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訂閱不到消息(ROS訂閱的topic如何通過tcp傳送給QT并顯示到界面上)
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2024-06-01 07:56:16【】9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!(836)
相关文章
- 08 網織紅細胞計數3.11(富馬酸鐵簡介)
- 01 facebook看不到對方在線時間是不是拉黑了(facebook我被對方拉黑以后是不是不能繼續搜索對方賬號了?)
- 01 facebook蘋果手機視頻下載器(Facebook的視頻怎么保存到手機)
- 01 facebook賬號和ins賬號是一樣的嗎(facebook和instagram賬號密碼一樣嗎)
- 08 蘋果手機rss訂閱軟件哪個好(在一些閱讀器里將書架入書架上閱讀,要不要錢???)
- 01 facebook被對方屏蔽了(facebook如何取消對一個人的屏蔽)
- 01 facebook賬號被盜了怎么辦(我的手機號碼被黑客監控監聽了怎么辦?)
- 01 facebook經過復審后不通過(facebook被停用已經復審不撤銷怎么辦)
- 01 facebook營銷推廣軟件(如何在海外推廣App)
- 08 融資性貿易案例通報(銀行貸款融資案例)
热门文章
站长推荐
01 facebook電影社交網絡(電影《社交網絡》講的是什么?)
08 解決國際貿易爭議中被廣泛采用的方式(國際慣例有哪些)
08 網織紅細胞生成指數為一最可能診斷是慢性失血性貧血(貧血可以飲酒嗎)
08 網紅經濟作文200字(廣安網紅旅游景點介紹 廣安網紅旅游景點介紹作文)
08 蘇區建設中對外貿易是對哪個(為什么九江一直是江西第二大城市,而贛州不是?)
08 西班牙外海島嶼的名稱及所在海洋(為什么世界上的考古學家,對亞特蘭提斯如此向往為什么要花費無數精力,都要尋找到它)
08 營口金橋國際貿易有限公司(共同訴訟的法律規定是怎樣的)
08 綜合教程上海外語教育出版社第三版(全新版大學進階英語綜合教程(1)課后習題答案 上海外語教育出版社出版)