How to take kinect video image and depth image with openCV c++?

Question

I'm new about opencv(c++) and kinect. I try to take a video image with c++ from kinect. I search everywhere but I didn't find anything. Because people are made using openNI or OpenKinect. I don't want to use this lib. How can I do it??

Thanks!!!

Answer 1

You could use the kinect for windows SDK to grab the frames, and then convert them to an opencv format. See this code example which does that in visual studio (found in this thread on the microsoft forums), unfortunately I don't have a kinect right now to test the code:

#include "stdafx.h"

#define COLOR_WIDTH 640    
#define COLOR_HIGHT 480    
#define DEPTH_WIDTH 320    
#define DEPTH_HIGHT 240    
#define SKELETON_WIDTH 640    
#define SKELETON_HIGHT 480    
#define CHANNEL 3

BYTE buf[DEPTH_WIDTH * DEPTH_HIGHT * CHANNEL];

int drawColor(HANDLE h, IplImage* color)    
{
    const NUI_IMAGE_FRAME * pImageFrame = NULL;
    HRESULT hr = NuiImageStreamGetNextFrame(h, 0, &pImageFrame);
    if (FAILED(hr)) 
    {
        cout << "Get Image Frame Failed" << endl;
        return -1;
    }
    NuiImageBuffer * pTexture = pImageFrame->pFrameTexture;
    KINECT_LOCKED_RECT LockedRect;
    pTexture->LockRect(0, &LockedRect, NULL, 0);
    if (LockedRect.Pitch != 0)
    {
        BYTE * pBuffer = (BYTE*) LockedRect.pBits;
        cvSetData(color, pBuffer, LockedRect.Pitch);
    }
    cvShowImage("color image", color);
    NuiImageStreamReleaseFrame(h, pImageFrame);
    return 0;
}

int drawDepth(HANDLE h, IplImage* depth)
{
    const NUI_IMAGE_FRAME * pImageFrame = NULL;
    HRESULT hr = NuiImageStreamGetNextFrame(h, 0, &pImageFrame);
    if (FAILED(hr))
    {
        cout << "Get Image Frame Failed" << endl;
        return -1;
    }
    //  temp1 = depth;
    NuiImageBuffer * pTexture = pImageFrame->pFrameTexture;
    KINECT_LOCKED_RECT LockedRect;
    pTexture->LockRect(0, &LockedRect, NULL, 0);
    if (LockedRect.Pitch != 0)
    {
        USHORT * pBuff = (USHORT*) LockedRect.pBits;
        for (int i = 0; i < DEPTH_WIDTH * DEPTH_HIGHT; i++)
        {
            BYTE index = pBuff[i] & 0x07;
            USHORT realDepth = (pBuff[i] & 0xFFF8) >> 3;
            BYTE scale = 255 - (BYTE)(256 * realDepth / 0x0fff);
            buf[CHANNEL * i] = buf[CHANNEL * i + 1] = buf[CHANNEL * i + 2] = 0;
            switch (index)
            {
            case 0:
                buf[CHANNEL * i] = scale / 2;
                buf[CHANNEL * i + 1] = scale / 2;
                buf[CHANNEL * i + 2] = scale / 2;
                break;
            case 1:
                buf[CHANNEL * i] = scale;
                break;
            case 2:
                buf[CHANNEL * i + 1] = scale;
                break;
            case 3:
                buf[CHANNEL * i + 2] = scale;
                break;
            case 4:
                buf[CHANNEL * i] = scale;
                buf[CHANNEL * i + 1] = scale;
                break;
            case 5:
                buf[CHANNEL * i] = scale;
                buf[CHANNEL * i + 2] = scale;
                break;
            case 6:
                buf[CHANNEL * i + 1] = scale;
                buf[CHANNEL * i + 2] = scale;
                break;
            case 7:
                buf[CHANNEL * i] = 255 - scale / 2;
                buf[CHANNEL * i + 1] = 255 - scale / 2;
                buf[CHANNEL * i + 2] = 255 - scale / 2;
                break;
            }
        }
        cvSetData(depth, buf, DEPTH_WIDTH * CHANNEL);
    }
    NuiImageStreamReleaseFrame(h, pImageFrame);
    cvShowImage("depth image", depth);
    return 0;
}

int drawSkeleton(IplImage* skeleton)
{
    NUI_SKELETON_FRAME SkeletonFrame;
    CvPoint pt[20];
    HRESULT hr = NuiSkeletonGetNextFrame(0, &SkeletonFrame);
    bool bFoundSkeleton = false;
    for (int i = 0; i < NUI_SKELETON_COUNT; i++)
    {
        if (SkeletonFrame.SkeletonData[i].eTrackingState
                == NUI_SKELETON_TRACKED)
        {
            bFoundSkeleton = true;
        }
    }
    // Has skeletons!
    //
    if (bFoundSkeleton)
    {
        NuiTransformSmooth(&SkeletonFrame, NULL);
        memset(skeleton->imageData, 0, skeleton->imageSize);
        for (int i = 0; i < NUI_SKELETON_COUNT; i++)
        {
            if (SkeletonFrame.SkeletonData[i].eTrackingState
                    == NUI_SKELETON_TRACKED)
            {
                for (int j = 0; j < NUI_SKELETON_POSITION_COUNT; j++)
                {
                    float fx, fy;
                    NuiTransformSkeletonToDepthImageF(
                            SkeletonFrame.SkeletonData[i].SkeletonPositions[j],
                            &fx, &fy);
                    pt[j].x = (int) (fx * SKELETON_WIDTH + 0.5f);
                    pt[j].y = (int) (fy * SKELETON_HIGHT + 0.5f);
                    cvCircle(skeleton, pt[j], 5, CV_RGB(255, 0, 0), -1);
                }

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HEAD],
                        pt[NUI_SKELETON_POSITION_SHOULDER_CENTER],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_SHOULDER_CENTER],
                        pt[NUI_SKELETON_POSITION_SPINE], CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_SPINE],
                        pt[NUI_SKELETON_POSITION_HIP_CENTER],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HAND_RIGHT],
                        pt[NUI_SKELETON_POSITION_WRIST_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_WRIST_RIGHT],
                        pt[NUI_SKELETON_POSITION_ELBOW_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_ELBOW_RIGHT],
                        pt[NUI_SKELETON_POSITION_SHOULDER_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_SHOULDER_RIGHT],
                        pt[NUI_SKELETON_POSITION_SHOULDER_CENTER],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_SHOULDER_CENTER],
                        pt[NUI_SKELETON_POSITION_SHOULDER_LEFT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_SHOULDER_LEFT],
                        pt[NUI_SKELETON_POSITION_ELBOW_LEFT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_ELBOW_LEFT],
                        pt[NUI_SKELETON_POSITION_WRIST_LEFT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_WRIST_LEFT],
                        pt[NUI_SKELETON_POSITION_HAND_LEFT], CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HIP_CENTER],
                        pt[NUI_SKELETON_POSITION_HIP_RIGHT], CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HIP_RIGHT],
                        pt[NUI_SKELETON_POSITION_KNEE_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_KNEE_RIGHT],
                        pt[NUI_SKELETON_POSITION_ANKLE_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_ANKLE_RIGHT],
                        pt[NUI_SKELETON_POSITION_FOOT_RIGHT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HIP_CENTER],
                        pt[NUI_SKELETON_POSITION_HIP_LEFT], CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_HIP_LEFT],
                        pt[NUI_SKELETON_POSITION_KNEE_LEFT], CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_KNEE_LEFT],
                        pt[NUI_SKELETON_POSITION_ANKLE_LEFT],
                        CV_RGB(0, 255, 0));

                cvLine(skeleton, pt[NUI_SKELETON_POSITION_ANKLE_LEFT],
                        pt[NUI_SKELETON_POSITION_FOOT_LEFT], CV_RGB(0, 255, 0));
            }
        }
    }
    cvShowImage("skeleton image", skeleton);
    return 0;
}

int main(int argc, char * argv[])
{
    IplImage* color = cvCreateImageHeader(cvSize(COLOR_WIDTH, COLOR_HIGHT), IPL_DEPTH_8U, 4);

    IplImage* depth = cvCreateImageHeader(cvSize(DEPTH_WIDTH, DEPTH_HIGHT),IPL_DEPTH_8U, CHANNEL);

    IplImage* skeleton = cvCreateImage(cvSize(SKELETON_WIDTH, SKELETON_HIGHT),IPL_DEPTH_8U, CHANNEL);

    cvNamedWindow("color image", CV_WINDOW_AUTOSIZE);

    cvNamedWindow("depth image", CV_WINDOW_AUTOSIZE);

    cvNamedWindow("skeleton image", CV_WINDOW_AUTOSIZE);

    HRESULT hr = NuiInitialize(
            NUI_INITIALIZE_FLAG_USES_DEPTH_AND_PLAYER_INDEX
            | NUI_INITIALIZE_FLAG_USES_COLOR
            | NUI_INITIALIZE_FLAG_USES_SKELETON);

    if (hr != S_OK)
    {
        cout << "NuiInitialize failed" << endl;
        return hr;
    }

    HANDLE h1 = CreateEvent(NULL, TRUE, FALSE, NULL);
    HANDLE h2 = NULL;
    hr = NuiImageStreamOpen(NUI_IMAGE_TYPE_COLOR, NUI_IMAGE_RESOLUTION_640x480,
            0, 2, h1, &h2);
    if (FAILED(hr))
    {
        cout << "Could not open image stream video" << endl;
        return hr;
    }

    HANDLE h3 = CreateEvent(NULL, TRUE, FALSE, NULL);
    HANDLE h4 = NULL;
    hr = NuiImageStreamOpen(NUI_IMAGE_TYPE_DEPTH_AND_PLAYER_INDEX,
            NUI_IMAGE_RESOLUTION_320x240, 0, 2, h3, &h4);
    if (FAILED(hr))
    {
        cout << "Could not open depth stream video" << endl;
        return hr;
    }

    HANDLE h5 = CreateEvent(NULL, TRUE, FALSE, NULL);
    hr = NuiSkeletonTrackingEnable(h5, 0);
    if (FAILED(hr))
    {
        cout << "Could not open skeleton stream video" << endl;
        return hr;
    }

    while (1)
    {
        WaitForSingleObject(h1, INFINITE);
        drawColor(h2, color);
        WaitForSingleObject(h3, INFINITE);
        drawDepth(h4, depth);
        WaitForSingleObject(h5, INFINITE);
        drawSkeleton(skeleton);

        //exit
        int c = cvWaitKey(1);
        if (c == 27 || c == 'q' || c == 'Q')
            break;
    }

    cvReleaseImageHeader(&depth);
    cvReleaseImageHeader(&color);
    cvReleaseImage(&skeleton);
    cvDestroyWindow("depth image");
    cvDestroyWindow("color image");
    cvDestroyWindow("skeleton image");

    NuiShutdown();

    return 0;

}

Answer 2

OpenCV does not offer the ability to connect to and process data from the Kinect sensor; unless you treat the Kinect as a regular webcam. You will want to fetch the data using one of the APIs and send it to OpenCV. To get the data from the Kinect you can use:

• Microsoft Kinect for Windows SDK
• OpenKinect's libfreenect API
• OpenNI + OpenKinect

If your employer has a problem with one of the APIs, that is there choice. But the use of OpenCV does not eliminate your need to use one of them.

A quick search on MSDN reveals multiple threads on the the subject. The most straight forward approach I've read about is using cvSetData to import the data, after converting the image:

RGB

IplImage * ovImage = NULL;
ovImage = cvCreateImage(cvSize(640, 480), 8, 4);
cvSetData(ovImage, pBuffer, ovImage->widthStep);

Depth

ovImage = cvCreateImage(cvSize(640, 480), 8, 1);

I also found the freenomad_vision project on GitHub that provides libfreenect support with OpenCV and OpenGL. If you dislike using libfreenect, the code can easily serve as reference since the incoming data is all the same and (likely) would be converted the same.