ROS 同时发布kitti数据集的图像和点云数据rviz显示，同时加载一个小车模型

  用ROS同时发布kitti数据集的图像和点云数据rviz显示，同时加载一个小车模型，效果如下：

1.准备数据

图像数据如下：

2.读取数据：data_utils.py

#!/usr/bin/env python

import cv2
import numpy as np

def read_camera(path):
    return cv2.imread(path)

def read_point_cloud(path):
    return np.fromfile(path,dtype=np.float32).reshap(-1,4)

3.发布数据：publish_utils.py

  定义了四个发布数据的函数：publish_camera、publish_pcl、publish_ego_car和publish_car_model，分别用于发布图像、点云、maker标记（图中的两条绿色的线）以及车辆模型（图中的小车模型）

#!/usr/bin/env python

from pyexpat import model
import rospy
from std_msgs.msg import Header
from sensor_msgs.msg import Image,PointCloud2
import sensor_msgs.point_cloud2 as pcl2
from cv_bridge import CvBridge
from visualization_msgs.msg import Marker
from geometry_msgs.msg import Point
import tf
import numpy as np
import tf_conversions

FRAME_ID='map'

def publish_camera(cam_pub,bridge,image):
    cam_pub.publish(bridge.cv2_to_imgmsg(image,'bgr8'))

def publish_pcl(pcl_pub,point_cloud):
    header=Header()
    header.stamp=rospy.Time.now()
    header.frame_id=FRAME_ID
    pcl_pub.publish(pcl2.create_cloud_xyz32(header,point_cloud[:,:3]))


def publish_ego_car(ego_car_pub):
    marker=Marker()
    marker.header.frame_id=FRAME_ID
    marker.header.stamp=rospy.Time.now()

    marker.id=0
    marker.action=Marker.ADD
    marker.lifetime=rospy.Duration()
    marker.type=Marker.LINE_STRIP

    marker.color.r=0.0
    marker.color.g=1.0
    marker.color.b=0.0
    marker.color.a=1.0
    marker.scale.x=0.2

    marker.points=[]
    marker.points.append(Point(10,10,0))
    marker.points.append(Point(0,0,0))
    marker.points.append(Point(10,-10,0))

    ego_car_pub.publish(marker)

def publish_car_model(model_pub):
    mesh_marker=Marker()
    mesh_marker.header.frame_id=FRAME_ID
    mesh_marker.header.stamp=rospy.Time.now()

    mesh_marker.id=-1
    mesh_marker.lifetime=rospy.Duration()
    mesh_marker.type=Marker.MESH_RESOURCE
    # mesh_marker.mesh_resource="package://kitti_tutorial/Audi R8/Models/Audi R8.dae"
    
    mesh_marker.mesh_resource="package://kitti_tutorial/Car-Model/Car.dae"

    mesh_marker.pose.position.x=0
    mesh_marker.pose.position.y=0
    mesh_marker.pose.position.z=-1.73
    q = tf_conversions.transformations.quaternion_from_euler(0,0,np.pi/2)
    mesh_marker.pose.orientation.x=q[0]
    mesh_marker.pose.orientation.y=q[1]
    mesh_marker.pose.orientation.z=q[2]
    mesh_marker.pose.orientation.w=q[3]

    mesh_marker.color.r=1.0
    mesh_marker.color.g=1.0
    mesh_marker.color.b=1.0
    mesh_marker.color.a=1.0

    mesh_marker.scale.x=0.9
    mesh_marker.scale.y=0.9
    mesh_marker.scale.z=0.9

    model_pub.publish(mesh_marker)

4.配置发布节点：KITTI.py

#!/usr/bin/env python
import os
from data_utils import *
from publish_utils import *

DATA_PATH='/home/chen/Downloads/kittidata/2011_09_26/2011_09_26_drive_0005_sync/'

if __name__=='__main__':
    rospy.init_node('kitti_node',anonymous=True)
    cam_pub=rospy.Publisher('kitti_cam',Image,queue_size=10)
    pcl_pub=rospy.Publisher('kitti_pcl',PointCloud2,queue_size=10)
    ego_pub=rospy.Publisher('kitti_ego_car',Marker,queue_size=10)
    model_pub=rospy.Publisher('kitti_car_model',Marker,queue_size=10)
    bridge=CvBridge()
    rate=rospy.Rate(10)
    frame=0

    while not rospy.is_shutdown():
        img=cv2.imread(os.path.join(DATA_PATH,'image_02/data/%010d.png'%frame))
        pcl=np.fromfile(os.path.join(DATA_PATH,'velodyne_points/data/%010d.bin'%frame),dtype=np.float32).reshape(-1,4)

        publish_camera(cam_pub,bridge,img)
        publish_pcl(pcl_pub,pcl)
        publish_ego_car(ego_pub)
        publish_car_model(model_pub)
        rospy.loginfo('published')
        rate.sleep()
        frame+=1
        frame%=154

5.下载小车模型dae

  google搜索car dae，从里面找免费的小车模型即可，需要找带有.dae后缀的模型，放到功能包下，在publish_utils.py的publish_car_model函数中修改路径: mesh_marker.mesh_resource="package://kitti_tutorial/Car-Model/Car.dae"，其中路径开头是package://，kitti_tutorial是我的功能包。

6.解决错误

  如果运行代码之后发现小车没有加载进来，并且rviz报错：Could not load resource [package://kitti_tutorial/Car_Model/Car.dae]: Unable to open file "package://kitti_tutorial/Car_Model/Car.dae".，这大概率是运行rviz的终端没有将环境变量添加进来，source一下就可以了。