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，http://qun.81nanchang.cn 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；http://tx.qqlove789.com 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。