This is the sample code for Core ML using ResNet50 provided by Apple.
ResNet50 can categorize the input image to 1000 pre-trained categories.
What's more, this includes a sample code for coremltools converting keras model to mlmodel.
guard let image = imageView.image, let ref = image.buffer() else {
return
}
do {
// predict
let output = try model.prediction(image: ref)
print(output.classLabel)
print(output.classLabelProbs)
} catch {
print(error)
}