I am using the following to detect rectangles in this image: https://richardzhaodesign.files.wordpress.com/2015/02/order-final.jpg?w=300&h=300
import UIKit
import Vision
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
guard let image = UIImage(named: "sample2") else { return }
let imageView = UIImageView(image: image)
imageView.contentMode = .scaleAspectFit
let scaledHeight = view.frame.width / image.size.width * image.size.height
imageView.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: scaledHeight)
imageView.backgroundColor = .blue
view.addSubview(imageView)
let request = VNDetectRectanglesRequest { (req, err) in
if let err = err {
print("Failed to detect faces:", err)
return
}
req.results?.forEach({ (res) in
print("one")
DispatchQueue.main.async {
guard let rectangleObservation = res as? VNRectangleObservation else { return }
let x = self.view.frame.width * rectangleObservation.boundingBox.origin.x
let height = scaledHeight * rectangleObservation.boundingBox.height
let y = scaledHeight * (1 - rectangleObservation.boundingBox.origin.y) - height
let width = self.view.frame.width * rectangleObservation.boundingBox.width
let redView = UIView()
redView.layer.borderColor = UIColor.red.cgColor
redView.layer.borderWidth = 5
redView.frame = CGRect(x: x, y: y, width: width, height: height)
self.view.addSubview(redView)
}
})
}
guard let cgImage = image.cgImage else { return }
DispatchQueue.global(qos: .background).async {
let handler = VNImageRequestHandler(cgImage: cgImage, options: [:])
do {
try handler.perform([request])
} catch let reqErr {
print("Failed to perform request:", reqErr)
}
}
}
}
My question is why does this not recognize two squares. I have seen other codes recognize multiple rectangles, but mine will always only recognize one. I am sure that it is not that the Vision framework is not capable of recognizing the other one with high accuracy, just that I am missing something in my code. Thanks you.
You must set the maximumObservations property of your VNDetectRectanglesRequest
. The default value is 1, which is why you are only getting 1 result.
For example:
let request = VNDetectRectanglesRequest { (req, err) in
// Your completion handler code
}
request.maximumObservations = 2