ios5 的face detection方法

來源：
http://maniacdev.com/2011/11/tutorial-easy-face-detection-with-core-image-in-ios-5/


要看CIFaceFeature Class Reference
目前只能偵測臉
細部的話可以偵測到左右眼還有嘴吧的位置

跟openCV比起來，ios5內建的方法沒有算到額頭的位置 ....囧
要動態改變height,來猜整個臉的高度
但我想這只是時間的問題，之後一定會改進的

詳細code如下
有用到CoreImage 和QuartzCore

-(void)markFaces:(UIImageView *)facePicture

{

    // draw a CI image with the previously loaded face detection picture

    CIImage* image = [CIImage imageWithCGImage:facePicture.image.CGImage];

    

    // create a face detector - since speed is not an issue we'll use a high accuracy

    // detector

    CIDetector* detector = [CIDetector detectorOfType:CIDetectorTypeFace 

                                              context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy]];

    

    // create an array containing all the detected faces from the detector    

    NSArray* features = [detector featuresInImage:image];

    

    // we'll iterate through every detected face.  CIFaceFeature provides us

    // with the width for the entire face, and the coordinates of each eye

    // and the mouth if detected.  Also provided are BOOL's for the eye's and

    // mouth so we can check if they already exist.

    for(CIFaceFeature* faceFeature in features)

    {

        // get the width of the face

        CGFloat faceWidth = faceFeature.bounds.size.width;

        CGFloat faceHeight = faceFeature.bounds.size.height;

        

        // create a UIView using the bounds of the face

        UIView* faceView = [[UIView alloc] initWithFrame:faceFeature.bounds];

        

        // add a border around the newly created UIView

        

        faceView.layer.borderWidth = 1;

        faceView.layer.borderColor = [[UIColor redColor] CGColor];

        

        // add the new view to create a box around the face

        [self.window addSubview:faceView];

        

        if(faceFeature.hasLeftEyePosition)

        {

            // create a UIView with a size based on the width of the face

            UIView* leftEyeView = [[UIView alloc] initWithFrame:CGRectMake(faceFeature.leftEyePosition.x-faceWidth*0.15, faceFeature.leftEyePosition.y-faceWidth*0.15, faceWidth*0.3, faceWidth*0.3)];

            // change the background color of the eye view

            [leftEyeView setBackgroundColor:[[UIColor blueColor] colorWithAlphaComponent:0.3]];

            // set the position of the leftEyeView based on the face

            [leftEyeView setCenter:faceFeature.leftEyePosition];

            // round the corners

            leftEyeView.layer.cornerRadius = faceWidth*0.15;

            // add the view to the window

            [self.window addSubview:leftEyeView];

        }

        

        if(faceFeature.hasRightEyePosition)

        {

            // create a UIView with a size based on the width of the face

            UIView* leftEye = [[UIView alloc] initWithFrame:CGRectMake(faceFeature.rightEyePosition.x-faceWidth*0.15, faceFeature.rightEyePosition.y-faceWidth*0.15, faceWidth*0.3, faceWidth*0.3)];

            // change the background color of the eye view

            [leftEye setBackgroundColor:[[UIColor blueColor] colorWithAlphaComponent:0.3]];

            // set the position of the rightEyeView based on the face

            [leftEye setCenter:faceFeature.rightEyePosition];

            // round the corners

            leftEye.layer.cornerRadius = faceWidth*0.15;

            // add the new view to the window

            [self.window addSubview:leftEye];

        }

        

        if(faceFeature.hasMouthPosition)

        {

            // create a UIView with a size based on the width of the face

            UIView* mouth = [[UIView alloc] initWithFrame:CGRectMake(faceFeature.mouthPosition.x-faceWidth*0.2, faceFeature.mouthPosition.y-faceWidth*0.2, faceWidth*0.4, faceWidth*0.4)];

            // change the background color for the mouth to green

            [mouth setBackgroundColor:[[UIColor greenColor] colorWithAlphaComponent:0.3]];

            // set the position of the mouthView based on the face

            [mouth setCenter:faceFeature.mouthPosition];

            // round the corners

            mouth.layer.cornerRadius = faceWidth*0.2;

            // add the new view to the window

            [self.window addSubview:mouth];

        }

        

    }

}