65 lines
2.0 KiB
Swift
65 lines
2.0 KiB
Swift
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//
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// VisionHandler.swift
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// CapFinder
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//
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// Created by User on 12.02.18.
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// Copyright © 2018 User. All rights reserved.
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//
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import Foundation
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import Vision
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import CoreML
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import UIKit
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/// Recognise categories in images
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class Classifier: Logger {
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static let userDefaultsKey = "classifier.version"
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let model: VNCoreMLModel
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init(model: VNCoreMLModel) {
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self.model = model
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}
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/**
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Classify an image
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- Parameter image: The image to classify
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- Note: This method should not be scheduled on the main thread.
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*/
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func recognize(image: UIImage, completion: @escaping (_ matches: [Int: Float]?) -> Void) {
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guard let ciImage = CIImage(image: image) else {
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error("Unable to create CIImage")
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completion(nil)
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return
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}
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let orientation = CGImagePropertyOrientation(image.imageOrientation)
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let handler = VNImageRequestHandler(ciImage: ciImage, orientation: orientation)
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let request = VNCoreMLRequest(model: model) { request, error in
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let matches = self.process(request: request, error: error)
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completion(matches)
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}
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request.imageCropAndScaleOption = .centerCrop
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do {
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try handler.perform([request])
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} catch {
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self.error("Failed to perform classification: \(error)")
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}
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}
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private func process(request: VNRequest, error: Error?) -> [Int : Float]? {
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if let e = error {
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self.error("Unable to classify image: \(e.localizedDescription)")
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return nil
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}
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guard let result = request.results as? [VNClassificationObservation] else {
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self.error("Invalid classifier result: \(String(describing: request.results))")
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return nil
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}
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let matches = result.reduce(into: [:]) { $0[Int($1.identifier)!] = $1.confidence }
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log("Classifed image with \(matches.count) classes")
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return matches
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}
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}
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