Exploring Azure Face API: Facial Landmark Detection and Real-Time Analysis with C#
In today’s world, applications that understand and respond to human facial cues are no longer science fiction—they’re becoming a reality in domains like security, driver monitoring, gaming, and AR/VR. With Azure Face API, developers can leverage powerful cloud-based facial recognition and analysis tools without building complex machine learning models from scratch. In this blog, we’ll explore how to use C# to detect faces, identify key facial landmarks, estimate head pose, track eye and mouth movements, and process real-time video streams. Using OpenCV for visualization, we’ll show how to overlay landmarks, draw bounding boxes, and calculate metrics like Eye Aspect Ratio (EAR) and Mouth Aspect Ratio (MAR)—all in real time. You'll learn to: Set up Azure Face API Detect 27 facial landmarks Estimate head pose (yaw, pitch, roll) Calculate eye aspect ratio (EAR) and mouth openness Draw bounding boxes around features using OpenCV Process real-time video Prerequisites .NET 8 SDK installed Azure subscription with Face API resource Visual Studio 2022 or later Webcam for testing (optional) Basic understanding of C# and computer vision concepts Part 1: Azure Face API Setup 1.1 Install Required NuGet Packages dotnet add package Azure.AI.Vision.Face dotnet add package OpenCvSharp4 dotnet add package OpenCvSharp4.runtime.win 1.2 Create Azure Face API Resource Navigate to Azure Portal Search for "Face" and create a new Face API resource Choose your pricing tier (Free tier: 20 calls/min, 30K calls/month) Copy the Endpoint URL and API Key 1.3 Configure in .NET Application appsettings.json: { "Azure": { "FaceApi": { "Endpoint": "https://your-resource.cognitiveservices.azure.com/", "ApiKey": "your-api-key-here" } } } Initialize Face Client: using Azure; using Azure.AI.Vision.Face; using Microsoft.Extensions.Configuration; public class FaceAnalysisService { private readonly FaceClient _faceClient; private readonly ILogger<FaceAnalysisService> _logger; public FaceAnalysisService(ILogger<FaceAnalysisService> logger, IConfiguration configuration) { _logger = logger; string endpoint = configuration["Azure:FaceApi:Endpoint"]; string apiKey = configuration["Azure:FaceApi:ApiKey"]; _faceClient = new FaceClient(new Uri(endpoint), new AzureKeyCredential(apiKey)); _logger.LogInformation("FaceClient initialized with endpoint: {Endpoint}", endpoint); } } Part 2: Understanding Face Detection Models 2.1 Basic Face Detection public async Task<List<FaceDetectionResult>> DetectFacesAsync(byte[] imageBytes) { using var stream = new MemoryStream(imageBytes); var response = await _faceClient.DetectAsync( BinaryData.FromStream(stream), FaceDetectionModel.Detection03, FaceRecognitionModel.Recognition04, returnFaceId: false, returnFaceAttributes: new FaceAttributeType[] { FaceAttributeType.HeadPose }, returnFaceLandmarks: true, returnRecognitionModel: false ); _logger.LogInformation("Detected {Count} faces", response.Value.Count); return response.Value.ToList(); } Part 3: Facial Landmarks - The 27 Key Points 3.1 Understanding Facial Landmarks 3.2 Accessing Landmarks in Code public void PrintLandmarks(FaceDetectionResult face) { var landmarks = face.FaceLandmarks; if (landmarks == null) { _logger.LogWarning("No landmarks detected"); return; } // Eye landmarks Console.WriteLine($"Left Eye Outer: ({landmarks.EyeLeftOuter.X}, {landmarks.EyeLeftOuter.Y})"); Console.WriteLine($"Left Eye Inner: ({landmarks.EyeLeftInner.X}, {landmarks.EyeLeftInner.Y})"); Console.WriteLine($"Left Eye Top: ({landmarks.EyeLeftTop.X}, {landmarks.EyeLeftTop.Y})"); Console.WriteLine($"Left Eye Bottom: ({landmarks.EyeLeftBottom.X}, {landmarks.EyeLeftBottom.Y})"); // Mouth landmarks Console.WriteLine($"Upper Lip Top: ({landmarks.UpperLipTop.X}, {landmarks.UpperLipTop.Y})"); Console.WriteLine($"Under Lip Bottom: ({landmarks.UnderLipBottom.X}, {landmarks.UnderLipBottom.Y})"); // Nose landmarks Console.WriteLine($"Nose Tip: ({landmarks.NoseTip.X}, {landmarks.NoseTip.Y})"); } 3.3 Visualizing All Landmarks public void DrawAllLandmarks(FaceLandmarks landmarks, Mat frame) { void DrawPoint(FaceLandmarkCoordinate point, Scalar color) { if (point != null) { Cv2.Circle(frame, new Point((int)point.X, (int)point.Y), radius: 3, color: color, thickness: -1); } } // Eyes (Green) DrawPoint(landmarks.EyeLeftOuter, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeLeftInner, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeLeftTop, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeLeftBottom, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeRightOuter, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeRightInner, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeRightTop, new Scalar(0, 255, 0)); DrawPoint(landmarks.EyeRightBottom, new Scalar(0, 255, 0)); // Eyebrows (Cyan) DrawPoint(landmarks.EyebrowLeftOuter, new Scalar(255, 255, 0)); DrawPoint(landmarks.EyebrowLeftInner, new Scalar(255, 255, 0)); DrawPoint(landmarks.EyebrowRightOuter, new Scalar(255, 255, 0)); DrawPoint(landmarks.EyebrowRightInner, new Scalar(255, 255, 0)); // Nose (Yellow) DrawPoint(landmarks.NoseTip, new Scalar(0, 255, 255)); DrawPoint(landmarks.NoseRootLeft, new Scalar(0, 255, 255)); DrawPoint(landmarks.NoseRootRight, new Scalar(0, 255, 255)); DrawPoint(landmarks.NoseLeftAlarOutTip, new Scalar(0, 255, 255)); DrawPoint(landmarks.NoseRightAlarOutTip, new Scalar(0, 255, 255)); // Mouth (Blue) DrawPoint(landmarks.UpperLipTop, new Scalar(255, 0, 0)); DrawPoint(landmarks.UpperLipBottom, new Scalar(255, 0, 0)); DrawPoint(landmarks.UnderLipTop, new Scalar(255, 0, 0)); DrawPoint(landmarks.UnderLipBottom, new Scalar(255, 0, 0)); DrawPoint(landmarks.MouthLeft, new Scalar(255, 0, 0)); DrawPoint(landmarks.MouthRight, new Scalar(255, 0, 0)); // Pupils (Red) DrawPoint(landmarks.PupilLeft, new Scalar(0, 0, 255)); DrawPoint(landmarks.PupilRight, new Scalar(0, 0, 255)); } Part 4: Drawing Bounding Boxes Around Features 4.1 Eye Bounding Boxes /// <summary> /// Draws rectangles around eyes using OpenCV. /// </summary> public void DrawEyeBoxes(FaceLandmarks landmarks, Mat frame) { int boxWidth = 60; int boxHeight = 35; // Calculate Rectangles var leftEyeRect = new Rect((int)landmarks.EyeLeftOuter.X - boxWidth / 2, (int)landmarks.EyeLeftOuter.Y - boxHeight / 2, boxWidth, boxHeight); var rightEyeRect = new Rect((int)landmarks.EyeRightOuter.X - boxWidth / 2, (int)landmarks.EyeRightOuter.Y - boxHeight / 2, boxWidth, boxHeight); // Draw Rectangles (Green in BGR) Cv2.Rectangle(frame, leftEyeRect, new Scalar(0, 255, 0), 2); Cv2.Rectangle(frame, rightEyeRect, new Scalar(0, 255, 0), 2); // Add Labels Cv2.PutText(frame, "Left Eye", new Point(leftEyeRect.X, leftEyeRect.Y - 5), HersheyFonts.HersheySimplex, 0.4, new Scalar(0, 255, 0), 1); Cv2.PutText(frame, "Right Eye", new Point(rightEyeRect.X, rightEyeRect.Y - 5), HersheyFonts.HersheySimplex, 0.4, new Scalar(0, 255, 0), 1); } 4.2 Mouth Bounding Box /// <summary> /// Draws rectangle around mouth region. /// </summary> public void DrawMouthBox(FaceLandmarks landmarks, Mat frame) { int boxWidth = 80; int boxHeight = 50; // Calculate center based on the vertical lip landmarks int centerX = (int)((landmarks.UpperLipTop.X + landmarks.UnderLipBottom.X) / 2); int centerY = (int)((landmarks.UpperLipTop.Y + landmarks.UnderLipBottom.Y) / 2); var mouthRect = new Rect(centerX - boxWidth / 2, centerY - boxHeight / 2, boxWidth, boxHeight); // Draw Mouth Box (Blue in BGR) Cv2.Rectangle(frame, mouthRect, new Scalar(255, 0, 0), 2); // Add Label Cv2.PutText(frame, "Mouth", new Point(mouthRect.X, mouthRect.Y - 5), HersheyFonts.HersheySimplex, 0.4, new Scalar(255, 0, 0), 1); } 4.3 Face Bounding Box /// <summary> /// Draws rectangle around entire face using the face rectangle from API. /// </summary> public void DrawFaceBox(FaceDetectionResult face, Mat frame) { var faceRect = face.FaceRectangle; if (faceRect == null) { return; } var rect = new Rect( faceRect.Left, faceRect.Top, faceRect.Width, faceRect.Height ); // Draw Face Bounding Box (Red in BGR) Cv2.Rectangle(frame, rect, new Scalar(0, 0, 255), 2); // Add Label with dimensions Cv2.PutText(frame, $"Face {faceRect.Width}x{faceRect.Height}", new Point(rect.X, rect.Y - 10), HersheyFonts.HersheySimplex, 0.5, new Scalar(0, 0, 255), 2); } 4.4 Nose Bounding Box /// <summary> /// Draws bounding box around nose using nose landmarks. /// </summary> public void DrawNoseBox(FaceLandmarks landmarks, Mat frame) { // Calculate horizontal bounds from Alar tips int minX = (int)Math.Min(landmarks.NoseLeftAlarOutTip.X, landmarks.NoseRightAlarOutTip.X); int maxX = (int)Math.Max(landmarks.NoseLeftAlarOutTip.X, landmarks.NoseRightAlarOutTip.X); // Calculate vertical bounds from Root to Tip int minY = (int)Math.Min(landmarks.NoseRootLeft.Y, landmarks.NoseTip.Y); int maxY = (int)landmarks.NoseTip.Y; // Create Rect with a 10px padding buffer var noseRect = new Rect( minX - 10, minY - 10, (maxX - minX) + 20, (maxY - minY) + 20 ); // Draw Nose Box (Yellow in BGR) Cv2.Rectangle(frame, noseRect, new Scalar(0, 255, 255), 2); } Part 5: Geometric Calculations with Landmarks 5.1 Calculating Euclidean Distance /// <summary> /// Calculates distance between two landmark points. /// </summary> public static double CalculateDistance(dynamic point1, dynamic point2) { double dx = point1.X - point2.X; double dy = point1.Y - point2.Y; return Math.Sqrt(dx * dx + dy * dy); } 5.2 Eye Aspect Ratio (EAR) Formula /// <summary> /// Calculates the Eye Aspect Ratio (EAR) to detect eye closure. /// </summary> public double CalculateEAR( FaceLandmarkCoordinate top1, FaceLandmarkCoordinate top2, FaceLandmarkCoordinate bottom1, FaceLandmarkCoordinate bottom2, FaceLandmarkCoordinate inner, FaceLandmarkCoordinate outer) { // Vertical distances double v1 = CalculateDistance(top1, bottom1); double v2 = CalculateDistance(top2, bottom2); // Horizontal distance double h = CalculateDistance(inner, outer); // EAR formula: (||p2-p6|| + ||p3-p5||) / (2 * ||p1-p4||) return (v1 + v2) / (2.0 * h); } Simplified Implementation: /// <summary> /// Calculates Eye Aspect Ratio (EAR) for a single eye. /// Reference: "Real-Time Eye Blink Detection using Facial Landmarks" (Soukupová & Čech, 2016) /// </summary> public double ComputeEAR(FaceLandmarks landmarks, bool isLeftEye) { var top = isLeftEye ? landmarks.EyeLeftTop : landmarks.EyeRightTop; var bottom = isLeftEye ? landmarks.EyeLeftBottom : landmarks.EyeRightBottom; var inner = isLeftEye ? landmarks.EyeLeftInner : landmarks.EyeRightInner; var outer = isLeftEye ? landmarks.EyeLeftOuter : landmarks.EyeRightOuter; if (top == null || bottom == null || inner == null || outer == null) { _logger.LogWarning("Missing eye landmarks"); return 1.0; // Return 1.0 (open) to prevent false positives for drowsiness } double verticalDist = CalculateDistance(top, bottom); double horizontalDist = CalculateDistance(inner, outer); // Simplified EAR for Azure 27-point model double ear = verticalDist / horizontalDist; _logger.LogDebug( "EAR for {Eye}: {Value:F3}", isLeftEye ? "left" : "right", ear ); return ear; } Usage Example: var leftEAR = ComputeEAR(landmarks, isLeftEye: true); var rightEAR = ComputeEAR(landmarks, isLeftEye: false); var avgEAR = (leftEAR + rightEAR) / 2.0; Console.WriteLine($"Average EAR: {avgEAR:F3}"); // Open eyes: ~0.25-0.30 // Closed eyes: ~0.10-0.15 5.3 Mouth Aspect Ratio (MAR) /// <summary> /// Calculates Mouth Aspect Ratio relative to face height. /// </summary> public double CalculateMouthAspectRatio(FaceLandmarks landmarks, FaceRectangle faceRect) { double mouthHeight = landmarks.UnderLipBottom.Y - landmarks.UpperLipTop.Y; double mouthWidth = CalculateDistance(landmarks.MouthLeft, landmarks.MouthRight); double mouthOpenRatio = mouthHeight / faceRect.Height; double mouthWidthRatio = mouthWidth / faceRect.Width; _logger.LogDebug( "Mouth - Height ratio: {HeightRatio:F3}, Width ratio: {WidthRatio:F3}", mouthOpenRatio, mouthWidthRatio ); return mouthOpenRatio; } 5.4 Inter-Eye Distance /// <summary> /// Calculates the distance between pupils (inter-pupillary distance). /// </summary> public double CalculateInterEyeDistance(FaceLandmarks landmarks) { return CalculateDistance(landmarks.PupilLeft, landmarks.PupilRight); } /// <summary> /// Calculates distance between inner eye corners. /// </summary> public double CalculateInnerEyeDistance(FaceLandmarks landmarks) { return CalculateDistance(landmarks.EyeLeftInner, landmarks.EyeRightInner); } 5.5 Face Symmetry Analysis /// <summary> /// Analyzes facial symmetry by comparing left and right sides. /// </summary> public FaceSymmetryMetrics AnalyzeFaceSymmetry(FaceLandmarks landmarks) { double centerX = landmarks.NoseTip.X; double leftEyeDistance = CalculateDistance(landmarks.EyeLeftInner, new { X = centerX, Y = landmarks.EyeLeftInner.Y }); double leftMouthDistance = CalculateDistance(landmarks.MouthLeft, new { X = centerX, Y = landmarks.MouthLeft.Y }); double rightEyeDistance = CalculateDistance(landmarks.EyeRightInner, new { X = centerX, Y = landmarks.EyeRightInner.Y }); double rightMouthDistance = CalculateDistance(landmarks.MouthRight, new { X = centerX, Y = landmarks.MouthRight.Y }); return new FaceSymmetryMetrics { EyeSymmetryRatio = leftEyeDistance / rightEyeDistance, MouthSymmetryRatio = leftMouthDistance / rightMouthDistance, IsSymmetric = Math.Abs(leftEyeDistance - rightEyeDistance) < 5.0 }; } public class FaceSymmetryMetrics { public double EyeSymmetryRatio { get; set; } public double MouthSymmetryRatio { get; set; } public bool IsSymmetric { get; set; } } Part 6: Head Pose Estimation 6.1 Understanding Head Pose Angles Azure Face API provides three Euler angles for head orientation: 6.2 Accessing Head Pose Data public void AnalyzeHeadPose(FaceDetectionResult face) { var headPose = face.FaceAttributes?.HeadPose; if (headPose == null) { _logger.LogWarning("Head pose not available"); return; } double yaw = headPose.Yaw; double pitch = headPose.Pitch; double roll = headPose.Roll; Console.WriteLine("Head Pose:"); Console.WriteLine($" Yaw: {yaw:F2}° (Left/Right)"); Console.WriteLine($" Pitch: {pitch:F2}° (Up/Down)"); Console.WriteLine($" Roll: {roll:F2}° (Tilt)"); InterpretHeadPose(yaw, pitch, roll); } 6.3 Interpreting Head Pose public string InterpretHeadPose(double yaw, double pitch, double roll) { var directions = new List<string>(); // Interpret Yaw (horizontal) if (Math.Abs(yaw) < 10) directions.Add("Looking Forward"); else if (yaw < -20) directions.Add($"Turned Left ({Math.Abs(yaw):F0}°)"); else if (yaw > 20) directions.Add($"Turned Right ({yaw:F0}°)"); // Interpret Pitch (vertical) if (Math.Abs(pitch) < 10) directions.Add("Level"); else if (pitch < -15) directions.Add($"Looking Down ({Math.Abs(pitch):F0}°)"); else if (pitch > 15) directions.Add($"Looking Up ({pitch:F0}°)"); // Interpret Roll (tilt) if (Math.Abs(roll) > 15) { string side = roll < 0 ? "Left" : "Right"; directions.Add($"Tilted {side} ({Math.Abs(roll):F0}°)"); } return string.Join(", ", directions); } 6.4 Visualizing Head Pose on Frame /// <summary> /// Draws head pose information with color-coded indicators. /// </summary> public void DrawHeadPoseInfo(Mat frame, HeadPose headPose, FaceRectangle faceRect) { double yaw = headPose.Yaw; double pitch = headPose.Pitch; double roll = headPose.Roll; int centerX = faceRect.Left + faceRect.Width / 2; int centerY = faceRect.Top + faceRect.Height / 2; string poseText = $"Yaw: {yaw:F1}° Pitch: {pitch:F1}° Roll: {roll:F1}°"; Cv2.PutText(frame, poseText, new Point(faceRect.Left, faceRect.Top - 10), HersheyFonts.HersheySimplex, 0.5, new Scalar(255, 255, 255), 1); int arrowLength = 50; double yawRadians = yaw * Math.PI / 180.0; int arrowEndX = centerX + (int)(arrowLength * Math.Sin(yawRadians)); Cv2.ArrowedLine(frame, new Point(centerX, centerY), new Point(arrowEndX, centerY), new Scalar(0, 255, 0), 2, tipLength: 0.3); double pitchRadians = -pitch * Math.PI / 180.0; int arrowPitchEndY = centerY + (int)(arrowLength * Math.Sin(pitchRadians)); Cv2.ArrowedLine(frame, new Point(centerX, centerY), new Point(centerX, arrowPitchEndY), new Scalar(255, 0, 0), 2, tipLength: 0.3); } 6.5 Detecting Head Orientation States public enum HeadOrientation { Forward, Left, Right, Up, Down, TiltedLeft, TiltedRight, UpLeft, UpRight, DownLeft, DownRight } public List<HeadOrientation> DetectHeadOrientation(HeadPose headPose) { const double THRESHOLD = 15.0; bool lookingUp = headPose.Pitch > THRESHOLD; bool lookingDown = headPose.Pitch < -THRESHOLD; bool lookingLeft = headPose.Yaw < -THRESHOLD; bool lookingRight = headPose.Yaw > THRESHOLD; var orientations = new List<HeadOrientation>(); if (!lookingUp && !lookingDown && !lookingLeft && !lookingRight) orientations.Add(HeadOrientation.Forward); if (lookingUp && !lookingLeft && !lookingRight) orientations.Add(HeadOrientation.Up); if (lookingDown && !lookingLeft && !lookingRight) orientations.Add(HeadOrientation.Down); if (lookingLeft && !lookingUp && !lookingDown) orientations.Add(HeadOrientation.Left); if (lookingRight && !lookingUp && !lookingDown) orientations.Add(HeadOrientation.Right); if (lookingUp && lookingLeft) orientations.Add(HeadOrientation.UpLeft); if (lookingUp && lookingRight) orientations.Add(HeadOrientation.UpRight); if (lookingDown && lookingLeft) orientations.Add(HeadOrientation.DownLeft); if (lookingDown && lookingRight) orientations.Add(HeadOrientation.DownRight); return orientations; } Part 7: Real-Time Video Processing 7.1 Setting Up Video Capture using OpenCvSharp; public class RealTimeFaceAnalyzer : IDisposable { private VideoCapture? _capture; private Mat? _frame; private readonly FaceClient _faceClient; private bool _isRunning; public async Task StartAsync() { _capture = new VideoCapture(0); _frame = new Mat(); _isRunning = true; await Task.Run(() => ProcessVideoLoop()); } private async Task ProcessVideoLoop() { while (_isRunning) { if (_capture == null || !_capture.IsOpened()) break; _capture.Read(_frame); if (_frame == null || _frame.Empty()) { await Task.Delay(1); // Minimal delay to prevent CPU spiking continue; } Cv2.Resize(_frame, _frame, new Size(640, 480)); // Ensure we don't await indefinitely in the rendering loop _ = ProcessFrameAsync(_frame.Clone()); Cv2.ImShow("Face Analysis", _frame); if (Cv2.WaitKey(30) == 'q') break; } Dispose(); } private async Task ProcessFrameAsync(Mat frame) { // This is where your DrawFaceBox, DrawAllLandmarks, and EAR logic will sit. // Remember to use try-catch here to prevent API errors from crashing the loop. } public void Dispose() { _isRunning = false; _capture?.Dispose(); _frame?.Dispose(); Cv2.DestroyAllWindows(); } } 7.2 Optimizing API Calls Problem: Calling Azure Face API on every frame (30 fps) is expensive and slow. Solution: Call API once per second, cache results for 30 frames. private List<FaceDetectionResult> _cachedFaces = new(); private DateTime _lastDetectionTime = DateTime.MinValue; private readonly object _cacheLock = new(); private async Task ProcessFrameAsync(Mat frame) { if ((DateTime.Now - _lastDetectionTime).TotalSeconds >= 1.0) { _lastDetectionTime = DateTime.Now; byte[] imageBytes; Cv2.ImEncode(".jpg", frame, out imageBytes); var faces = await DetectFacesAsync(imageBytes); lock (_cacheLock) { _cachedFaces = faces; } } List<FaceDetectionResult> facesToProcess; lock (_cacheLock) { facesToProcess = _cachedFaces.ToList(); } foreach (var face in facesToProcess) { DrawFaceAnnotations(face, frame); } } Performance Improvement: 30x fewer API calls (1/sec instead of 30/sec) ~$0.02/hour instead of ~$0.60/hour Smooth 30 fps rendering < 100ms latency for visual updates 7.3 Drawing Complete Face Annotations private void DrawFaceAnnotations(FaceDetectionResult face, Mat frame) { DrawFaceBox(face, frame); if (face.FaceLandmarks != null) { DrawAllLandmarks(face.FaceLandmarks, frame); DrawEyeBoxes(face.FaceLandmarks, frame); DrawMouthBox(face.FaceLandmarks, frame); DrawNoseBox(face.FaceLandmarks, frame); double leftEAR = ComputeEAR(face.FaceLandmarks, isLeftEye: true); double rightEAR = ComputeEAR(face.FaceLandmarks, isLeftEye: false); double avgEAR = (leftEAR + rightEAR) / 2.0; Cv2.PutText(frame, $"EAR: {avgEAR:F3}", new Point(10, 30), HersheyFonts.HersheySimplex, 0.6, new Scalar(0, 255, 0), 2); } if (face.FaceAttributes?.HeadPose != null) { DrawHeadPoseInfo(frame, face.FaceAttributes.HeadPose, face.FaceRectangle); string orientation = InterpretHeadPose(face.FaceAttributes.HeadPose.Yaw, face.FaceAttributes.HeadPose.Pitch, face.FaceAttributes.HeadPose.Roll); Cv2.PutText(frame, orientation, new Point(10, 60), HersheyFonts.HersheySimplex, 0.6, new Scalar(255, 255, 0), 2); } } Part 8: Advanced Features and Use Cases 8.1 Face Tracking Across Frames public class FaceTracker { private class TrackedFace { public FaceRectangle Rectangle { get; set; } public DateTime LastSeen { get; set; } public int TrackId { get; set; } } private List<TrackedFace> _trackedFaces = new(); private int _nextTrackId = 1; public int TrackFace(FaceRectangle newFace) { const int MATCH_THRESHOLD = 50; var match = _trackedFaces.FirstOrDefault(tf => { double distance = Math.Sqrt(Math.Pow(tf.Rectangle.Left - newFace.Left, 2) + Math.Pow(tf.Rectangle.Top - newFace.Top, 2)); return distance < MATCH_THRESHOLD; }); if (match != null) { match.Rectangle = newFace; match.LastSeen = DateTime.Now; return match.TrackId; } var newTrack = new TrackedFace { Rectangle = newFace, LastSeen = DateTime.Now, TrackId = _nextTrackId++ }; _trackedFaces.Add(newTrack); return newTrack.TrackId; } public void RemoveOldTracks(TimeSpan maxAge) { _trackedFaces.RemoveAll(tf => DateTime.Now - tf.LastSeen > maxAge); } } 8.2 Multi-Face Detection and Analysis public async Task<FaceAnalysisReport> AnalyzeMultipleFacesAsync(byte[] imageBytes) { var faces = await DetectFacesAsync(imageBytes); var report = new FaceAnalysisReport { TotalFacesDetected = faces.Count, Timestamp = DateTime.Now, Faces = new List<SingleFaceAnalysis>() }; for (int i = 0; i < faces.Count; i++) { var face = faces[i]; var analysis = new SingleFaceAnalysis { FaceIndex = i, FaceLocation = face.FaceRectangle, FaceSize = face.FaceRectangle.Width * face.FaceRectangle.Height }; if (face.FaceLandmarks != null) { analysis.LeftEyeEAR = ComputeEAR(face.FaceLandmarks, true); analysis.RightEyeEAR = ComputeEAR(face.FaceLandmarks, false); analysis.InterPupillaryDistance = CalculateInterEyeDistance(face.FaceLandmarks); } if (face.FaceAttributes?.HeadPose != null) { analysis.HeadYaw = face.FaceAttributes.HeadPose.Yaw; analysis.HeadPitch = face.FaceAttributes.HeadPose.Pitch; analysis.HeadRoll = face.FaceAttributes.HeadPose.Roll; } report.Faces.Add(analysis); } report.Faces = report.Faces.OrderByDescending(f => f.FaceSize).ToList(); return report; } public class FaceAnalysisReport { public int TotalFacesDetected { get; set; } public DateTime Timestamp { get; set; } public List<SingleFaceAnalysis> Faces { get; set; } } public class SingleFaceAnalysis { public int FaceIndex { get; set; } public FaceRectangle FaceLocation { get; set; } public int FaceSize { get; set; } public double LeftEyeEAR { get; set; } public double RightEyeEAR { get; set; } public double InterPupillaryDistance { get; set; } public double HeadYaw { get; set; } public double HeadPitch { get; set; } public double HeadRoll { get; set; } } 8.3 Exporting Landmark Data to JSON using System.Text.Json; public string ExportLandmarksToJson(FaceDetectionResult face) { var landmarks = face.FaceLandmarks; var landmarkData = new { Face = new { Rectangle = new { face.FaceRectangle.Left, face.FaceRectangle.Top, face.FaceRectangle.Width, face.FaceRectangle.Height } }, Eyes = new { Left = new { Outer = new { landmarks.EyeLeftOuter.X, landmarks.EyeLeftOuter.Y }, Inner = new { landmarks.EyeLeftInner.X, landmarks.EyeLeftInner.Y }, Top = new { landmarks.EyeLeftTop.X, landmarks.EyeLeftTop.Y }, Bottom = new { landmarks.EyeLeftBottom.X, landmarks.EyeLeftBottom.Y } }, Right = new { Outer = new { landmarks.EyeRightOuter.X, landmarks.EyeRightOuter.Y }, Inner = new { landmarks.EyeRightInner.X, landmarks.EyeRightInner.Y }, Top = new { landmarks.EyeRightTop.X, landmarks.EyeRightTop.Y }, Bottom = new { landmarks.EyeRightBottom.X, landmarks.EyeRightBottom.Y } } }, Mouth = new { UpperLipTop = new { landmarks.UpperLipTop.X, landmarks.UpperLipTop.Y }, UnderLipBottom = new { landmarks.UnderLipBottom.X, landmarks.UnderLipBottom.Y }, Left = new { landmarks.MouthLeft.X, landmarks.MouthLeft.Y }, Right = new { landmarks.MouthRight.X, landmarks.MouthRight.Y } }, Nose = new { Tip = new { landmarks.NoseTip.X, landmarks.NoseTip.Y }, RootLeft = new { landmarks.NoseRootLeft.X, landmarks.NoseRootLeft.Y }, RootRight = new { landmarks.NoseRootRight.X, landmarks.NoseRootRight.Y } }, HeadPose = face.FaceAttributes?.HeadPose != null ? new { face.FaceAttributes.HeadPose.Yaw, face.FaceAttributes.HeadPose.Pitch, face.FaceAttributes.HeadPose.Roll } : null }; return JsonSerializer.Serialize(landmarkData, new JsonSerializerOptions { WriteIndented = true }); } Part 9: Practical Applications 9.1 Gaze Direction Estimation public enum GazeDirection { Center, Left, Right, Up, Down, UpLeft, UpRight, DownLeft, DownRight } public GazeDirection EstimateGazeDirection(HeadPose headPose) { const double THRESHOLD = 15.0; bool lookingUp = headPose.Pitch > THRESHOLD; bool lookingDown = headPose.Pitch < -THRESHOLD; bool lookingLeft = headPose.Yaw < -THRESHOLD; bool lookingRight = headPose.Yaw > THRESHOLD; if (lookingUp && lookingLeft) return GazeDirection.UpLeft; if (lookingUp && lookingRight) return GazeDirection.UpRight; if (lookingDown && lookingLeft) return GazeDirection.DownLeft; if (lookingDown && lookingRight) return GazeDirection.DownRight; if (lookingUp) return GazeDirection.Up; if (lookingDown) return GazeDirection.Down; if (lookingLeft) return GazeDirection.Left; if (lookingRight) return GazeDirection.Right; return GazeDirection.Center; } 9.2 Expression Analysis Using Landmarks public class ExpressionAnalyzer { public bool IsSmiling(FaceLandmarks landmarks) { double mouthCenterY = (landmarks.UpperLipTop.Y + landmarks.UnderLipBottom.Y) / 2; double leftCornerY = landmarks.MouthLeft.Y; double rightCornerY = landmarks.MouthRight.Y; return leftCornerY < mouthCenterY && rightCornerY < mouthCenterY; } public bool IsMouthOpen(FaceLandmarks landmarks, FaceRectangle faceRect) { double mouthHeight = landmarks.UnderLipBottom.Y - landmarks.UpperLipTop.Y; double mouthOpenRatio = mouthHeight / faceRect.Height; return mouthOpenRatio > 0.08; // 8% of face height } public bool AreEyesClosed(FaceLandmarks landmarks) { double leftEAR = ComputeEAR(landmarks, isLeftEye: true); double rightEAR = ComputeEAR(landmarks, isLeftEye: false); double avgEAR = (leftEAR + rightEAR) / 2.0; return avgEAR < 0.18; // Threshold for closed eyes } } 9.3 Face Orientation for AR/VR Applications public class FaceOrientationFor3D { public (Vector3 forward, Vector3 up, Vector3 right) GetFaceOrientation(HeadPose headPose) { double yawRad = headPose.Yaw * Math.PI / 180.0; double pitchRad = headPose.Pitch * Math.PI / 180.0; double rollRad = headPose.Roll * Math.PI / 180.0; var forward = new Vector3((float)(Math.Sin(yawRad) * Math.Cos(pitchRad)), (float)(-Math.Sin(pitchRad)), (float)(Math.Cos(yawRad) * Math.Cos(pitchRad))); var up = new Vector3((float)(Math.Sin(yawRad) * Math.Sin(pitchRad) * Math.Cos(rollRad) - Math.Cos(yawRad) * Math.Sin(rollRad)), (float)(Math.Cos(pitchRad) * Math.Cos(rollRad)), (float)(Math.Cos(yawRad) * Math.Sin(pitchRad) * Math.Cos(rollRad) + Math.Sin(yawRad) * Math.Sin(rollRad))); var right = Vector3.Cross(up, forward); return (forward, up, right); } } public struct Vector3 { public float X, Y, Z; public Vector3(float x, float y, float z) { X = x; Y = y; Z = z; } public static Vector3 Cross(Vector3 a, Vector3 b) => new Vector3(a.Y * b.Z - a.Z * b.Y, a.Z * b.X - a.X * b.Z, a.X * b.Y - a.Y * b.X); } Conclusion This technical guide has explored the capabilities of Azure Face API for facial analysis in C#. We've covered: Key Capabilities Demonstrated Facial Landmark Detection - Accessing 27 precise points on the face Head Pose Estimation - Tracking yaw, pitch, and roll angles Geometric Calculations - Computing EAR, distances, and ratios Visual Annotations - Drawing bounding boxes with OpenCV Real-Time Processing - Optimized video stream analysis Technical Achievements Computer Vision Math: Euclidean distance calculations Eye Aspect Ratio (EAR) formula Mouth aspect ratio measurements Face symmetry analysis OpenCV Integration: Drawing bounding boxes and landmarks Color-coded feature highlighting Real-time annotation overlays Video capture and processing Practical Applications This technology enables: 👁️ Gaze tracking for UI/UX studies 🎮 Head-controlled game interfaces 📸 Auto-focus camera systems 🎭 Expression analysis for feedback 🥽 AR/VR avatar control 📊 Attention analytics for presentations ♿ Accessibility features for disabled users Performance Metrics Detection Accuracy: 95%+ for frontal faces Landmark Precision: ±2-3 pixels Processing Latency: 200-500ms per API call Frame Rate: 30 fps with caching Further Exploration Advanced Topics to Explore: Face Recognition - Identify individuals Age/Gender Detection - Demographic analysis Emotion Detection - Facial expression classification Face Verification - 1:1 identity confirmation Similar Face Search - 1:N face matching Face Grouping - Cluster similar faces Call to Action 📌 Explore these resources to get started: Official Documentation Azure Face API Documentation Face API REST Reference Azure Face SDK for .NET Related Libraries OpenCVSharp - OpenCV wrapper for .NET System.Drawing - .NET image processing Source Code GitHub Repository: ravimodi_microsoft/SmartDriver Sample Code: Included in this article
Unified Catalog Self-Serve Analytics - Data products and other elements do not sync
Dears, I intend to create a custom interface through a PowerBI report in Fabric to distribute Purview Unified Catalog browser. I use the feature "Unified Catalog Self-Serve Analytics" to deliver the Unified Data Catalog content in a Fabric Lakehouse. However, from the 44 data products created, only 22 are delivered to the lakehouse, in the data product table I have tried in different lakehouse, same result. I would love some advice to help me configure this properly. Do you face the same issue ? Best, AntoineAccess to subAddress Property of Hyperlinks in Powerpoint Javascript API
Recently my company has me developing a Taskpane Add-in for Powerpoint using the Javascript API. Right now the API is still missing a 'subAddress' property for the Powerpoint.Hyperlink class. My heart's deepest longing is to add a slide to a presentation with existing slide-to-slide hyperlinks, check those hyperlinks for discrepancies between the slide ID and the text (ie: a Hyperlink reading '13' that now links to slide 14), and finally correct the text to the subaddress ID of the hyperlink in Javascript. It is my burning passion to do this for every hyperlink in my presentation with the push of a button. In the interest of all mankind I would ask that the 'subAddress' property of the hyperlinks be available for use in addition to the 'address' and 'screenTip' properties which now exist. To the microsoft dev who can grant me this boon I offer half my kingdom. Truly there is no dev more favoured than thee.
Access Northwind Dev Ed - Error GetRandomPkValue
Just downloaded the newest MS Access and selected a new Northwind Dev Ed as the first DB to create. It fails to open due to an error in the code as it searched for a non existing function GetRandomPkValue... The purpose of the missing function is to return a random primary key value by passing in the variables for a query name and a field name and then it should return a "random" numerical ID from those possible based upon the passed in variables... My question is, Is the new Northwind Dev designed to fail on purpose or did I manage to download a corrupted incomplete version or???
Microsoft Project Service Core Jan 2026 Update locked Plans table
We recently noted the Microsoft Project Service Core was updated to 1.0.161.1772: This update has locked our Plans table, no changes are allowed to the forms and creating new columns is greyed out: We cannot make use of Planner in our model driven app (Planner Premium, non-default environment). After a new Plan is created, the user receives this message when opening the Plan: Two days ago we were in this version 1.0.160.2874): and everything was working as expected. Any guidance would be much appreciated as we are not sure if this is a permanent lock or once the update cycle is completed we will be able to go back to edit Plan forms and columns. Thank you in advanceAnnouncing the 2026 Microsoft 365 Community Conference Keynotes
The Microsoft 365 Community Conference returns to Orlando this April, bringing together thousands of builders, innovators, creators, communicators, admins, architects, MVPs, and product makers for three unforgettable days of learning and community. This year’s theme, “A Beacon for Builders, Innovators & Icons of Intelligent Work,” celebrates the people shaping the AI‑powered future — and the keynote lineup reflects exactly that. These leaders will set the tone for our biggest, boldest M365 Community Conference. Below is your first look at the official 2026 keynote order and what to expect from each session. Opening Keynote Jeff Teper — President, Microsoft 365 Collaborative Apps & Platforms Building for the future: Microsoft 365, Agents and AI, what's new and what's next Join Jeff Teper, to discover how AI-powered innovation across Copilot, Teams, and SharePoint is reshaping how people communicate, create, and work together. This session highlights what’s new, what’s fundamentally different, and why thoughtful design continues to matter. See the latest advances in AI and agents, gain insight into where collaboration is headed, and learn why Microsoft is the company to continue to bet on when it comes to building what’s next. Expect: New breakthroughs in collaboration powered by AI and agents Fresh innovations across Teams, Copilot, and SharePoint Practical guidance on how design continues to shape effective teamwork Real world demos that show how AI is transforming communication and content Insight into what is new, what is changing, and what is coming next Business Apps & Agents Keynote Charles Lamanna — President, Business Apps & Agents In this keynote, Charles Lamanna will share how Microsoft 365 Copilot, Copilot Studio, Power Apps, and Agent 365 come together to help makers build powerful agents and help IT teams deploy and govern them at scale. We’ll share how organizations can design, extend, and govern a new model for the intelligent workplace – connecting data, workflows, and systems into intelligent agents that move work forward. Copilot, apps, and agents: the next platform shift for Microsoft 365 Microsoft 365 Copilot has changed how we interact with software. Now AI agents are changing how work gets done – moving from responding to prompts to taking action, across the tools and data your organization already relies on. Expect: A clear explanation of how to leverage and build with Copilot and agents How agents access data, use tools, and complete multi-step work A deeper look at the latest capabilities across Microsoft 365 Copilot, Copilot Studio, and Power Apps End-to-end demos of agents in action Security, Trust & Responsible AI Keynote Vasu Jakkal — Corporate Vice President, Microsoft Security & Rohan Kumar — Corporate Vice President, Microsoft Security, Purview & Trust In our third keynote, Vasu Jakkal and Rohan Kumar join forces to address one of the most urgent topics of the AI era: trust and security at scale. As organizations accelerate into AI‑powered work, safeguarding identities, data, compliance, and governance is mission‑critical. Securing AI: Building Trust in the Era of AI Join Vasu Jakkal and Rohan Kumar as they unveil Microsoft’s vision for securing the new frontier of AI—showing how frontier firms are protecting their data, identities, and models amid rapid AI adoption. This session highlights how Microsoft is embedding security and governance into every layer of our AI platforms and unifying Purview, Defender, Entra, and Security Copilot to defend against threats like prompt injection, model tampering, and shadow AI. You’ll see how built-in protections across Microsoft 365 enable responsible, compliant AI innovation, and gain practical guidance to strengthen your own security posture as AI transforms the way everyone works. Expect: Microsoft's unified approach to secure AI transformation Forward‑looking insights across Security, Purview & Trust Guidance for building safe, responsible AI environments How to protect innovation without slowing momentum Future of Work Fireside Keynote Dr. Jaime Teevan — Chief Scientist & Technical Fellow, Microsoft Dr. Jaime Teevan, one of the foremost thought leaders on AI, productivity, and how work is evolving. In this intimate fireside‑style session, she’ll share research, real‑world insights, and Microsoft’s learnings from being both the maker and the first customer of the AI‑powered workplace. Expect: Insights from decades of workplace research The human side of AI transformation Practical guidance for leaders, creators, and practitioners Why collaboration is essential to unlock the true potential of AI. Community Closer Keynote Karuana Gatimu - Director, Microsoft Customer Advocacy Group & Heather Cook - Principal PM, MIcrosoft Customer Advocacy Group From Momentum to Movement: Where Community Goes Next As the final moments of Microsoft 365 Community Conference come to a close, Heather Cook and Karuana Gatimu invite the community to pause, reflect, and look forward together. This Community Closer keynote connects the breakthroughs, conversations, and shared experiences of the week into a bigger story—one about people, purpose, and progress. Together, they’ll explore how community transforms technology into impact, how advocates and builders shape what’s next across Microsoft 365, and why this moment matters more than ever. More than a recap, this session is a call to action—challenging attendees to take the energy of the conference back to their teams, regions, and communities, and turn inspiration into sustained momentum. You’ll leave not just with ideas, but with clarity, confidence, and a renewed sense of belonging—because community doesn’t end when the conference does. It’s where the real work begins. More Than Keynotes: Why You’ll Want to Be in Orlando The M365 Community Conference brings together: 200+ sessions and breakouts 21 hands‑on workshops 200+ Microsoft engineers and product leaders onsite The Microsoft Innovation Hub Ask the Experts, Meet & Greets, and Community Studio Women in Tech & Allies Luncheon SharePoint’s 25th Anniversary Celebration And an epic attendee party at Universal’s Islands of Adventure Whether you create, deploy, secure, govern, design, or lead with Microsoft 365 — this is your community, and this is your moment. Join Us for the Microsoft 365 Community Conference April 21–23, 2026 Loews Sapphire Falls & Loews Royal Pacific 👉 Register now: https://aka.ms/M365Con26 Use the SAVE150 code for $150USD off current pricing Come be part of the global community building the future of intelligent work.What to Expect from the Copilot & AI Sessions at Microsoft 365 Community Conference
AI isn’t a side conversation at the Microsoft 365 Community Conference—it’s at the center of how work is changing. The Copilot, Agents, & Copilot Services Sessions are designed for anyone who wants to move beyond curiosity and into real-world application. This is an opportunity to learn how Copilot works today and how agents extend it. You will also explore how organizations can govern, scale, and operationalize AI across Microsoft 365. Questions these sessions will help answer: How do we move from experimentation to real value? How do we scale AI responsibly? How do agents fit into the way we already work? What skills do teams need next? Business leaders, IT pros, developers, and community practitioners will join sessions to find practical insights into how AI shows up in your daily work, and what it takes to deploy it responsibly and effectively. There will also be a focus on change management, champion programs, and adoption frameworks, because deploying AI isn’t just a technical decision, it’s a cultural one. From Copilot to Agents: The Shift from Assistance to Action One of the biggest themes across the sessions are the evolution from AI as a helper to AI as an active participant in work. If you’re curious about what “agentic AI” actually means in practice, attending these sessions will make it concrete. Join your peers as you learn how Microsoft 365 Copilot is being extended through agents that reason, act, and automate. Learn about agent orchestration across tools like Copilot Studio, SharePoint, Teams, Planner, and Power Platform. Discover new agent patterns including declarative agents, multi-agent configurations, workflows agents, and computer-use agents. In these sessions you’ll explore how agents can: Take action on your behalf and do more than suggest content. Work across apps, data sources, and workflows. Participate alongside humans as part of the team. Real Adoption Stories (Not Just Demos)! Go beyond feature walkthroughs to focus on how organizations are actually adopting Copilot and agents at scale. In these adoption stories you’ll hear: How Microsoft uses Copilot and agents internally as Customer Zero. What adoption looks like across large enterprises, frontline environments, and regulated industries. Lessons learned from early adopters—what worked, what didn’t, and what they’d do differently. Governance, Trust, and Control Are Front and Center AI adoption only works when people trust it—and trust is built through strong governance. Learn how organizations are balancing innovation with oversight and enabling teams to build and use agents while maintaining enterprise-grade guardrails. A significant portion of the Copilot & AI track is dedicated to: Agent lifecycle management. Security, compliance, and data protection. Preventing oversharing and managing risk. Observability and control using tools like Agent 365, Microsoft Purview, and Copilot Control System. This is especially valuable for IT and security leaders who are being asked to “move fast” without compromising standards. Building with Copilot: No-Code, Low-Code, and Pro-Code Paths No matter where you sit on the technical spectrum, there’s a clear path to learning how to build responsibly and effectively. Not everyone builds the same way and organizations need prompt engineering that delivers results. In these sessions you’ll learn how to choose the right agent type for the job, extending Copilot with enterprise data, and designing agents that are production ready—not just impressive in demos. These sessions are tailored to: Business users and makers getting started with Copilot Studio Low-code developers extending Copilot with workflows, connectors, and prompts Pro developers building advanced agents using APIs, MCP servers, Microsoft Graph, SharePoint Embedded, and Azure AI Copilot in the Flow of Everyday Work Rather than abstract AI concepts, you’ll see end-to-end workflows that demonstrate how Copilot helps people save time, reduce manual work, and focus on higher-value outcomes. The emphasis in these sessions is on practical impact, not hype showing how AI is grounded in real work. These sessions will showcase Copilot and agents embedded into: Meetings, chats, and channels. Task and project management. Content creation and knowledge management. Business processes and frontline operations. Why the Copilot and AI track matters If AI is part of your roadmap, or already part of your day, this track will show you how strategy can meet execution. Join us to explore clear mental models for Copilots and agents, see real examples you can apply to your work, and gain a better understanding of what’s now—and what’s coming next. Each year, #M365Con26 is built around one simple idea: bringing our global community together to learn, grow, innovate, and get hands-on with the technologies shaping the next era of work. This year’s conference delivers our most expansive program yet, including: 200+ sessions, workshops, and AMAs, covering Microsoft 365 Copilot, Teams, SharePoint, OneDrive, Copilot Studio, and more. 100+ Microsoft-led sessions, giving you unprecedented access to the people building the apps and AI capabilities you use every day. A keynote lineup featuring Microsoft leaders including Jeff Teper, Charles Lamanna, Vasu Jakkal, Rohan Kumar, Jaime Teevan, and many more. Deep-dive workshops to elevate your skills with real-world scenarios and hands-on learning. Exclusive attendee parties and networking events where you can connect with peers and icons. You’ll also get the chance to meet hundreds of Microsoft executives, engineers, and product leaders—ask questions, share feedback, and help shape the roadmap of the technologies you rely on. Register now, save $150 with code SAVE150 - https://aka.ms/M365ConRegister
