This is a sample Xamarin app showing how to use the Azure Cognitive Services FaceAPIs to detect and analyse faces in a photo.
Read more on how this works and how to use it from this blog post.
From the Azure Portal, select Create a resource, search for "Face", and select Face from the AI + Machine Learning category. The click Create.
Enter a name for this resource, select your subscription and the location nearest to you. For the pricing tier, there is a free tier called F0 that gives you 30,000 calls per month at a rate of no more than 20 per minute, and you can have one face resource per subscription with this tier. After this there is a paid tier limited to 10 calls per second and you pay per 1,000 calls - at the time of writing this is US$0.25 per 1,000 calls.
Choose a resource group, or create a new one and click Create. Once it has been created, head to it and grab an API key from Resource Management->Keys, and the endpoint from the Overview blade.
The Face Finder app is pretty complete, all you need to do is update the ApiKeys.cs file with your API key and endpoint. For the FaceApiKey, copy yours and paste it in. For the FaceApiEndpoint, paste the value for the endpoint, removing everything past microsoft.com. For example, for me the endpoint shown in the Azure portal is https://westeurope.api.cognitive.microsoft.com/face/v1.0, so I would set the endpoint to https://westeurope.api.cognitive.microsoft.com.
If you get a Not Found exception, then check your endpoint - this exception is thrown if you don't remove everything past
microsoft.com.
Once you have done this, build and run the app. When it loads, tap the Take photo button and take a picture of one or more faces. The app will then show a list of all the faces detected, describing them using the detected age and gender. Tap on a face in the list to see more details, including if that person is smiling, if they are wearing glasses, what hair, facial hair and makeup they have, and their emotion.