ONI文件生成与读取

之前一直不知道如何实时保存RGB-D数据，每次都写入PCD文件不现实，对于30fps的，每秒就有30个PCD文件，硬盘速度绝逼跟不上。保存color和depth视频吧，总觉得不方便，而且depth压缩与解压缩会有精度损失。

后来老外提醒我：

/OpenNI2/Source/Tools/NiViewer    press s to record oni file

感觉很方便，于是自己参考了《openni cookbook》，开始罗代码了。没有解释，有 问题自己看那本书吧。

生成含有RBG-D的ONI文件：

#include <OpenNI.h>
#include <stdio.h>
using namespace openni;
char ReadLastCharOfLine()
{
	int newChar = 0;
	int lastChar;

	fflush(stdout);

	do
	{
		lastChar = newChar;
		newChar = getchar();
	}while ((newChar != '\n')&& (newChar != EOF));

	return (char)lastChar;
}
bool HandleStatus(Status status)
{
	if (status == STATUS_OK)
		return true;
	printf("ERROR: #%d, %s", status,OpenNI::getExtendedError());
	ReadLastCharOfLine();
	return false;
}

int main()
{
	Status status = STATUS_OK;
	printf("Scanning machine for devices and loading " "modules/drivers ...\r\n");
    status = OpenNI::initialize();
    if (!HandleStatus(status))
		return 1;
    printf("Completed.\r\n");
	Device device;
	printf("Opening first device ...\r\n");

	status = device.open(ANY_DEVICE);
	if (!HandleStatus(status))
		return 1;
	printf("%s Opened, Completed.\r\n",
	device.getDeviceInfo().getName());
	printf("Checking if stream is supported ...\r\n");
	if (!device.hasSensor(SENSOR_DEPTH))
	{
		printf("Stream not supported by this device.\r\n");
		return 1;
	}
	printf("Asking device to create a depth stream ...\r\n");

	VideoStream depthSensor;
	VideoStream colorSensor;

	status = depthSensor.create(device, SENSOR_DEPTH);
	if (!HandleStatus(status))
		return 1;

	status = colorSensor.create(device, SENSOR_COLOR);
	if (!HandleStatus(status))
		return 1;
	printf("Starting stream ...\r\n");

	status = depthSensor.start();
	if (!HandleStatus(status))
		return 1;
	status = colorSensor.start();
	if (!HandleStatus(status))
		return 1;
	printf("Done.\r\n");
	printf("Creating a recorder ...\r\n");

	Recorder recorder;
	status = recorder.create("sample.oni");
	if (!HandleStatus(status))
		return 1;
	printf("Done.\r\n");
	printf("Attaching to depth sensor ...\r\n");
	status = recorder.attach(depthSensor);
	if (!HandleStatus(status))
		return 1;
        status = recorder.attach(colorSensor);
	if (!HandleStatus(status))
		return 1;
	printf("Done.\r\n");
	printf("Starting recorder ...\r\n");
	status = recorder.start();
	if (!HandleStatus(status))
		return 1;
	printf("Done. Now recording ...\r\n");

	ReadLastCharOfLine();
	recorder.destroy();
	depthSensor.destroy();
	colorSensor.destroy();
	device.close();
	OpenNI::shutdown();
	return 0;
}

读取上述ONI文件的RGB信息，并保存到PNG文件【代码是转载的，如果要读取深度信息，再加个 openni::SENSOR_DEPTH分支就行了】

#include <iostream>
#include <OpenNI.h>
#include <opencv2/photo.hpp>
#include <opencv2/highgui.hpp>  

using namespace std;  

int main()
{
    //定义oni文件中视频的总帧数以及得到的图片的保存目录
    int total = 0;
    char* imagefile = "/home/jst/Data";  

    //初始化OpenNI环境
    openni::OpenNI::initialize();  

    //声明设备并打开oni文件
    openni::Device fromonifile;
    fromonifile.open("sample.oni");  

    //声明控制对象，这对视频流的控制起到了关键作用
    openni::PlaybackControl* pController = fromonifile.getPlaybackControl();  

    //声明视频流对象以及帧对象
    openni::VideoStream streamColor;
    openni::VideoFrameRef frameColor;  

    //验证是否有彩色传感器（是否有彩色视频）和建立与设备想关联的视频流
    if(fromonifile.hasSensor(openni::SENSOR_COLOR))
    {
        if(streamColor.create( fromonifile, openni::SENSOR_COLOR ) == openni::STATUS_OK )
        {
            cout<<"建立视频流成功"<<endl;
        }
        else
        {
            cerr<<"ERROR: 建立视频流没有成功"<<endl;
            system("pause");
            return -1;
        }
    }
    else
    {
        cerr << "ERROR: 该设备没有彩色传感器" << endl;
        system("pause");
        return -1;
    }  

    //建立显示窗口
    cv::namedWindow("Image");  

    //获取总的视频帧数并将该设备的速度设为-1以便能留出足够的时间对每一帧进行处理、显示和保存
    total = pController->getNumberOfFrames(streamColor);
    pController->setSpeed(-1);  

    //开启视频流
    streamColor.start();
    for (int i = 1;i <= total; ++ i)
    {
        //读取视频流的当前帧
        streamColor.readFrame(&frameColor);  

        cout<<"当前正在读的帧数是："<<frameColor.getFrameIndex()<<endl;
        cout<<"当前的循环次数是：  "<<i<<endl;  

        //将帧保存到Mat中并且将其转换到BGR模式，因为在OpenCV中图片的模式是BGR
        cv::Mat rgbImg(frameColor.getHeight(), frameColor.getWidth(), CV_8UC3, (void*)frameColor.getData());
        cv::Mat bgrImg;
        cvtColor(rgbImg, bgrImg, CV_RGB2BGR);  

        //将每一帧按顺序帧保存到图片目录下
        char imagefullname[255];
        char imagenum[50];
        sprintf(imagenum,"/%03d.png",i);
        strcpy(imagefullname,imagefile);
        strcat(imagefullname,imagenum);
        cv::imwrite(imagefullname,bgrImg);  

        //显示当前帧
        cv::imshow("Image",bgrImg);
        if (cv::waitKey(30) == 27)
        {
            break;
        }
    }  

    //销毁显示窗口
    cv::destroyWindow("Image");   

    //关闭视频流
    streamColor.destroy();  

    //关闭设备
    fromonifile.close();  

    //关闭OpenNI
    openni::OpenNI::shutdown();  

    return 0;
}