Image Tracker

The Image Tracker recognizes and tracks planar images. It can demonstrate not only 3D objects but also videos, even the transparent one.

Starting / Stopping the Tracker
Using the Tracking Information
Setting a Target Image
Adding / Replacing a Target Image
Changing Tracking Mode

Starting / Stopping the Tracker

To start / stop Tracker after loading the map, refer to the following code.

ImageTrackerViewController.mm

- (void)resumeAR
{
    ...
    TrackerManager::getInstance()->startTracker(TRACKER_TYPE_IMAGE);
}

- (void)pauseAR
{
    TrackerManager::getInstance()->stopTracker();
    ...
}

Using the Tracking Information

In the folder where SDK is installed, go to ‘data > SDKSample > Original > ImageTarget' folder, and there is sample target image. Print the image.

If you use the sample code, the following content will be augmented for each image.

  • Blocks.jpg: The alpha video is augmented.
  • Lego.jpg: The normal video is augmented.
  • Glacier.jpg: The cube with the texture is augmented.

To apply tracking results to augmented objects, refer to the following code.

ImageTrackerViewController.mm

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
    ...
    ITrackingResult *result = &TrackerManager::getInstance()->getTrackingResult();
    
    int trackingCount = (int)result->getCount();
    
    if(trackingCount > 0)
    {
        for (int i = 0; i < (int)result->getCount(); i++)
        {
            ITrackable *trackable = result->getTrackable(i);
            
            if(trackable->getName() == "Lego")
            {
                ...
            }
            else if(trackable->getName() == "Blocks")
            {
                ...
            }
            else if(trackable->getName() == "Glacier")
            {
                gl_helper::Mat4 pose = trackable->getPose();
                pose = projectionMatrix * pose;
                texturedCube>setTransform(pose);
                texturedCube>setPosition(0.0f, 0.0f, -0.05f);
                texturedCube>setScale(0.3f, 0.3f, 0.1f);
                texturedCube>draw();
            }
            ...
        }
    }
    ...
}

Setting a Target Image

By calling addTrackerData () to register the map file and calling loadTrackerData (), the target image can be tracked. To set a target image, refer to the following code.

ImageTrackerViewController.mm

- (void)startEngine
{
    ...
    NSString *blocksTrackerMapPath = [[NSBundle mainBundle] pathForResource:@"Blocks" ofType:@"2dmap" inDirectory:@"data/SDKSample"];
    NSString *glacierTrackerMapPath = [[NSBundle mainBundle] pathForResource:@"Glacier" ofType:@"2dmap" inDirectory:@"data/SDKSample"];
    NSString *legoTrackerMapPath = [[NSBundle mainBundle] pathForResource:@"Lego" ofType:@"2dmap" inDirectory:@"data/SDKSample"];
    
    TrackerManager::getInstance()->startTracker(TRACKER_TYPE_IMAGE);
    ...
    TrackerManager::getInstance()->addTrackerData(std::string([blocksTrackerMapPath UTF8String]));
    TrackerManager::getInstance()->addTrackerData(std::string([glacierTrackerMapPath UTF8String]));
    TrackerManager::getInstance()->addTrackerData(std::string([legoTrackerMapPath UTF8String]));
    
    TrackerManager::getInstance()->loadTrackerData();
}

Adding / Replacing a Target Image

  1. Create a map file refer to Documentation > Target Manager.

  2. Download the file you created.

  3. Unzip the downloaded file and copy it to the desired path.

  4. Set a target image.

Changing Tracking Mode

Image Tracker has three Tracking modes : normal, extended, and multi.

The default setting is normal mode.

  • normal mode: This is the normal image tracker.
TrackerManager::getInstance()->setTrackingOption(NORMAL_TRACKING);
  • extended mode: This function is traceable even when the distance from the target image is far away.
TrackerManager::getInstance()->setTrackingOption(EXTENDED_TRACKING);
  • multi mode: This function allows you to recognize and track up to three target images at the same time.
TrackerManager::getInstance()->setTrackingOption(MULTI_TRACKING);