Does Azure face api record person's face?

Question

In azure face api we create a person and add face to person and we can identify same person.

My question is when we add face to person does azure upload and save image on azure or just it stores mathematical attributes of person'a face.

Answer 1

As at January 2020, "no image will be stored".

REF: https://westus.dev.cognitive.microsoft.com/docs/services/563879b61984550e40cbbe8d/operations/563879b61984550f30395236

Hash-keyed, irreversible vector representations of faces are stored, as follows:

• Detection API: 24 hours
• (Large)PersonGroup: persisted until deleted by client

BUT, Azure Cognitive Services reserves the right to use data for service improvements:

Ts&Cs are Section D of https://azure.microsoft.com/en-us/support/legal/cognitive-services-terms

Some technical details:

• The vector representations should/will never be exposed or the models could be reverse-engineered - see e.g. https://blog.floydhub.com/inverting-facial-recognition-models
• There is a HOWTO on vector-embedding creation at e.g. https://machinelearningmastery.com/how-to-develop-a-face-recognition-system-using-facenet-in-keras-and-an-svm-classifier

Answer 2

It depends on what you are doing. If you are running the identify and detect APIs, it will delete after 24 hours: "Will expire 24 hours after detection call." https://learn.microsoft.com/en-us/connectors/faceapi/

If you create a person group and add faces to the person, it adds it in a thing called persisted face ID. This is persistent and will not delete until you delete it

Answer 3

Based off the documentation, it appears the image is stored on Azure - https://dev.projectoxford.ai/docs/services/563879b61984550e40cbbe8d/operations/563879b61984550f30395236

Azure Cognitive Terms of Service suggest they may also keep the file to improve service. See Part D, number 4 - https://azure.microsoft.com/en-us/support/legal/cognitive-services-terms/