iOS Facial Recognition Continuous Learning

I was tasked to find the best way to create a facial recognition feature on an app with machine learning. This feature will be used to clock employees into the app. The feature will support...

• multiple users per device.

• continuous training (so when the mlmodel recognizes someone, it will send new images to the model on the back-end and train the model with the new recently taken images)

• updates new classes (when a new user comes along and wants to use the app, the app will take pictures of them, send those images to the model training program on the back-end which will train the mlmodel to recognize the new user)

  • sends the newly updated models to other devices in the same store so they will recognize the employees as well

What I've tried.

• I've tinkered with on-device training and Knn. But from what I understand on-device training will not work for this, because the on-device training models can only have up to 10 classes and knn isn't giving very accurate results...at all

• Manual training and re-training with the createML. This is when I...

  1. train a model with createML on my mac
  2. download the model to the app with URLSession
  3. add a new user with the app or take updated pictures of old users
  4. send the images of the new user/updated old user to createML on my mac
  5. create a whole new model with all the images I've ever taken of all the users
  6. repeat steps 2-5 forever

  This works just fine but is unbelievably expensive, time-consuming, and unfeasible for the number of eventual users the app will have, to do over and over again.

  I'm still very new to machine learning and I feel like I'm going about this the wrong way. I would just like to see if anyone knows of a better/more efficient method of continuous learning so the model will remember what it's learned previously and I can just add new classes or images to it with createML... or if someone could point me in the right direction.

Take a look at Turi Create -- also from Apple: https://github.com/apple/turicreate

It can do everything Create ML does, but is in python and programmable, so you could automate the whole process on your backend. If you know how to do it in CreateML, you will find Turi Create easy to pick up.