How to crop the detected face - ios

Question

I use CoreImage to detect the face. I want to crop the face after face detection. I use this snippet to detect face:
-(void)markFaces:(UIImageView *)facePicture{
CIImage* image = [CIImage imageWithCGImage:imageView.image.CGImage];
CIDetector* detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy]];
NSArray* features = [detector featuresInImage:image];
CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
transform = CGAffineTransformTranslate(transform, 0, -imageView.bounds.size.height);
for(CIFaceFeature* faceFeature in features)
{
// Get the face rect: Translate CoreImage coordinates to UIKit coordinates
const CGRect faceRect = CGRectApplyAffineTransform(faceFeature.bounds, transform);
faceView = [[UIView alloc] initWithFrame:faceRect];
faceView.layer.borderWidth = 1;
faceView.layer.borderColor = [[UIColor redColor] CGColor];
UIGraphicsBeginImageContext(faceView.bounds.size);
[faceView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//Blur the UIImage with a CIFilter
CIImage *imageToBlur = [CIImage imageWithCGImage:viewImage.CGImage];
CIFilter *gaussianBlurFilter = [CIFilter filterWithName: #"CIGaussianBlur"];
[gaussianBlurFilter setValue:imageToBlur forKey: #"inputImage"];
[gaussianBlurFilter setValue:[NSNumber numberWithFloat: 10] forKey: #"inputRadius"];
CIImage *resultImage = [gaussianBlurFilter valueForKey: #"outputImage"];
UIImage *endImage = [[UIImage alloc] initWithCIImage:resultImage];
//Place the UIImage in a UIImageView
UIImageView *newView = [[UIImageView alloc] initWithFrame:self.view.bounds];
newView.image = endImage;
[self.view addSubview:newView];
CGFloat faceWidth = faceFeature.bounds.size.width;
[imageView addSubview:faceView];
// LEFT EYE
if(faceFeature.hasLeftEyePosition)
{
const CGPoint leftEyePos = CGPointApplyAffineTransform(faceFeature.leftEyePosition, transform);
UIView *leftEyeView = [[UIView alloc] initWithFrame:CGRectMake(leftEyePos.x - faceWidth*EYE_SIZE_RATE*0.5f,
leftEyePos.y - faceWidth*EYE_SIZE_RATE*0.5f
,faceWidth*EYE_SIZE_RATE,
faceWidth*EYE_SIZE_RATE)];
NSLog(#"Left Eye X = %0.1f Y = %0.1f Width = %0.1f Height = %0.1f",leftEyePos.x - faceWidth*EYE_SIZE_RATE*0.5f,
leftEyePos.y - faceWidth*EYE_SIZE_RATE*0.5f,faceWidth*EYE_SIZE_RATE,
faceWidth*EYE_SIZE_RATE);
leftEyeView.backgroundColor = [[UIColor magentaColor] colorWithAlphaComponent:0.3];
leftEyeView.layer.cornerRadius = faceWidth*EYE_SIZE_RATE*0.5;
[imageView addSubview:leftEyeView];
}
// RIGHT EYE
if(faceFeature.hasRightEyePosition)
{
const CGPoint rightEyePos = CGPointApplyAffineTransform(faceFeature.rightEyePosition, transform);
UIView *rightEye = [[UIView alloc] initWithFrame:CGRectMake(rightEyePos.x - faceWidth*EYE_SIZE_RATE*0.5,
rightEyePos.y - faceWidth*EYE_SIZE_RATE*0.5,
faceWidth*EYE_SIZE_RATE,
faceWidth*EYE_SIZE_RATE)];
NSLog(#"Right Eye X = %0.1f Y = %0.1f Width = %0.1f Height = %0.1f",rightEyePos.x - faceWidth*EYE_SIZE_RATE*0.5f,
rightEyePos.y - faceWidth*EYE_SIZE_RATE*0.5f,faceWidth*EYE_SIZE_RATE,
faceWidth*EYE_SIZE_RATE);
rightEye.backgroundColor = [[UIColor blueColor] colorWithAlphaComponent:0.2];
rightEye.layer.cornerRadius = faceWidth*EYE_SIZE_RATE*0.5;
[imageView addSubview:rightEye];
}
// MOUTH
if(faceFeature.hasMouthPosition)
{
const CGPoint mouthPos = CGPointApplyAffineTransform(faceFeature.mouthPosition, transform);
UIView* mouth = [[UIView alloc] initWithFrame:CGRectMake(mouthPos.x - faceWidth*MOUTH_SIZE_RATE*0.5,
mouthPos.y - faceWidth*MOUTH_SIZE_RATE*0.5,
faceWidth*MOUTH_SIZE_RATE,
faceWidth*MOUTH_SIZE_RATE)];
NSLog(#"Mouth X = %0.1f Y = %0.1f Width = %0.1f Height = %0.1f",mouthPos.x - faceWidth*MOUTH_SIZE_RATE*0.5f,
mouthPos.y - faceWidth*MOUTH_SIZE_RATE*0.5f,faceWidth*MOUTH_SIZE_RATE,
faceWidth*MOUTH_SIZE_RATE);
mouth.backgroundColor = [[UIColor greenColor] colorWithAlphaComponent:0.3];
mouth.layer.cornerRadius = faceWidth*MOUTH_SIZE_RATE*0.5;
[imageView addSubview:mouth];
}
}
}
What I want is just crop the face.

Answer 1

You can easily crop the face using this function.it is tested and working properly.
-(void)faceWithFrame:(CGRect)frame{
CGRect rect = frame;
CGImageRef imageRef = CGImageCreateWithImageInRect([self.imageView.image CGImage], rect);
UIImage *cropedImage = [UIImage imageWithCGImage:imageRef];
self.cropedImg.image =cropedImage;
}
You just pass the face frame and the above function will give the crop face image.