Identifying Faces through Azure Functions Using Face API

00-environment-variables.cs

var sasToken = Environment.GetEnvironmentVariable("Blob__SasToken");
var containerName = Environment.GetEnvironmentVariable("Blob__Container");
var personGroup = Environment.GetEnvironmentVariable("Blob__PersonGroup");
var numberOfPhotos = Convert.ToInt32(Environment.GetEnvironmentVariable("Blob__NumberOfPhotos"));

var tableName = Environment.GetEnvironmentVariable("Table__Name");

var authKey = Environment.GetEnvironmentVariable("Face__AuthKey");
var endpoint = Environment.GetEnvironmentVariable("Face__Endpoint");
var confidence = Convert.ToDouble(Environment.GetEnvironmentVariable("Face__Confidence"));

01-get-images.cs

var client = new CloudBlobClient();

var container = client.GetContainerReference(containerName);
await container.CreateIfNotExistsAsync().ConfigureAwait(false);

var segment = await container.ListBlobsSegmentedAsync($"{personGroup}/", true, BlobListingDetails.Metadata, numberOfPhotos, null, null, null)
                             .ConfigureAwait(false);

var images = segment.Results.Select(p => (CloudBlockBlob)p).ToList();

if (images.Count < numberOfPhotos)
{
    var uploaded = DO_IMAGE_UPLOAD();

    return new CreatedResult(uploaded.Uri, $"Need {numberOfPhotos - blobs.Count} more photo(s).");
}

02-detect-face.cs

var credentials = new ApiKeyServiceClientCredentials(authKey);
var client = new FaceClient(credentials) { Endpoint = endpoint };

var url = $"{face.Uri.AbsoluteUri}{sasToken}";
var faces = await client.Face
                        .DetectWithUrlAsync(url, recognitionModel: RecognitionModel.Recognition01)
                        .ConfigureAwait(false);

if (faces.Count != 1)
{
    return new BadRequestObjectResult("Too many faces or no face detected");
}

03-train-faces-1.cs

var personGroupId = Guid.NewGuid().ToString();

var client = new CloudTableClient();
var table = client.GetTableReference(tableName);
await table.CreateIfNotExistsAsync().ConfigureAwait(false);

var entity = new FaceEntity(personGroup, personGroupId);
var operation = TableOperation.InsertOrReplace(entity);
await table.ExecuteAsync(operation).ConfigureAwait(false);

03-train-faces-2.cs

var credentials = new ApiKeyServiceClientCredentials(authKey);
var client = new FaceClient(credentials) { Endpoint = endpoint };

await client.PersonGroup
            .CreateAsync(entity.PersonGroupId, entity.PersonGroup, recognitionModel: RecognitionModel.Recognition01)
            .ConfigureAwait(false);

var person = await client.PersonGroupPerson
                         .CreateAsync(entity.PersonGroupId, entity.PersonGroup)
                         .ConfigureAwait(false);

entity.PersonId = person.PersonId.ToString();

03-train-faces-3.cs

var credentials = new ApiKeyServiceClientCredentials(authKey);
var client = new FaceClient(credentials) { Endpoint = endpoint };

var faceIds = new List<string>();
foreach (var face in faces)
{
    var url = $"{face.Uri.AbsoluteUri}{sasToken}";

    var added = await client.PersonGroupPerson
                            .AddFaceFromUrlAsync(entity.PersonGroupId, person.PersonId, url, face.Name)
                            .ConfigureAwait(false);

    var filename = face.Name
                       .Replace($"{personGroup}/", string.Empty)
                       .Replace(".png", string.Empty);

    faceIds.Add(filename);
}

entity.FaceIds = string.Join(",", faceIds);

03-train-faces-4.cs

var credentials = new ApiKeyServiceClientCredentials(authKey);
var client = new FaceClient(credentials) { Endpoint = endpoint };

await client.PersonGroup
            .TrainAsync(entity.PersonGroupId)
            .ConfigureAwait(false);

while (true)
{
    await Task.Delay(1000);
    var trainingStatus = await client.PersonGroup
                                     .GetTrainingStatusAsync(entity.PersonGroupId)
                                     .ConfigureAwait(false);
    if (trainingStatus.Status == TrainingStatusType.Succeeded)
    {
        break;
    }
}

04-identify-face.cs

var credentials = new ApiKeyServiceClientCredentials(authKey);
var client = new FaceClient(credentials) { Endpoint = endpoint };

var faces = DO_FACE_DETECTION();
var detected = faces.Select(p => p.FaceId.Value).ToList();

var identified = await client.Face
                             .IdentifyAsync(detected, entity.PersonGroupId)
                             .ConfigureAwait(false);

entity.Confidence = identified.First().Candidates.First().Confidence;

05-confirm-identification.cs

// var confidence = Convert.ToDouble(Environment.GetEnvironmentVariable("Face__Confidence"));

if (entity.Confidence < confidence)
{
    return new BadRequestObjectResult($"Face not identified: {entity.Confidence:0.00}");
}

return new OkObjectResult($"Face identified: {entity.Confidence:0.00}");