问基于iOS加速度计的手势识别

EN

@implementation MainViewController {
    double previousLowPassFilteredAccelerationX;
double previousLowPassFilteredAccelerationY;
double previousLowPassFilteredAccelerationZ;

    CGPoint position;
    int numOfTrainedGestures;
    GeometricRecognizer recognizer;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

    previousLowPassFilteredAccelerationX = previousLowPassFilteredAccelerationY = previousLowPassFilteredAccelerationZ = 0.0;

    recognizer = GeometricRecognizer();

    //Note: I let the user train his own gestures, so i start up each time with 0 gestures
    numOfTrainedGestures = 0;
}

#define kLowPassFilteringFactor 0.1
#define MOVEMENT_HZ 50
#define NOISE_REDUCTION 0.05

- (IBAction)StartAccelerometer
{
    CMMotionManager *motionManager = [CMMotionManager SharedMotionManager];
    if ([motionManager isDeviceMotionAvailable])
    {
        [motionManager setDeviceMotionUpdateInterval:1.0/MOVEMENT_HZ];
        [motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue]
                                       withHandler: ^(CMDeviceMotion *motion, NSError *error)
         {
             CMAcceleration lowpassFilterAcceleration, userAcceleration = motion.userAcceleration;

             lowpassFilterAcceleration.x = (userAcceleration.x * kLowPassFilteringFactor) + (previousLowPassFilteredAccelerationX * (1.0 - kLowPassFilteringFactor));
             lowpassFilterAcceleration.y = (userAcceleration.y * kLowPassFilteringFactor) + (previousLowPassFilteredAccelerationY * (1.0 - kLowPassFilteringFactor));
             lowpassFilterAcceleration.z = (userAcceleration.z * kLowPassFilteringFactor) + (previousLowPassFilteredAccelerationZ * (1.0 - kLowPassFilteringFactor));

             if (lowpassFilterAcceleration.x > NOISE_REDUCTION || lowpassFilterAcceleration.y > NOISE_REDUCTION)
                 [self.points addObject:[NSString stringWithFormat:@"%.2f,%.2f", lowpassFilterAcceleration.x, lowpassFilterAcceleration.y]];

             previousLowPassFilteredAccelerationX = lowpassFilterAcceleration.x;
             previousLowPassFilteredAccelerationY = lowpassFilterAcceleration.y;
             previousLowPassFilteredAccelerationZ = lowpassFilterAcceleration.z;


             // Just viewing the points to the user
             self.XLabel.text = [NSString stringWithFormat:@"X : %.2f", lowpassFilterAcceleration.x];
             self.YLabel.text = [NSString stringWithFormat:@"Y : %.2f", lowpassFilterAcceleration.y];
             self.ZLabel.text = [NSString stringWithFormat:@"Z : %.2f", lowpassFilterAcceleration.z];
         }];
    }
    else NSLog(@"DeviceMotion is not available");
}


- (IBAction)StopAccelerometer
{
    [[CMMotionManager SharedMotionManager] stopDeviceMotionUpdates];

    // View all the points to the user
    self.pointsTextView.text = [NSString stringWithFormat:@"%d\n\n%@", self.points.count, [self.points componentsJoinedByString:@"\n"]];

    // There must be more that 2 trained gestures because in recognizing, it gets the closest one in distance
    if (numOfTrainedGestures > 1) {
        Path2D path = [self createPathFromPoints]; // A method to create a 2D path from pointsArray
        if (path.size()) {
            RecognitionResult recongnitionResult = recognizer.recognize(path);
            self.recognitionLabel.text = [NSString stringWithFormat:@"%s Detected with Prob %.2f !", recongnitionResult.name.c_str(),
                                      recongnitionResult.score];
        } else self.recognitionLabel.text = @"Not enough points for gesture !";
    }
    else self.recognitionLabel.text = @"Not enough templates !";

    [self releaseAllVariables];
}