在 Swift 中设置 CoreML 模型 - 图像分类器

Posted 2023-03-27

【中文标题】在 Swift 中设置 CoreML 模型 - 图像分类器

【英文标题】：Setting up a CoreML Model in Swift - Image Classifier

【发布时间】：2020-06-30 19:54:55

【问题描述】：

我已经训练了一个模型来区分恶性和良性皮肤病变，以潜在地检测患者是否患有皮肤癌，并将我的 keras 模型转换为 coreML。现在，我正在尝试使用 swift（通过 Xcode）将我的模型应用于 ios 应用程序，而我完全没有经验（仍在通过反复试验学习）。

目前我正试图通过一个简单的应用程序让模型工作，该应用程序只从手机的摄像头获取图像以获取预测的标签作为输出，但我非常坚持让摄像头实际工作来做到这一点。

import UIKit
import CoreML
import Vision
import Social

@UIApplicationMain
class ViewControl: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UIApplicationDelegate 

    @IBOutlet weak var imageView: UIImageView!
    var classificationResults : [VNClassificationObservation] = []

    let imagePicker = UIImagePickerController()

    override func viewDidLoad() 
        super.viewDidLoad()

        imagePicker.delegate = self

    

    func detect(image: CIImage) 

        // Load the ML model through its generated class
        guard let model = try? VNCoreMLModel(for: weights_skin_cancer().model) else 
            fatalError("can't load ML model")
        

        let request = VNCoreMLRequest(model: model)  request, error in
            guard let results = request.results as? [VNClassificationObservation],
                let topResult = results.first
                else 
                    fatalError("unexpected result type from VNCoreMLRequest")
                

                if topResult.identifier.contains("malignant") 
                    DispatchQueue.main.async 
                        self.navigationItem.title = "mal!"
                        self.navigationController?.navigationBar.barTintColor = UIColor.green
                        self.navigationController?.navigationBar.isTranslucent = false


                    
                
                else 
                    DispatchQueue.main.async 
                        self.navigationItem.title = "benign!"
                        self.navigationController?.navigationBar.barTintColor = UIColor.red
                        self.navigationController?.navigationBar.isTranslucent = false

                    
                


        

        let handler = VNImageRequestHandler(ciImage: image)

        do  try handler.perform([request]) 
        catch  print(error) 



    


    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) 


        if let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage 

            imageView.image = image

            imagePicker.dismiss(animated: true, completion: nil)


            guard let ciImage = CIImage(image: image) else 
                fatalError("couldn't convert uiimage to CIImage")
            

            detect(image: ciImage)

        
    


    @IBAction func cameraTapped(_ sender: Any) 

        imagePicker.sourceType = .camera
        imagePicker.allowsEditing = false

        present(imagePicker, animated: true, completion: nil)
    

这也是用于将我的模型转换为 coreML 的代码以供参考：

import coremltools

output_labels = ['benign', 'malignant']
scale = 1/255.
coreml_model = coremltools.converters.keras.convert('/Users/Grampun/Desktop/ISIC-Archive-Downloader-master/trained_models/lr_0.00006-400_DS-20_epochs/weights.best.from_scratch.6.hdf5',
                                                    input_names='image',
                                                    image_input_names='image',
                                                    output_names='output',
                                                    class_labels=output_labels,
                                                    image_scale=scale)

coreml_model.author = 'Jack Bugeja'
coreml_model.short_description = 'Model used to identify between benign and malignant skin lesions'

coreml_model.input_description['image'] = 'Dermascopic image of skin lesion to evaluate'
coreml_model.input_description['output'] = 'Malignant/Benign'

coreml_model.save(
    '/Users/Grampun/Desktop/ISIC-Archive-Downloader-master/trained_models/model_for_ios/lr_0.00006-400_DS-20_epochs/weights_skin_cancer.mlmodel')

任何一般的帮助将不胜感激。 谢谢！

【问题讨论】：

你问的实际问题是什么？

@MatthijsHollemans 抱歉，如果不清楚，我在问如何让相机工作 - 我的代码中的什么导致我的相机一旦按下就无法激活。

【参考方案1】：

打开相机：

@IBAction func cameraTapped(_ sender: Any) 
    let controller = UIImagePickerController()
    controller.sourceType = .camera
    controller.mediaTypes = ["public.image"]
    controller.allowsEditing = false
    controller.delegate = self
    present(controller, animated: true)

将YourModel.mlmodel 添加到您的项目中。

在didFinishPickingMediaWithInfo 中添加此代码：

if let imageURL = info[.imageURL] as? URL 
    if let image = UIImage(contentsOfFile: imageURL.absoluteString) 
        self.getPrediction(image)
    

添加这个以获得预测：

func getPrediction(_ image: UIImage) 
    let model = YourModel()

    guard let pixelBuffer = buffer(from: image) else  return 
    guard let prediction = try? model.prediction(image: pixelBuffer) else  return 

    print(prediction.classLabel) // Most likely image category as string value

使用此辅助函数从您的UIImage 生成一个CVPixelBuffer，您需要在getPrediction() 中使用它

func buffer(from image: UIImage) -> CVPixelBuffer? 
    let attrs = [kCVPixelBufferCGImageCompatibilityKey: kCFBooleanTrue, kCVPixelBufferCGBitmapContextCompatibilityKey: kCFBooleanTrue] as CFDictionary
    var pixelBuffer : CVPixelBuffer?
    let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(image.size.width), Int(image.size.height), kCVPixelFormatType_32ARGB, attrs, &pixelBuffer)
    guard (status == kCVReturnSuccess) else 
        return nil
    

    CVPixelBufferLockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags(rawValue: 0))
    let pixelData = CVPixelBufferGetBaseAddress(pixelBuffer!)

    let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
    let context = CGContext(data: pixelData, width: Int(image.size.width), height: Int(image.size.height), bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer!), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.noneSkipFirst.rawValue)

    context?.translateBy(x: 0, y: image.size.height)
    context?.scaleBy(x: 1.0, y: -1.0)

    UIGraphicsPushContext(context!)
    image.draw(in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
    UIGraphicsPopContext()
    CVPixelBufferUnlockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags(rawValue: 0))

    return pixelBuffer

【讨论】：

感谢您的回复。不幸的是，我目前无法打开相机。

@Grampun 我编辑了我的答案，看看是否能解决你的问题

您可能还需要为您的应用的 Info.plist 添加权限，否则将无法访问相机。在 Xcode 的调试输出窗格中应该有关于此的错误消息。

@MatthijsHollemans 你是对的。需要在Info.plist中添加Privacy - Camera Usage Description

@MatthijsHollemans 将权限添加到 .plist 但相机仍然无法正常工作。将尝试更多地工作以希望它能够正常工作......