get depth map from depth data kinect openni open cv - c++

Question

I m beginning in programming with openni and open cv I m working with the kinect .
here a part of the code that I m using to get de data depth map ( it s working )
Now my question is :
How could I get the depht map as an image in return ?
my data is on DepthPixel* pDepth1 and I want to display the image of the depth map (because I want to save her ).
Thank you
VideoFrameRef frame;
DepthPixel* pDepth1 = NULL;
DepthPixel* pDepth2 = NULL;
for (int i = 0; i < 2; i++)
{
int changedStreamDummy;
VideoStream* pStream = &depth;
rc = OpenNI::waitForAnyStream(&pStream, 1, &changedStreamDummy, SAMPLE_READ_WAIT_TIMEOUT);
if (rc != STATUS_OK)
{
printf("Wait failed! (timeout is %d ms)\n%s\n", SAMPLE_READ_WAIT_TIMEOUT, OpenNI::getExtendedError());
continue;
}
rc = depth.readFrame(&frame);
if (rc != STATUS_OK)
{
printf("Read failed!\n%s\n", OpenNI::getExtendedError());
continue;
}
if (frame.getVideoMode().getPixelFormat() != PIXEL_FORMAT_DEPTH_1_MM && frame.getVideoMode().getPixelFormat() != PIXEL_FORMAT_DEPTH_100_UM)
{
printf("Unexpected frame format\n");
continue;
}
if (i == 0){
int dummy;
cout << "Press any key to take first pic: ";
cin >> dummy;
pDepth1 = (DepthPixel*)frame.getData();
}
else{
int dummy;
cout << "Press any key to take second pic: ";
cin >> dummy;
pDepth2 = (DepthPixel*)frame.getData();
}

Answer 1

Assuming that you have your dependencies sorted out, the following has worked for me in the past
//set up the capture with the correct settings
VideoCapture capture = new VideoCapture;
capture->open(CV_CAP_OPENNI);
capture->set(CV_CAP_OPENNI_IMAGE_GENERATOR_OUTPUT_MODE, CV_CAP_OPENNI_VGA_30HZ);
//get an image and display it
Mat image;
capture->grab();
capture->retrieve(image, CV_CAP_OPENNI_DEPTH_MAP);
then work with the image as you would any other matrix. Remember that the image CV_16U as the capture records depths in 16 bit unsigned integers.