/// <summary>
/// Delegate to define the actions taken upon the photo capture of the camera class.
/// This one uses the memory stream of the photo capture to identify the faces in the iamge, using the local face detection instance.
/// </summary>
/// <param name="memoryStream">The memory stream containing the captured image.</param>
private async Task IdentifyFaces_Delegate(MemoryStream memoryStream)
{
var faces = await faceDetection.DetectFaces(memoryStream);
if (faces.Length > 0)
{
// you could call the face API once for all faces together
// but there's no way to map the found persons to the detected face rectangles
// so we have to call the API per detected face rectangle
foreach (var face in faces)
{
try
{
var persons = await faceDetection.IdentifyFace(new[] { face });
// set identities when there is at least one person within the viewport
if (persons.Count > 0)
{
var person = persons.FirstOrDefault();
if (person != null)
{
identityInterpolation.IdentifiedFace(face, person);
}
}
// remove the current identity when there is no person identified
else if (persons.Count == 0)
{
currentIdentity = null;
}
}
catch (FaceAPIException)
{
// if the person group is not yet trained or face identification fails for any other reason, continue
}
}
// after adding new identified faces, switch to interact with the possibly new person within the viewport,
// so make sure to get the new largest face object (event won't be fired again!)
var trackedIdentity = identityInterpolation.GetLargestFace();
if (trackedIdentity != null)
{
// if there is no current identity, handle the new person as found
if (currentIdentity == null)
{
OnPersonFound(trackedIdentity);
}
else if (currentIdentity != null)
{
// if there is an identity currently, check if it has actually changed before calling person found
if (currentIdentity.PersonId != trackedIdentity.PersonId)
{
OnPersonFound(trackedIdentity);
}
}
}
}
}