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(工作小結之——ROS收發不同類型Message(二))
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2024-06-25 06:17:52【】4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!(8852)
相关文章
- 02 為什么tiktok沒有聲音(抖音合唱為什么沒有聲音)
- 01 youtube music pc download 64 bit windows安裝(如何在youtubemusic中創建快捷指令)
- 01 youtube music premium student price(今日新聞淺談:Youtube Music 也加入串流音樂服務大混戰)
- 02 中非貿易博覽會為什么在長沙(2019中非博覽會在長沙, 我們可以去看看嗎)
- 01 youtube music on 買粉絲s(中文歌在油管有版權嗎)
- 01 youtube music pc download 64 bits supported(如何在youtubemusic中創建快捷指令)
- 01 youtube music pc download index 買粉絲最強(如何讓YTmusic在后臺播放)
- 01 youtube music pc download 買粉絲 software download(如何在youtubemusic中創建快捷指令)
- 01 youtube music player for windows 10(2007年影響人類生活的十大IT產品)
- 02 中輕信達國際貿易有限公司(蘇州南京一代著名的外貿公司)
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:湖南张家界慈利县
工作室:小组
Email:[email protected]
热门文章
站长推荐
01 youtube music pc app設計說明怎么(備忘錄怎么轉到私密?)
01 youtube music pc download 買粉絲 software download(如何在youtubemusic中創建快捷指令)
02 中鋁海外控股有限公司(中鋁保險經紀(北京)股份有限公司 股東)
01 youtube music pc app下載安卓版(安卓4.0.3的操作系統是不是有兩種版本?)
01 youtube music pc download index 買粉絲最強(如何讓YTmusic在后臺播放)
01 youtube music premium 買粉絲 download中文永久(今日新聞淺談:Youtube Music 也加入串流音樂服務大混戰)
01 youtube music latest 2023(哪些音樂應用可以免費聽歌?)
01 youtube music pc app下載安裝電腦(今日新聞淺談:Youtube Music 也加入串流音樂服務大混戰)