SALE: Save 50% on all my books and bundles >>

How to detect documents using VNDocumentCameraViewController

Swift version: 5.1

Paul Hudson    @twostraws   

iOS 13.0 introduced a new micro-framework called VisionKit, which is specifically designed to make it possible to scan documents like Notes does.

You can then Vision OCR to scan the text if you want, but by default VNDocumentCameraViewController just gives you images of each page.

To get started:

  1. Import VisionKit.
  2. Make some type (such as your view controller) conform to the VNDocumentCameraViewControllerDelegate protocol so you can handle delegate callbacks.
  3. Create and present an instance of VNDocumentCameraViewController, setting its delegate property to whatever should be notified when a scan completes.
  4. Present the document scanner as normal, then wait for feedback.

So, something like this:

let vc = VNDocumentCameraViewController()
vc.delegate = self
present(vc, animated: true)

Once the scan completes your delegate will get called with the document, like this:

func documentCameraViewController(_ controller: VNDocumentCameraViewController, didFinishWith scan: VNDocumentCameraScan) {
    print("Found \(scan.pageCount)")

    for i in 0 ..< scan.pageCount {
        let img = scan.imageOfPage(at: i)
        // ... your code here
    }
}

The result of imageOfPage(at:) is a UIImage, so you’ll need to replace “your code here” with whatever you want to do with your images.

Hacking with Swift is sponsored by Instabug

SPONSORED Catch bugs as soon as they happen and know exactly why a crash occurred by integrating Instabug's SDK in one minute. You will automatically receive device data, network logs, and reproduction steps with every bug and crash report.

Learn more and get started for free

Sponsor Hacking with Swift and reach the world's largest Swift community!

Snapthread is a casual video editor and slideshow maker that makes discovering, compiling and sharing your favorite memories effortless.

Available from iOS 13.0

Similar solutions…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 3.8/5