Kinect+OpenNI学习笔记之8(Robert Walter手部提取代码的分析)

 

　　前言

　　一般情况下,手势识别的第一步就是先手势定位,即手势所在部位的提取。本文是基于kinect来提取手势识别的，即先通过kinect找出人体的轮廓，然后定位轮廓中与手部有关的点，在该点的周围提取出满足一定要求的区域，对该区域进行滤波后得到的区域就是手部了。然后利用凸包和凹陷的数学几何方法，画出手指和手指凹陷处的点，以及手的轮廓线，并在图像中显示出来。文章所有代码都是网友Robert Walter提供的，它的代码下载网站为：http://dl.dropbox.com/u/5505209/FingertipTuio3d.zip

　　本人因为要做这方面的研究，所有本文只是读了他的代码，并稍加分析了下。

　　开发环境：OpenNI+OpenCV

 

　实验说明

　　手势定位和提取功能的实现主要是依靠OpenNI和OpenCV的实现，定位部分依靠OpenNI的人体骨架跟踪功能，手部的提取依靠OpenCV中一些与轮廓有关的函数。整个实验的流程图如下：

　　

 

　　手部提取时用到的几个OpenCV函数解释如下：

　　void convexHull(InputArray points, OutputArray hull, bool clockwise=false, bool returnPoints=true )

　　该函数的作用是找到输入点集points的凸包集合，参数1为输入的点集；参数2为是与输出凸包集合有关的，它是一个向量，如果向量元素的类型为整型，则表示其为凸包集合的点在原始输入集合点的下标索引，如果向量的数据类型为Point型，则表示其为凸包的点集；参数3表示输出凸包集合的方向，为true时表示顺时针方向输出；参数4表示是否输出凸包的集合中的点坐标，这个只有在参数2的类型为Mat型的时候有效，如果参数2为vector类型，则根据vector中元素类型来选择输出凸包到底是点的坐标还是原始输入点的索引，也就是说此时的参数4没有作用。 

　　void convexityDefects(InputArray contour, InputArray convexhull, OutputArray convexityDefects)

　　该函数的作用是对输入的轮廓contour，凸包集合来检测其轮廓的凸型缺陷，一个凸型缺陷结构体包括4个元素，缺陷起点坐标，缺陷终点坐标，缺陷中离凸包线距离最远的点的坐标，以及此时最远的距离。参数3即其输出的凸型缺陷结构体向量。

　　其凸型缺陷的示意图如下所示：

　　

 

　　void findContours(InputOutputArray image, OutputArrayOfArrays contours, OutputArray hierarchy, int mode, int method, Point offset=Point()

　　该函数是找到输入图像image的轮廓,存储在contours中。输入的图像类型必须要求是8位单通道的二值图像，只要是非0元素都被看成是1，只要是0元素就被看做是0；参数hierarchy存储的是每个轮廓的拓扑信息，参数method表示轮廓提取的模式；参数4表示轮廓提取的近似方法，即怎么保存轮廓信息；参数5表示轮廓可移动的位移。 

　　void *memcpy(void *dest, const void *src, size_t n);

　　该函数的作用是从源src所指的内存地址的起始位置开始拷贝n个字节到目标dest所指的内存地址的起始位置中，主要不要把源地址和目的地址的顺序搞反了。

 

　　实验结果

　　在进行手部的提取时,因为要先提取出人体全身的骨骼,再定位手的坐标,所以人必须先处于站立状态,一旦人体骨骼提取成功后,可以改为坐立姿态,其手部提取并显示的一张图如下所示:

　　

 

　　网友Robert Walter把它的演示视频放在这里: http://www.youtube.com/watch?v=lCuItHQEgEQ&feature=player_embedded

 

 

　　实验主要部分代码和注释（参考资料中有工程代码下载地址）：

main.cpp:

#include "SkeletonSensor.h"

// openCV
#include <opencv/highgui.h>
#include <opencv/cv.h>
using namespace cv;

#include <iostream>
using namespace std;

// globals
SkeletonSensor* sensor;

const unsigned int XRES = 640;
const unsigned int YRES = 480;

const float DEPTH_SCALE_FACTOR = 255./4096.;

// defines the value about which thresholding occurs
const unsigned int BIN_THRESH_OFFSET = 5;

// defines the value about witch the region of interest is extracted
const unsigned int ROI_OFFSET = 70;

// median blur factor
const unsigned int MEDIAN_BLUR_K = 5;

// grasping threshold
const double GRASPING_THRESH = 0.9;

// colors
const Scalar COLOR_BLUE        = Scalar(240,40,0);
const Scalar COLOR_DARK_GREEN  = Scalar(0, 128, 0);
const Scalar COLOR_LIGHT_GREEN = Scalar(0,255,0);
const Scalar COLOR_YELLOW      = Scalar(0,128,200);
const Scalar COLOR_RED         = Scalar(0,0,255);

// returns true if the hand is near the sensor area
bool handApproachingDisplayPerimeter(float x, float y)
{
    return (x > (XRES - ROI_OFFSET)) || (x < (ROI_OFFSET)) ||
           (y > (YRES - ROI_OFFSET)) || (y < (ROI_OFFSET));
}

// conversion from cvConvexityDefect
struct ConvexityDefect
{
    Point start;
    Point end;
    Point depth_point;
    float depth;
};

// Thanks to Jose Manuel Cabrera for part of this C++ wrapper function
//Convexity為凸的意思，Defect為缺陷的意思，hull為殼的意思
//貌似這個函數在opencv中已經被實現了
void findConvexityDefects(vector<Point>& contour, vector<int>& hull, vector<ConvexityDefect>& convexDefects)
{
    if(hull.size() > 0 && contour.size() > 0)
    {
        CvSeq* contourPoints;
        CvSeq* defects;
        CvMemStorage* storage;
        CvMemStorage* strDefects;
        CvMemStorage* contourStr;
        CvConvexityDefect *defectArray = 0;

        strDefects = cvCreateMemStorage();
        defects = cvCreateSeq( CV_SEQ_KIND_GENERIC|CV_32SC2, sizeof(CvSeq),sizeof(CvPoint), strDefects );

        //We transform our vector<Point> into a CvSeq* object of CvPoint.
        contourStr = cvCreateMemStorage();
        contourPoints = cvCreateSeq(CV_SEQ_KIND_GENERIC|CV_32SC2, sizeof(CvSeq), sizeof(CvPoint), contourStr);
        for(int i = 0; i < (int)contour.size(); i++) {
            CvPoint cp = {contour[i].x,  contour[i].y};
            cvSeqPush(contourPoints, &cp);
        }

        //Now, we do the same thing with the hull index
        int count = (int) hull.size();
        //int hullK[count];
        int* hullK = (int*) malloc(count*sizeof(int));
        for(int i = 0; i < count; i++) { hullK[i] = hull.at(i); }
        CvMat hullMat = cvMat(1, count, CV_32SC1, hullK);

        // calculate convexity defects
        storage = cvCreateMemStorage(0);
        defects = cvConvexityDefects(contourPoints, &hullMat, storage);
        defectArray = (CvConvexityDefect*)malloc(sizeof(CvConvexityDefect)*defects->total);
        cvCvtSeqToArray(defects, defectArray, CV_WHOLE_SEQ);
        //printf("DefectArray %i %i\n",defectArray->end->x, defectArray->end->y);

        //We store defects points in the convexDefects parameter.
        for(int i = 0; i<defects->total; i++){
            ConvexityDefect def;
            def.start       = Point(defectArray[i].start->x, defectArray[i].start->y);
            def.end         = Point(defectArray[i].end->x, defectArray[i].end->y);
            def.depth_point = Point(defectArray[i].depth_point->x, defectArray[i].depth_point->y);
            def.depth       = defectArray[i].depth;
            convexDefects.push_back(def);
        }

    // release memory
    cvReleaseMemStorage(&contourStr);
    cvReleaseMemStorage(&strDefects);
    cvReleaseMemStorage(&storage);

    }
}

int main(int argc, char** argv)
{

    // initialize the kinect
    sensor = new SkeletonSensor();
    sensor->initialize();
    sensor->setPointModeToProjective();

    Mat depthRaw(YRES, XRES, CV_16UC1);
    Mat depthShow(YRES, XRES, CV_8UC1);
    Mat handDebug;
    
    // this vector holds the displayed images of the hands
    vector<Mat> debugFrames;

    // rectangle used to extract hand regions from depth map
    Rect roi;
    roi.width  = ROI_OFFSET*2;
    roi.height = ROI_OFFSET*2;

    namedWindow("depthFrame", CV_WINDOW_AUTOSIZE);
    namedWindow("leftHandFrame", CV_WINDOW_AUTOSIZE);
    namedWindow("rightHandFrame", CV_WINDOW_AUTOSIZE);


    int key = 0;
    while(key != 27 && key != 'q')
    {

        sensor->waitForDeviceUpdateOnUser();

        // update 16 bit depth matrix
        //參數3後面乘以2是因為kinect獲得的深度數據是1個像素2字節的
        memcpy(depthRaw.data, sensor->getDepthData(), XRES*YRES*2);
        //轉換成8位深度圖
        depthRaw.convertTo(depthShow, CV_8U, DEPTH_SCALE_FACTOR);

        for(int handI = 0; handI < 2; handI++)
        {

            int handDepth;
            if(sensor->getNumTrackedUsers() > 0)
            {
                //Skeleton是包含15個人體骨骼節點的結構體
                Skeleton skel =  sensor->getSkeleton(sensor->getUID(0));
                //struct SkeletonPoint
                //{
                //   float x, y, z, confidence;
                //};
                SkeletonPoint hand;

                if( handI == 0)
                    hand = skel.leftHand;//hand中保存左手點的座標
                else
                    hand = skel.rightHand;//hand中保存有手點的座標
                if(hand.confidence == 1.0)//手部的置信度为1
                {
                    handDepth = hand.z * (DEPTH_SCALE_FACTOR);//轉換為8bit后的深度值
                    //handApproachingDisplayPerimeter返回為真是說明，手的位置已經越界
                    if(!handApproachingDisplayPerimeter(hand.x, hand.y))
                    {
                        roi.x = hand.x - ROI_OFFSET;    //截取出感興趣的區域roi，其區域大小由經驗值來設定
                        roi.y = hand.y - ROI_OFFSET;
                    }
                }
            }
            else
                handDepth = -1;

            // extract hand from image
            Mat handCpy(depthShow, roi);    //handCpy只是與depthShow共用數據內存而已
            Mat handMat = handCpy.clone();    //真正的擁有自己的內存區域

            // binary threshold
            if(handDepth != -1)
                //BIN_THRESH_OFFSET == 5;
                //手部的閾值化，檢測到手部后，根據手部前後的深度信息來提取手的輪廓，此時，handMat就是0和1的矩陣了
                handMat = (handMat > (handDepth - BIN_THRESH_OFFSET)) & (handMat < (handDepth + BIN_THRESH_OFFSET));

            // last pre-filtering step, apply median blur
            medianBlur(handMat, handMat, MEDIAN_BLUR_K);

            // create debug image of thresholded hand and cvt to RGB so hints show in color
            handDebug = handMat.clone();
            debugFrames.push_back(handDebug);
            //CV_GRAY2RGB表示3个通道的值是一样的
            cvtColor(debugFrames[handI], debugFrames[handI], CV_GRAY2RGB);

            std::vector< std::vector<Point> > contours;
            //提取全部轮廓信息到contours，轮廓信息采用水平，垂直对角线的末断点存储。
            findContours(handMat, contours, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);

            //下面就是画多边形和点
            if (contours.size()) {
                for (int i = 0; i < contours.size(); i++) {
                    vector<Point> contour = contours[i];
                    //将vector转换成Mat型，此时的Mat还是列向量，只不过是2个通道的列向量而已
                    Mat contourMat = Mat(contour);
                    //返回轮廓的面积
                    double cArea = contourArea(contourMat);

                    if(cArea > 2000) // likely the hand
                    {
                        //找到轮廓的中心点
                        Scalar center = mean(contourMat);
                        Point centerPoint = Point(center.val[0], center.val[1]);

                        // approximate the contour by a simple curve
                        vector<Point> approxCurve;
                        //求出轮廓的封闭的曲线，保存在approxCurve，轮廓和封闭曲线直接的最大距离为10
                        approxPolyDP(contourMat, approxCurve, 10, true);

                        vector< vector<Point> > debugContourV;
                        debugContourV.push_back(approxCurve);
                        //在参数1中画出轮廓参数2，参数2必须是轮廓的集合，所以参数2是
                        //vector< vector<Point> >类型
                        //深绿色代表近似多边形
                        drawContours(debugFrames[handI], debugContourV, 0, COLOR_DARK_GREEN, 3);

                        vector<int> hull;
                        //找出近似曲线的凸包集合，集合hull中存储的是轮廓中凸包点的下标
                        convexHull(Mat(approxCurve), hull, false, false);

                        // draw the hull points
                        for(int j = 0; j < hull.size(); j++)
                        {
                            int index = hull[j];
                            //凸顶点用黄色表示
                            circle(debugFrames[handI], approxCurve[index], 3, COLOR_YELLOW, 2);
                        }

                        // find convexity defects
                        vector<ConvexityDefect> convexDefects;
                        findConvexityDefects(approxCurve, hull, convexDefects);
                        printf("Number of defects: %d.\n", (int) convexDefects.size());

                        for(int j = 0; j < convexDefects.size(); j++)
                        {
                            //缺陷点用蓝色表示
                            circle(debugFrames[handI], convexDefects[j].depth_point, 3, COLOR_BLUE, 2);

                        }
                        
                        // assemble point set of convex hull
                        //将凸包集以点的坐标形式保存下来
                        vector<Point> hullPoints;
                        for(int k = 0; k < hull.size(); k++)
                        {
                            int curveIndex = hull[k];
                            Point p = approxCurve[curveIndex];
                            hullPoints.push_back(p);
                        }

                        // area of hull and curve
                        double hullArea  = contourArea(Mat(hullPoints));
                        double curveArea = contourArea(Mat(approxCurve));
                        double handRatio = curveArea/hullArea;

                        // hand is grasping
                        //GRASPING_THRESH == 0.9
                        if(handRatio > GRASPING_THRESH)
                            //握拳表示绿色
                            circle(debugFrames[handI], centerPoint, 5, COLOR_LIGHT_GREEN, 5);
                        else
                            //一般情况下手张开其中心点是显示红色
                            circle(debugFrames[handI], centerPoint, 5, COLOR_RED, 5);
                    }
                } // contour conditional
            } // hands loop
        }

        imshow("depthFrame", depthShow);
        
        //debugFrames只保存2帧图像
        if(debugFrames.size() >= 2 )
        {
            //长和宽的尺寸都扩大3倍
            resize(debugFrames[0], debugFrames[0], Size(), 3, 3);
            resize(debugFrames[1], debugFrames[1], Size(), 3, 3);
            imshow("leftHandFrame",  debugFrames[0]);
            imshow("rightHandFrame",  debugFrames[1]);
            debugFrames.clear();
        }


        key = waitKey(10);

    }

    delete sensor;

    return 0;
}

skeletonSensor.h:

#ifndef SKELETON_SENSOR_H
#define SKELETON_SENSOR_H

#include <XnCppWrapper.h>
#include <vector>

// A 3D point with the confidence of the point's location. confidence_ > 0.5 is good
struct SkeletonPoint
{
    float x, y, z, confidence;
};

struct Skeleton
{
    SkeletonPoint head;
    SkeletonPoint neck;
    SkeletonPoint rightShoulder;
    SkeletonPoint leftShoulder;
    SkeletonPoint rightElbow;
    SkeletonPoint leftElbow;
    SkeletonPoint rightHand;
    SkeletonPoint leftHand;
    SkeletonPoint rightHip;
    SkeletonPoint leftHip;
    SkeletonPoint rightKnee;
    SkeletonPoint leftKnee;
    SkeletonPoint rightFoot;
    SkeletonPoint leftFoot;
    SkeletonPoint torso;

};

// SkeletonSensor: A wrapper for OpenNI Skeleton tracking devices
//
// Requires the OpenNI + NITE framework installation and the device driver
// Tracks users within the device FOV, and assists in collection of user joints data
class SkeletonSensor
{
    public:
        SkeletonSensor();
        ~SkeletonSensor();

        // set up the device resolution and data generators
        int initialize();

        // non-blocking wait for new data on the device
        void waitForDeviceUpdateOnUser();

        // update vector of tracked users
        void updateTrackedUsers();

        // return true if UID is among the tracked users
        bool isTracking(const unsigned int uid);

        // returns skeleton of specified user
        Skeleton getSkeleton(const unsigned int uid);

        // returns vector of skeletons for all users
        std::vector<Skeleton> getSkeletons();

        // get number of tracked users
        unsigned int getNumTrackedUsers();

        // map tracked user index to UID
        unsigned int getUID(const unsigned int index);

        // change point mode
        void setPointModeToProjective();
        void setPointModeToReal();
        
        // get depth and image data
        const XnDepthPixel* getDepthData();
        const XnDepthPixel* getWritableDepthData(){};
        const XnUInt8* getImageData();
        const XnLabel*     getLabels();

    private:
        xn::Context context_;
        xn::DepthGenerator depthG_;
        xn::UserGenerator userG_;
        xn::ImageGenerator imageG_;

        std::vector<unsigned int> trackedUsers_;
        
        // current list of hands
        //std::list<XnPoint3D> handCursors;

        bool pointModeProjective_;

        // on user detection and calibration, call specified functions
        int setCalibrationPoseCallbacks();

        // joint to point conversion, considers point mode
        void convertXnJointsToPoints(XnSkeletonJointPosition* const j, SkeletonPoint* const p, unsigned int numPoints);

        // callback functions for user and skeleton calibration events
        static void XN_CALLBACK_TYPE newUserCallback(xn::UserGenerator& generator, XnUserID nId, void* pCookie);
        static void XN_CALLBACK_TYPE lostUserCallback(xn::UserGenerator& generator, XnUserID nId, void* pCookie);
        static void XN_CALLBACK_TYPE calibrationStartCallback(xn::SkeletonCapability& capability, XnUserID nId, void* pCookie);
        static void XN_CALLBACK_TYPE calibrationCompleteCallback(xn::SkeletonCapability& capability, XnUserID nId, XnCalibrationStatus eStatus, void* pCookie);
        static void XN_CALLBACK_TYPE poseDetectedCallback(xn::PoseDetectionCapability& capability, const XnChar* strPose, XnUserID nId, void* pCookie);
};

#endif

skeletonSensor.cpp:

#include "SkeletonSensor.h"
#include "log.h"

inline int CHECK_RC(const unsigned int rc, const char* const description)
{
    if(rc != XN_STATUS_OK)
    {
        put_flog(LOG_ERROR, "%s failed: %s", description, xnGetStatusString(rc));
        return -1;
    }

    return 0;
}

SkeletonSensor::SkeletonSensor()
{
    pointModeProjective_ = false;
}

SkeletonSensor::~SkeletonSensor()
{
    context_.Shutdown();
}

int SkeletonSensor::initialize()
{
    context_.Init();

    XnStatus rc = XN_STATUS_OK;

    // create depth and user generators
    rc = depthG_.Create(context_);

    if(CHECK_RC(rc, "Create depth generator") == -1)
        return -1;

    rc = userG_.Create(context_);

    if(CHECK_RC(rc, "Create user generator") == -1)
        return -1;
        
    rc = imageG_.Create(context_);
    
     if(CHECK_RC(rc, "Create image generator") == -1)
        return -1;

    XnMapOutputMode mapMode;
    depthG_.GetMapOutputMode(mapMode);

    // for now, make output map VGA resolution at 30 FPS
    mapMode.nXRes = XN_VGA_X_RES;
    mapMode.nYRes = XN_VGA_Y_RES;
    mapMode.nFPS  = 30;

    depthG_.SetMapOutputMode(mapMode);
    imageG_.SetMapOutputMode(mapMode);

    // turn on device mirroring
    if(depthG_.IsCapabilitySupported("Mirror") == true)
    {
        rc = depthG_.GetMirrorCap().SetMirror(true);
        CHECK_RC(rc, "Setting Image Mirroring on depthG");
    }
    
    // turn on device mirroring
    if(imageG_.IsCapabilitySupported("Mirror") == true)
    {
        rc = imageG_.GetMirrorCap().SetMirror(true);
        CHECK_RC(rc, "Setting Image Mirroring on imageG");
    }

    // make sure the user points are reported from the POV of the depth generator
    userG_.GetAlternativeViewPointCap().SetViewPoint(depthG_);
    depthG_.GetAlternativeViewPointCap().SetViewPoint(imageG_);

    // set smoothing factor
    userG_.GetSkeletonCap().SetSmoothing(0.9);

    // start data streams
    context_.StartGeneratingAll();

    // setup callbacks
    setCalibrationPoseCallbacks();

    return 0;
}

void SkeletonSensor::waitForDeviceUpdateOnUser()
{
    context_.WaitOneUpdateAll(userG_);
    updateTrackedUsers();
}

void SkeletonSensor::updateTrackedUsers()
{
    XnUserID users[64];
    XnUInt16 nUsers = userG_.GetNumberOfUsers();

    trackedUsers_.clear();

    userG_.GetUsers(users, nUsers);

    for(int i = 0; i < nUsers; i++)
    {
        if(userG_.GetSkeletonCap().IsTracking(users[i]))
        {
            trackedUsers_.push_back(users[i]);
        }
    }
}

bool SkeletonSensor::isTracking(const unsigned int uid)
{
    return userG_.GetSkeletonCap().IsTracking(uid);
}

Skeleton SkeletonSensor::getSkeleton(const unsigned int uid)
{
    Skeleton result;

    // not tracking user
    if(!userG_.GetSkeletonCap().IsTracking(uid))
        return result;

    // Array of available joints
    const unsigned int nJoints = 15;
    XnSkeletonJoint joints[nJoints] = 
    {   XN_SKEL_HEAD,
        XN_SKEL_NECK,
        XN_SKEL_RIGHT_SHOULDER,
        XN_SKEL_LEFT_SHOULDER,
        XN_SKEL_RIGHT_ELBOW,
        XN_SKEL_LEFT_ELBOW,
        XN_SKEL_RIGHT_HAND,
        XN_SKEL_LEFT_HAND,
        XN_SKEL_RIGHT_HIP,
        XN_SKEL_LEFT_HIP,
        XN_SKEL_RIGHT_KNEE,
        XN_SKEL_LEFT_KNEE,
        XN_SKEL_RIGHT_FOOT,
        XN_SKEL_LEFT_FOOT,
        XN_SKEL_TORSO 
    };

    // holds the joint position components
    XnSkeletonJointPosition positions[nJoints];

    for (unsigned int i = 0; i < nJoints; i++)
    {
        userG_.GetSkeletonCap().GetSkeletonJointPosition(uid, joints[i], *(positions+i));
    }

    SkeletonPoint points[15];
    convertXnJointsToPoints(positions, points, nJoints);

    result.head              = points[0];
    result.neck              = points[1];
    result.rightShoulder     = points[2];
    result.leftShoulder      = points[3];
    result.rightElbow        = points[4];
    result.leftElbow         = points[5];
    result.rightHand         = points[6];
    result.leftHand          = points[7];
    result.rightHip          = points[8];
    result.leftHip           = points[9];
    result.rightKnee         = points[10];
    result.leftKnee          = points[11];
    result.rightFoot         = points[12];
    result.leftFoot          = points[13];
    result.torso             = points[14];

    return result;
}

std::vector<Skeleton> SkeletonSensor::getSkeletons()
{
    std::vector<Skeleton> skeletons;

    for(unsigned int i = 0; i < getNumTrackedUsers(); i++)
    {
        Skeleton s = getSkeleton(trackedUsers_[i]);
        skeletons.push_back(s);
    }

    return skeletons;
}

unsigned int SkeletonSensor::getNumTrackedUsers()
{
    return trackedUsers_.size();
}

unsigned int SkeletonSensor::getUID(const unsigned int index)
{
    return trackedUsers_[index];
}

void SkeletonSensor::setPointModeToProjective()
{
    pointModeProjective_ = true;
}

void SkeletonSensor::setPointModeToReal()
{
    pointModeProjective_ = false;
}

const XnDepthPixel* SkeletonSensor::getDepthData()
{
    return depthG_.GetDepthMap();
}

const XnUInt8* SkeletonSensor::getImageData()
{
    return imageG_.GetImageMap();
}

const XnLabel* SkeletonSensor::getLabels()
{
    xn::SceneMetaData sceneMD;
    
    userG_.GetUserPixels(0, sceneMD);
    
    return sceneMD.Data();
}

int SkeletonSensor::setCalibrationPoseCallbacks()
{
    XnCallbackHandle hUserCallbacks, hCalibrationStart, hCalibrationComplete;

    userG_.RegisterUserCallbacks(newUserCallback, lostUserCallback, this, hUserCallbacks);
    userG_.GetSkeletonCap().RegisterToCalibrationStart(calibrationStartCallback, this, hCalibrationStart);
    userG_.GetSkeletonCap().RegisterToCalibrationComplete(calibrationCompleteCallback, this, hCalibrationComplete);

    // turn on tracking of all joints
    userG_.GetSkeletonCap().SetSkeletonProfile(XN_SKEL_PROFILE_ALL);

    return 0;
}

void SkeletonSensor::convertXnJointsToPoints(XnSkeletonJointPosition* const joints, SkeletonPoint* const points, unsigned int numPoints)
{
    XnPoint3D xpt;

    for(unsigned int i = 0; i < numPoints; i++)
    {
        xpt = joints[i].position;

        if(pointModeProjective_)
            depthG_.ConvertRealWorldToProjective(1, &xpt, &xpt);

        points[i].confidence = joints[i].fConfidence;
        points[i].x = xpt.X;
        points[i].y = xpt.Y;
        points[i].z = xpt.Z;
    }
}

void XN_CALLBACK_TYPE SkeletonSensor::newUserCallback(xn::UserGenerator& generator, XnUserID nId, void* pCookie)
{
    put_flog(LOG_DEBUG, "New user %d, auto-calibrating", nId);

    SkeletonSensor* sensor = (SkeletonSensor*) pCookie;
    sensor->userG_.GetSkeletonCap().RequestCalibration(nId, true);
}

void XN_CALLBACK_TYPE SkeletonSensor::lostUserCallback(xn::UserGenerator& generator, XnUserID nId, void* pCookie)
{
    put_flog(LOG_DEBUG, "Lost user %d", nId);
}

void XN_CALLBACK_TYPE SkeletonSensor::calibrationStartCallback(xn::SkeletonCapability& capability, XnUserID nId, void* pCookie)
{
    put_flog(LOG_DEBUG, "Calibration started for user %d", nId);
}

void XN_CALLBACK_TYPE SkeletonSensor::calibrationCompleteCallback(xn::SkeletonCapability& capability, XnUserID nId, XnCalibrationStatus eStatus, void* pCookie)
{
    SkeletonSensor* sensor = (SkeletonSensor*) pCookie;

    if(eStatus == XN_CALIBRATION_STATUS_OK)
    {
        put_flog(LOG_DEBUG, "Calibration completed: start tracking user %d", nId);

        sensor->userG_.GetSkeletonCap().StartTracking(nId);
    }
    else
    {
        put_flog(LOG_DEBUG, "Calibration failed for user %d", nId);

        sensor->userG_.GetSkeletonCap().RequestCalibration(nId, true);
    }
}

void XN_CALLBACK_TYPE SkeletonSensor::poseDetectedCallback(xn::PoseDetectionCapability& capability, const XnChar* strPose, XnUserID nId, void* pCookie)
{
    put_flog(LOG_DEBUG, "Pose detected for user %d", nId);

    SkeletonSensor* sensor = (SkeletonSensor*) pCookie;

    sensor->userG_.GetPoseDetectionCap().StopPoseDetection(nId);
    sensor->userG_.GetSkeletonCap().RequestCalibration(nId, true);
}

 

 　 实验总结：通过本次实验，可以学会初步结合OpenCV和OpenNI来简单的提取手部所在的区域。

 

 

　　参考资料:

     heresy博文：http://kheresy.wordpress.com/2012/08/23/hand-processing-with-openni/

     Robert Walter工程代码下载：http://dl.dropbox.com/u/5505209/FingertipTuio3d.zip

 

 　 附录：

　　听网友说本文提供的工程代码下载地址失效了，故现在提供本人以前测试的工程：http://download.csdn.net/detail/wuweigreat/5101183