[D-0] �Vision를 통해 영수증 스캔 기능 구현 (#91)

* feat: DocumentScanner scanDocument() 구현

* feat: `editImageWithScanResult()` 메서드 구현

* feat: 문서 스캔 기능 구현 및 maskLayer 추가

* fix: CreateOCRLedgerVC 메모리 누수 해결

* fix: 영수증 촬영 시 captureImageView에 원본 이미지가 표현되도록 수정

* chore: CVImageBuffer extension DocumentScanner로 이동

* refactor: transformBoundingBox 네이밍 및 코드 변경

- transformBoundingBox -> transformVisionToIOS 네이밍 변경
- CGAffineTransform -> CGRect로 변경

* refactor: editImageWithScanResult 반환 타입 변경

- CGImage -> CIImage

* refactor: scanDocument 파라미터 및 request 설정값 변경

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: maxim-lobanov/setup-xcode@v1
         with:
-          xcode-version: 15.4.0
+          xcode-version: latest-stable
       - uses: shimataro/ssh-key-action@v2
         with: 
           key: ${{ secrets.SSH_KEY }}

Projects/App/Project.swift

@@ -8,7 +8,7 @@ let project = Project(
   ),
   settings: .settings(
     base: .init()
-      .marketingVersion("1.4.0")
+      .marketingVersion("1.4.1")
       .swiftVersion("5.7")
       .currentProjectVersion("1")
       .appleGenericVersioningSystem(),

Projects/Feature/Ledger/Sources/Scene/Ledger/Creaters/Scan/Components/CameraView.swift

@@ -5,8 +5,21 @@ import Core
 
 import RxSwift
 
+protocol CameraViewDelegate: AnyObject {
+  func cameraView(_ cameraView: CameraView, scanResult result: UIImage, originalImage image: UIImage)
+}
+
 final class CameraView: UIView {
-  weak var delegate: AVCapturePhotoCaptureDelegate?
+  weak var delegate: CameraViewDelegate?
+
+  private var scanFailedCount = 0 {
+    didSet {
+      if scanFailedCount > 10, !maskLayer.isHidden {
+        maskLayer.isHidden = true
+        scanFailedCount = 0
+      }
+    }
+  }
 
   private let captureSession: AVCaptureSession = {
     let session = AVCaptureSession()
@@ -15,6 +28,10 @@ final class CameraView: UIView {
   }()
 
   private let stillImageOutput = AVCapturePhotoOutput()
+  private let videoDataOutput = AVCaptureVideoDataOutput()
+  private let documentScanner = DocumentScanner()
+
+  private var maskLayer = CAShapeLayer()
 
   private let videoPreviewLayer: AVCaptureVideoPreviewLayer = {
     let layer = AVCaptureVideoPreviewLayer()
@@ -70,6 +87,18 @@ final class CameraView: UIView {
       captureSession.addOutput(stillImageOutput)
     }
 
+    if captureSession.canAddOutput(videoDataOutput) {
+      self.videoDataOutput.setSampleBufferDelegate(self, queue: .global())
+      captureSession.addOutput(videoDataOutput)
+
+      guard let connection = self.videoDataOutput.connection(with: AVMediaType.video),
+            connection.isVideoOrientationSupported else { return }
+
+      connection.videoOrientation = .portrait
+    }
+
+    self.layer.addSublayer(maskLayer)
+
     // 프리뷰 레이어 설정
     videoPreviewLayer.session = captureSession
 
@@ -100,11 +129,44 @@ final class CameraView: UIView {
 
   var takePhoto: Binder<Void> {
     return Binder(self) { owner, _ in
-      guard let delegate = owner.delegate else {
-        fatalError("델리게이트를 설정하세요.")
-      }
       let settings = AVCapturePhotoSettings()
-      owner.stillImageOutput.capturePhoto(with: settings, delegate: delegate)
+      owner.stillImageOutput.capturePhoto(with: settings, delegate: owner)
+    }
+  }
+}
+
+extension CameraView: AVCaptureVideoDataOutputSampleBufferDelegate {
+  func captureOutput(_ output: AVCaptureOutput,didOutput sampleBuffer: CMSampleBuffer,from connection: AVCaptureConnection) {
+    guard let buffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return }
+
+    Task {
+      guard let scanRect = try await documentScanner.scanDocument(imageBuffer: buffer, with: bounds) else {
+        scanFailedCount += 1
+        return
+      }
+      scanFailedCount = 0
+      updateMaskLayer(in: scanRect)
+    }
+  }
+
+  private func updateMaskLayer(in rect: CGRect) {
+    maskLayer.isHidden = false
+    maskLayer.frame = rect
+    maskLayer.cornerRadius = 10
+    maskLayer.borderColor = UIColor.systemBlue.cgColor
+    maskLayer.borderWidth = 1
+    maskLayer.opacity = 1
+  }
+}
+
+extension CameraView: AVCapturePhotoCaptureDelegate {
+  func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
+    Task {
+      guard let imageData = photo.fileDataRepresentation(),
+            let originalImage = UIImage(data: imageData),
+            let result = await documentScanner.editImageWithScanResult(imageData) else { return }
+
+      delegate?.cameraView(self, scanResult: UIImage(ciImage: result), originalImage: originalImage)
     }
   }
 }

Projects/Feature/Ledger/Sources/Scene/Ledger/Creaters/Scan/Model/DocumentScanner.swift

@@ -0,0 +1,74 @@
+import Vision
+import CoreImage
+
+actor DocumentScanner: Sendable {
+  private var recentScanResult: VNRectangleObservation?
+
+  func scanDocument(imageBuffer: CVImageBuffer, with previewSize: CGRect) async throws -> CGRect? {
+    return try await withCheckedThrowingContinuation { [weak self] continuation in
+      guard let self else { continuation.resume(returning: nil); return }
+      let request = VNDetectRectanglesRequest { (request: VNRequest, error: Error?) in
+        guard let results = request.results as? [VNRectangleObservation],
+              let rectangleObservation = results.first else {
+          continuation.resume(returning: nil); return
+        }
+
+        Task {
+          await self.updateRecentScanResult(rectangleObservation)
+          let rect = await self.transformVisionToIOS(rectangleObservation, to: previewSize)
+          continuation.resume(returning: rect)
+        }
+      }
+
+      request.minimumAspectRatio = 0.2
+      request.maximumAspectRatio = 1.0
+      request.minimumConfidence = 0.8
+
+      let handler = VNImageRequestHandler(cvPixelBuffer: imageBuffer, options: [:])
+      do {
+        try handler.perform([request])
+      } catch {
+        continuation.resume(throwing: error)
+      }
+    }
+  }
+
+  func editImageWithScanResult(_ imageData: Data) -> CIImage? {
+    guard let ciImage = CIImage(data: imageData)?.oriented(.right),
+          let recentScanResult else { return nil }
+
+    let topLeft = recentScanResult.topLeft.scaled(to: ciImage.extent.size)
+    let topRight = recentScanResult.topRight.scaled(to: ciImage.extent.size)
+    let bottomLeft = recentScanResult.bottomLeft.scaled(to: ciImage.extent.size)
+    let bottomRight = recentScanResult.bottomRight.scaled(to: ciImage.extent.size)
+
+    return ciImage.applyingFilter("CIPerspectiveCorrection", parameters: [
+      "inputTopLeft": CIVector(cgPoint: topLeft),
+      "inputTopRight": CIVector(cgPoint: topRight),
+      "inputBottomLeft": CIVector(cgPoint: bottomLeft),
+      "inputBottomRight": CIVector(cgPoint: bottomRight),
+    ])
+  }
+
+  private func transformVisionToIOS(_ rectangleObservation: VNRectangleObservation, to previewSize: CGRect) -> CGRect {
+    let visionRect = rectangleObservation.boundingBox
+    return CGRect(
+      origin: CGPoint(x: CGFloat(visionRect.minX * previewSize.width), y: CGFloat((1 - visionRect.maxY) * previewSize.height)),
+      size: CGSize(width: visionRect.width * previewSize.width, height: visionRect.height * previewSize.height)
+    )
+  }
+
+  private func updateRecentScanResult(_ rectangleObservation: VNRectangleObservation) {
+    recentScanResult = rectangleObservation
+  }
+}
+
+private extension CGPoint {
+  func scaled(to size: CGSize) -> CGPoint {
+    return CGPoint(x: self.x * size.width,
+                   y: self.y * size.height)
+  }
+}
+
+extension CVImageBuffer: @unchecked @retroactive Sendable {}
+

Projects/Feature/Ledger/Sources/Scene/Ledger/Creaters/Scan/ScanCreater/CreateOCRLedgerReactor.swift

@@ -14,15 +14,15 @@ final class CreateOCRLedgerReactor: Reactor {
   }
 
   enum Mutation {
-    case setImageData(Data?)
+    case setTake(Bool)
     case setLoading(Bool)
     case setError(MoneyMongError)
     case setDestination(State.Destination)
   }
 
   struct State {
     let agencyId: Int
-    @Pulse var imageData: Data?
+    @Pulse var isTook: Bool = false
     @Pulse var isLoading: Bool = false
     @Pulse var error: MoneyMongError?
     @Pulse var destination: Destination?
@@ -44,32 +44,32 @@ final class CreateOCRLedgerReactor: Reactor {
 
   func mutate(action: Action) -> Observable<Mutation> {
     switch action {
-    case .onAppear:
-        .just(.setImageData(nil))
     case .receiptShoot(let data):
         .concat([
-          .just(.setImageData(data)),
+          .just(.setTake(true)),
           .just(.setLoading(true)),
           requsetOCR(data),
           .just(.setLoading(false))
         ])
     case let .onError(error):
         .just(.setError(error))
+    case .onAppear:
+        .just(.setTake(false))
     }
   }
 
   func reduce(state: State, mutation: Mutation) -> State {
     var newState = state
     newState.error = nil
     switch mutation {
-    case let .setImageData(data):
-      newState.imageData = data
     case let .setLoading(isLoading):
       newState.isLoading = isLoading
     case let .setError(error):
       newState.error = error
     case let .setDestination(destination):
       newState.destination = destination
+    case let .setTake(isTook):
+      newState.isTook = isTook
     }
     return newState
   }

Projects/Feature/Ledger/Sources/Scene/Ledger/Creaters/Scan/ScanCreater/CreateOCRLedgerVC.swift

@@ -184,16 +184,10 @@ final class CreateOCRLedgerVC: UIViewController, View {
       .bind(to: reactor.action)
       .disposed(by: disposeBag)
 
-    reactor.pulse(\.$imageData)
-      .map { $0 != nil ? UIImage(data: $0!) : nil }
-      .bind(to: captureImageView.rx.image)
-      .disposed(by: disposeBag)
-
-    reactor.pulse(\.$imageData)
-      .map { $0 == nil }
+    reactor.pulse(\.$isTook)
       .bind(with: self) { owner, value in
-        owner.captureImageView.isHidden = value
-        owner.guideLabel.isHidden = !value
+        owner.captureImageView.isHidden = !value
+        owner.guideLabel.isHidden = value
       }
       .disposed(by: disposeBag)
 
@@ -217,8 +211,8 @@ final class CreateOCRLedgerVC: UIViewController, View {
           .alert(
             title: error.errorTitle,
             subTitle: error.errorDescription,
-            type: .onlyOkButton({ [weak self] in
-              self?.captureImageView.image = nil
+            type: .onlyOkButton({
+              owner.captureImageView.image = nil
             })
           )
         )
@@ -238,9 +232,11 @@ final class CreateOCRLedgerVC: UIViewController, View {
   }
 }
 
-extension CreateOCRLedgerVC: AVCapturePhotoCaptureDelegate {
-  func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
-    let imageData = photo.fileDataRepresentation()
+extension CreateOCRLedgerVC: CameraViewDelegate {
+  func cameraView(_ cameraView: CameraView, scanResult result: UIImage, originalImage image: UIImage) {
+    captureImageView.image = image
+
+    guard let imageData = result.jpegData(compressionQuality: 1.0) else { return }
     reactor?.action.onNext(.receiptShoot(imageData))
   }
 }