How to add autofocus to AVCaptureSession? SWIFT

i0S Swift Issue

Question or problem in the Swift programming language:

I’m using AVFoundation to recognize text and perform OCR. How do I add autofocus? I don’t want to have the yellow square thing when user taps the screen, I just want it to automatically focus on the object, a credit card for example.

Here is my session code.

func setupSession() {
  session = AVCaptureSession()
  session.sessionPreset = AVCaptureSessionPresetHigh

  let camera = AVCaptureDevice

  do { input = try AVCaptureDeviceInput(device: camera) } catch { return }

  output = AVCaptureStillImageOutput()
  output.outputSettings = [ AVVideoCodecKey: AVVideoCodecJPEG ]

  guard session.canAddInput(input)
     && session.canAddOutput(output) else { return }


  previewLayer = AVCaptureVideoPreviewLayer(session: session)

  previewLayer!.videoGravity = AVLayerVideoGravityResizeAspect
  previewLayer!.connection?.videoOrientation = .Portrait




How to solve the problem:

Solution 1:

On my 6S the default camera focus mode is .ContinuousAutoFocus, which continuously focuses on whatever is taking up most of the camera’s field of vision. Sounds like that’s what you want.

You can check if your camera supports auto focus like so:


and if it’s not already set, set it like so:

try! camera.lockForConfiguration()
camera.focusMode = .ContinuousAutoFocus

Solution 2:

Here is what I did:

 //get instance of phone camera
 let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
 //try to enable auto focus
 if(captureDevice!.isFocusModeSupported(.continuousAutoFocus)) {
     try! captureDevice!.lockForConfiguration()
     captureDevice!.focusMode = .continuousAutoFocus

Hope this helps!