ROS链接openni库获取kinect数据（PC端）

        ROS库中本身带有kinect的驱动和应用包，但是很难应用到嵌入式系统当中，但是单独的openni库已经很完善了，很容易应用在PC机和嵌入式系统当中。为了在嵌入式的ARM系统中应用ROS和kinect，首先我在PC机上进行ROS链接openni库的实验。

       一、安装openni库

       参考链接：http://www.20papercups.net/programming/kinect-on-ubuntu-with-openni/

            

       二、建立kinect_test包

       首先建立一个ROS的package，然后在src文件夹下建立代码文件，结合ROS教程中WritingPublisherSubscriber（C++）一章中的编程方法和openni中samples里的NiSimpleRead例程代码，使用openni库中的功能函数获取kinect数据，并使用ROS进行消息发布。代码如下（代码包下载请见http://download.csdn.net/detail/hcx25909/5093853）：

        1、kinect_value_talker.cpp

/****************************************************************************
*                                                                           *
*  OpenNI 1.x Alpha                                                         *
*  Copyright (C) 2011 PrimeSense Ltd.                                       *
*                                                                           *
*  This file is part of OpenNI.                                             *
*                                                                           *
*  OpenNI is free software: you can redistribute it and/or modify           *
*  it under the terms of the GNU Lesser General Public License as published *
*  by the Free Software Foundation, either version 3 of the License, or     *
*  (at your option) any later version.                                      *
*                                                                           *
*  OpenNI is distributed in the hope that it will be useful,                *
*  but WITHOUT ANY WARRANTY; without even the implied warranty of           *
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the             *
*  GNU Lesser General Public License for more details.                      *
*                                                                           *
*  You should have received a copy of the GNU Lesser General Public License *
*  along with OpenNI. If not, see <http://www.gnu.org/licenses/>.           *
*                                                                           *
****************************************************************************/
//---------------------------------------------------------------------------
// Includes
//---------------------------------------------------------------------------
#include <XnOpenNI.h>
#include <XnLog.h>
#include <XnCppWrapper.h>
#include <XnFPSCalculator.h>

#include "ros/ros.h"
#include "std_msgs/String.h"

#include <sstream>

//---------------------------------------------------------------------------
// Defines
//---------------------------------------------------------------------------
#define SAMPLE_XML_PATH "Data/SamplesConfig.xml"

//---------------------------------------------------------------------------
// Macros
//---------------------------------------------------------------------------
#define CHECK_RC(rc, what)											\
	if (rc != XN_STATUS_OK)											\
	{																\
		printf("%s failed: %s\n", what, xnGetStatusString(rc));		\
		return rc;													\
	}

//---------------------------------------------------------------------------
// Code
//---------------------------------------------------------------------------
using namespace xn;

XnBool fileExists(const char *fn)
{
	XnBool exists;
	xnOSDoesFileExist(fn, &exists);
	return exists;
}

int main(int argc, char **argv)
{
    XnStatus nRetVal = XN_STATUS_OK;

	Context context;
	ScriptNode scriptNode;
	EnumerationErrors errors;

    ros::init(argc, argv, "talker");
    ros::NodeHandle n;
    ros::Publisher chatter_pub = n.advertise<std_msgs::String>("kinect_value", 1000);
    ros::Rate loop_rate(10);

	const char *fn = NULL;

    if	(fileExists(SAMPLE_XML_PATH)) fn = SAMPLE_XML_PATH;
	else {
		printf("Could not find '%s'. Aborting.\n" , SAMPLE_XML_PATH);
		return XN_STATUS_ERROR;
	}
	printf("Reading config from: '%s'\n", fn);

    nRetVal = context.InitFromXmlFile(fn, scriptNode, &errors);

	if (nRetVal == XN_STATUS_NO_NODE_PRESENT)
	{
		XnChar strError[1024];
		errors.ToString(strError, 1024);
		printf("%s\n", strError);
		return (nRetVal);
	}
	else if (nRetVal != XN_STATUS_OK)
	{
		printf("Open failed: %s\n", xnGetStatusString(nRetVal));
		return (nRetVal);
	}

	DepthGenerator depth;
	nRetVal = context.FindExistingNode(XN_NODE_TYPE_DEPTH, depth);
	CHECK_RC(nRetVal, "Find depth generator");

	XnFPSData xnFPS;
	nRetVal = xnFPSInit(&xnFPS, 180);
	CHECK_RC(nRetVal, "FPS Init");

	DepthMetaData depthMD;
  
    while ((!xnOSWasKeyboardHit()) && (ros::ok()))
	{
        std_msgs::String msg;
        std::stringstream ss;

		nRetVal = context.WaitOneUpdateAll(depth);
		if (nRetVal != XN_STATUS_OK)
		{
			printf("UpdateData failed: %s\n", xnGetStatusString(nRetVal));
			continue;
		}

		xnFPSMarkFrame(&xnFPS);

		depth.GetMetaData(depthMD);
		const XnDepthPixel* pDepthMap = depthMD.Data();

        ss << "Frame " << depthMD.FrameID();
        ss << "  Middle point is: " <<  depthMD(depthMD.XRes() / 2, depthMD.YRes() / 2);
        ss << "  FPS: " << xnFPSCalc(&xnFPS);
        msg.data = ss.str();

        ROS_INFO("%s", msg.data.c_str());

        chatter_pub.publish(msg);

        ros::spinOnce();
        loop_rate.sleep();
	}

	depth.Release();
	scriptNode.Release();
	context.Release();

	return 0;
}

       2、 kinect_value_listener.cpp

#include "ros/ros.h"
#include "std_msgs/String.h"

/**
 * This tutorial demonstrates simple receipt of messages over the ROS system.
 */
void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
  ROS_INFO("I heard: [%s]", msg->data.c_str());
}

int main(int argc, char **argv)
{
  ros::init(argc, argv, "listener");
  ros::NodeHandle n;

  ros::Subscriber sub = n.subscribe("kinect_value", 1000, chatterCallback);

  ros::spin();

  return 0;
}

       参考链接：http://www.ros.org/wiki/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29

            

       三、修改编译文件

       首先在CMakeLists.txt中将程序和openni库进行链接。在文件中加入头文件路径：

include_directories ("/usr/include/ni/")

       加入编译的文件和链接的库：

rosbuild_add_executable(kinect_value_talker   src/kinect_value_talker.cpp)
rosbuild_add_executable(kinect_value_listener src/kinect_value_listener.cpp)
target_link_libraries(kinect_value_talker OpenNI)     

        然后进行rosmake编译。

        实验结果：

        参考链接：http://www.ros.org/wiki/openni

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