Turning Scanner On/Off

My application uses the CloudReco's scanner by calling the CRParentViewController method in a storyboard from a menu.  The scanning works great.  I add a modal view afterwards.  However, when I try returning to the main menu and then calling the CRParentViewController again, I can not start up the scanner.  I know I need to add the targetFinder->startInit method to kick off scanning again and deinitialize the scanner when I move to my modal view.  As a result, I have added a deinitializeTracker method as follows:

- (void)deinitializeTracker {

    // Background thread must have its own autorelease pool

    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];

    QCAR::TrackerManager& trackerManager = QCAR::TrackerManager::getInstance();

    QCAR::ImageTracker* imageTracker = static_cast<QCAR::ImageTracker*>(trackerManager.getTracker(QCAR::Tracker::IMAGE_TRACKER));

    if (imageTracker == NULL)

    {

        NSLog(@"Failed to load tracking data set because the ImageTracker has not been initialized.");

    }

    QCAR::TargetFinder *targetFinder = imageTracker->getTargetFinder();

    if (targetFinder == NULL) {

        NSLog(@"Fialed to get target finder.");

    }

    // Deinitialize Visual Search

    targetFinder->deinit();

    [pool release];

}

I later call the loadTracker method in my ARViewController's ViewDidLoad method.  Unfortunately, I get the following error:

"Failed to load tracking data set because the ImageTracker has not been initialized"

Suggestions are welcome.