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Image difference from VNDocumentCameraViewController and AVCaptureStillImageOutput?

Friends, please tell me what is the difference between images obtained from VNDocumentCameraViewController and AVCaptureStillImageOutput.

I use it for text recognition using VNRecognizeTextRequest, and when I get an image from VNDocumentCameraViewController, the text is recognized perfectly, and when I just take a photo from AVCaptureStillImageOutput, the text does not want to be recognized. Thanks a lot.

Solution

  • I had the same problem and in my case passing the orientation to VNImageRequestHandler solved it.

    You can get an UIImage.Orientation from an UIImage by using the imageOrientation property.

    VNImageRequestHandler expects a CGImagePropertyOrientation so you'll have to convert them with something like:

    func convert(orientation: UIImage.Orientation) -> CGImagePropertyOrientation {
    switch orientation {
    case .up: return .up
    case .upMirrored: return .upMirrored
    case .down: return .down
    case .downMirrored: return .downMirrored
    case .left: return .left
    case .leftMirrored: return .leftMirrored
    case .right: return .right
    case .rightMirrored: return .rightMirrored
    @unknown default: return .up
    }
}

    Also AVCaptureStillImageOutput is deprecated you should use AVCapturePhotoOutput if you can.