Face detection In swift

By using Vision framework you can do many things like detection of faces, face features, object tracking, and others.

In this blog, we will take a look at how we can detect a face from an image. Following are the steps to perform face detection

• First, you need an image from which you can detect a face from an image this is taken from the camera or a Photos from your iPhone, you can use for this UIImagePickerController
  
  let picker = UIImagePickerController() picker.delegate = self let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet) if UIImagePickerController.isSourceTypeAvailable(.camera) { alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: {action in picker.sourceType = .camera self.present(picker, animated: true, completion: nil) })) } alert.addAction(UIAlertAction(title: "Photo Library", style: .default, handler: { action in picker.sourceType = .photoLibrary self.present(picker, animated: true, completion: nil) })) alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil)) alert.popoverPresentationController?.sourceRect = self.view.frame self.present(alert, animated: true, completion: nil)

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  let picker = UIImagePickerController() picker.delegate = self let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet) if UIImagePickerController.isSourceTypeAvailable(.camera) {     alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: {action in         picker.sourceType = .camera         self.present(picker, animated: true, completion: nil)     })) } alert.addAction(UIAlertAction(title: "Photo Library", style: .default, handler: { action in     picker.sourceType = .photoLibrary     self.present(picker, animated: true, completion: nil) })) alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil)) alert.popoverPresentationController?.sourceRect = self.view.frame self.present(alert, animated: true, completion: nil)

  
  Then use these delegate methods to get an image:
  
  extention ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate { func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) { dismiss(animated: true, completion: nil) self.image = info[UIImagePickerControllerOriginalImage] as! UIImage } }

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  extention ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {     func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {         dismiss(animated: true, completion: nil)         self.image = info[UIImagePickerControllerOriginalImage] as! UIImage       } }

• After fetching the image then you have to use that for detecting a face CIDetector find an example below for detecting a face.
  
  let imageOptions = NSDictionary(object: NSNumber(value: 5) as NSNumber, forKey: CIDetectorImageOrientation as NSString) let personciImage = CIImage(cgImage: image.cgImage!) let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh] let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy) let faces = faceDetector?.features(in: personciImage, options: imageOptions as? [String : AnyObject]) if let face = faces?.first as? CIFaceFeature { print("found bounds are \(face.bounds)") let alert = UIAlertController(title: "Say Cheese!", message: "We detected a face!", preferredStyle: UIAlertController.Style.alert) // alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil)) let confirmAction = UIAlertAction(title: "OK", style: .default) { [weak alert] _ in } alert.addAction(confirmAction) let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil) alert.addAction(cancelAction) } else { let alert = UIAlertController(title: "No Face!", message: "No face was detected", preferredStyle: UIAlertController.Style.alert) alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil)) self.present(alert, animated: true, completion: nil) }

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  let imageOptions =  NSDictionary(object: NSNumber(value: 5) as NSNumber, forKey: CIDetectorImageOrientation as NSString) let personciImage = CIImage(cgImage: image.cgImage!) let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh] let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy) let faces = faceDetector?.features(in: personciImage, options: imageOptions as? [String : AnyObject])   if let face = faces?.first as? CIFaceFeature {     print("found bounds are \(face.bounds)")     let alert = UIAlertController(title: "Say Cheese!", message: "We detected a face!", preferredStyle: UIAlertController.Style.alert) //            alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))     let confirmAction = UIAlertAction(title: "OK", style: .default) { [weak alert] _ in       }     alert.addAction(confirmAction)     let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)     alert.addAction(cancelAction) } else {      let alert = UIAlertController(title: "No Face!", message: "No face was detected", preferredStyle: UIAlertController.Style.alert)         alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))         self.present(alert, animated: true, completion: nil) }

• By using the help CIFaceFeature you can also detect that smiling face or face’s eye positioning and many others.
  
  if face.hasSmile { print("face is smiling"); } if face.hasLeftEyePosition { print("Left eye bounds are \(face.leftEyePosition)") } if face.hasRightEyePosition { print("Right eye bounds are \(face.rightEyePosition)") }

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  if face.hasSmile {         print("face is smiling");     }          if face.hasLeftEyePosition {         print("Left eye bounds are \(face.leftEyePosition)")     }          if face.hasRightEyePosition {         print("Right eye bounds are \(face.rightEyePosition)")     }

I hope you enjoyed this, please let me know in the comments how did it go and if there are things that can be improved. Thanks for tuning in once again!