VNDetectFaceRectanglesRequest 人脸检测

Question

我正在使用Vision框架来处理图像。我正在使用的函数运行良好，在完成处理程序中不返回任何错误，但结果为空。

这是我的功能：

 func recognizeImage() {
        let request = VNDetectFaceRectanglesRequest { (res: VNRequest, error: Error?) in
            print("Reuslt : \(res.accessibilityActivationPoint)")
        }

        if let cgContet = image.image.cgImage  {
            let handler = VNImageRequestHandler(cgImage: cgContet)
            try? handler.perform([request])
        }
    }

函数的结果是：

Reuslt : (0.0, 0.0)

Answer 1

如果你想检测人脸并在每个人脸上画一个矩形，试试这个：

let request=VNDetectFaceRectanglesRequest{request, error in
    var final_image=UIImage(named: image_to_process)

    if let results=request.results as? [VNFaceObservation]{
        print(results.count, "faces found")
        for face_obs in results{
          //draw original image
          UIGraphicsBeginImageContextWithOptions(final_image.size, false, 1.0)
          final_image.draw(in: CGRect(x: 0, y: 0, width: final_image.size.width, height: final_image.size.height))

          //get face rect
          var rect=face_obs.boundingBox
          let tf=CGAffineTransform.init(scaleX: 1, y: -1).translatedBy(x: 0, y: -final_image.size.height)
          let ts=CGAffineTransform.identity.scaledBy(x: final_image.size.width, y: final_image.size.height)
          let converted_rect=rect.applying(ts).applying(tf)    

          //draw face rect on image
          let c=UIGraphicsGetCurrentContext()!
          c.setStrokeColor(UIColor.red.cgColor)
          c.setLineWidth(0.01*final_image.size.width)
          c.stroke(converted_rect)

          //get result image
          let result=UIGraphicsGetImageFromCurrentImageContext()
          UIGraphicsEndImageContext()

          final_image=result!
        }
    }

    //display final image
    DispatchQueue.main.async{
        self.image_view.image=final_image
    }
}


guard let ciimage=CIImage(image:image_to_process) else{
  fatalError("couldn't convert uiimage to ciimage")
}

let handler=VNImageRequestHandler(ciImage: ciimage)
DispatchQueue.global(qos: .userInteractive).async{
    do{
        try handler.perform([request])
    }catch{
        print(error)
    }
}