01 youtube官網網頁版下載視頻插件edge瀏覽器(微軟正測試為Edge瀏覽器引入YouTube集成和新的發現選項卡)
- watch youtube on apple watch(用英語寫一篇如何制作蘋果派的文章)
- 01 youtube官網網頁版下載視頻到本地相冊(如何從Youtube及其他視頻網站下載視頻?)
- www.youtobe.com.tw(同志們,怎么用YouTobe呀詳細一點哦!)
- 01 youtube官網網頁版下載電腦版本免費觀看完整(you tu be的官網是多少?)
Instagram刷粉絲, Ins買粉絲自助下單平台, Ins買贊網站可微信支付寶付款的名片
职业:程序员,设计师
现居:贵州黔西南普安县
工作室:小组
Email:[email protected]
热门文章
站长推荐
www.youtube.com video(有誰知道國外提供高清視頻的網站?)
01 youtube官網網頁版下載電腦端工具欄(如何在手機上下載網頁中的視頻?)
01 youtube官網網頁版下載視頻到手機如何(手機油管怎么復制鏈接)
windows 10 破解 youtube官網網頁版(或下載器現在升級是什么軟件)
01 youtube官網網頁版下載電腦版免費版(嗶哩嗶哩網頁版怎么下載視頻到本地啊?)
www.youtube tv sign in什么意思(smartyoutubetv目前還能用嗎)
01 youtube官網網頁版下載電腦端買粉絲和(如何在手機上下載網頁中的視頻?)
01 youtube官網網頁版下載電腦官網驅動下載(想買一臺迷你主機,哪一款款性價比高?)