public static async Task <SimilarPersistedFace> FindSimilarPersistedFaceAsync(Func <Task <Stream> > imageStreamCallback, Guid faceId, Face face)
{
if (faceLists == null)
{
await Initialize();
}
Tuple <SimilarPersistedFace, string> bestMatch = null;
bool foundMatch = false;
foreach (var faceListId in faceLists.Keys)
{
try
{
SimilarPersistedFace similarFace = (await FaceServiceHelper.FindSimilarAsync(faceId, faceListId))?.FirstOrDefault();
if (similarFace == null)
{
continue;
}
foundMatch = true;
if (bestMatch != null)
{
// We already found a match for this face in another list. Replace the previous one if the new confidence is higher.
if (bestMatch.Item1.Confidence < similarFace.Confidence)
{
bestMatch = new Tuple <SimilarPersistedFace, string>(similarFace, faceListId);
}
}
else
{
bestMatch = new Tuple <SimilarPersistedFace, string>(similarFace, faceListId);
}
}
catch (Exception e)
{
// Catch errors with individual face lists so we can continue looping through all lists. Maybe an answer will come from
// another one.
ErrorTrackingHelper.TrackException(e, "Face API FindSimilarAsync error");
}
}
if (!foundMatch)
{
// If we are here we didnt' find a match, so let's add the face to the first FaceList that we can add it to. We
// might create a new list if none exist, and if all lists are full we will delete the oldest face list (based on when we
// last matched anything on it) so that we can add the new one.
double maxAngle = 30;
if (face.FaceAttributes.HeadPose != null &&
(Math.Abs(face.FaceAttributes.HeadPose.Yaw) > maxAngle ||
Math.Abs(face.FaceAttributes.HeadPose.Pitch) > maxAngle ||
Math.Abs(face.FaceAttributes.HeadPose.Roll) > maxAngle))
{
// This isn't a good frontal shot, so let's not use it as the primary example face for this person
return(null);
}
if (!faceLists.Any())
{
// We don't have any FaceLists yet. Create one
string newFaceListId = Guid.NewGuid().ToString();
await FaceServiceHelper.CreateFaceListAsync(newFaceListId, "ManagedFaceList", FaceListsUserDataFilter);
faceLists.Add(newFaceListId, new FaceListInfo {
FaceListId = newFaceListId, LastMatchTimestamp = DateTime.Now
});
}
AddPersistedFaceResult addResult = null;
bool failedToAddToNonFullList = false;
foreach (var faceList in faceLists)
{
if (faceList.Value.IsFull)
{
continue;
}
try
{
addResult = await FaceServiceHelper.AddFaceToFaceListAsync(faceList.Key, imageStreamCallback, face.FaceRectangle);
break;
}
catch (Exception ex)
{
if (ex is FaceAPIException && ((FaceAPIException)ex).ErrorCode == "403")
{
// FaceList is full. Continue so we can try again with the next FaceList
faceList.Value.IsFull = true;
continue;
}
else
{
failedToAddToNonFullList = true;
break;
}
}
}
if (addResult == null && !failedToAddToNonFullList)
{
// We were not able to add the face to an existing list because they were all full.
// If possible, let's create a new list now and add the new face to it. If we can't (e.g. we already maxed out on list count),
// let's delete an old list, create a new one and add the new face to it.
if (faceLists.Count == 64)
{
// delete oldest face list
var oldestFaceList = faceLists.OrderBy(fl => fl.Value.LastMatchTimestamp).FirstOrDefault();
faceLists.Remove(oldestFaceList.Key);
await FaceServiceHelper.DeleteFaceListAsync(oldestFaceList.Key);
}
// create new list
string newFaceListId = Guid.NewGuid().ToString();
await FaceServiceHelper.CreateFaceListAsync(newFaceListId, "ManagedFaceList", FaceListsUserDataFilter);
faceLists.Add(newFaceListId, new FaceListInfo {
FaceListId = newFaceListId, LastMatchTimestamp = DateTime.Now
});
// Add face to new list
addResult = await FaceServiceHelper.AddFaceToFaceListAsync(newFaceListId, imageStreamCallback, face.FaceRectangle);
}
if (addResult != null)
{
bestMatch = new Tuple <SimilarPersistedFace, string>(new SimilarPersistedFace {
Confidence = 1, PersistedFaceId = addResult.PersistedFaceId
}, null);
}
}
return(bestMatch?.Item1);
}