/// <summary>
/// Set Initial Condition
/// </summary>
public void ReadAndDisplayFirstFrame(bool performRectanglesDetection, out NSError error)
{
var videoReader = VideoReader.Create(this.videoAsset);
if (videoReader != null)
{
var firstFrame = videoReader.NextFrame();
if (firstFrame != null)
{
List <TrackedPolyRect> firstFrameRects = null;
if (performRectanglesDetection)
{
// Vision Rectangle Detection
var imageRequestHandler = new VNImageRequestHandler(firstFrame, videoReader.Orientation, new NSMutableDictionary());
var rectangleDetectionRequest = new VNDetectRectanglesRequest(null)
{
MinimumAspectRatio = 0.2f,
MaximumAspectRatio = 1f,
MinimumSize = 0.1f,
MaximumObservations = 10
};
imageRequestHandler.Perform(new VNRequest[] { rectangleDetectionRequest }, out NSError performError);
if (performError != null)
{
error = new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.FirstFrameReadFailed);
return;
}
var rectObservations = rectangleDetectionRequest.GetResults <VNRectangleObservation>();
if (rectObservations != null && rectObservations.Any())
{
this.initialRectObservations = rectObservations.ToList();
var detectedRects = new List <TrackedPolyRect>();
for (var index = 0; index < this.initialRectObservations.Count; index++)
{
var rectangleObservation = this.initialRectObservations[index];
var rectColor = TrackedObjectsPalette.Color(index);
detectedRects.Add(new TrackedPolyRect(rectangleObservation, rectColor));
}
firstFrameRects = detectedRects;
}
}
error = null;
this.Delegate?.DisplayFrame(firstFrame, videoReader.AffineTransform, firstFrameRects);
}
else
{
error = new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.FirstFrameReadFailed);
}
}
else
{
error = new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.ReaderInitializationFailed);
}
}
/// <summary>
/// Perform Requests
/// </summary>
public void PerformTracking(TrackedObjectType type, out NSError error)
{
var videoReader = VideoReader.Create(videoAsset);
if (videoReader != null)
{
if (videoReader.NextFrame() != null)
{
this.cancelRequested = false;
// Create initial observations
var inputObservations = new Dictionary <NSUuid, VNDetectedObjectObservation>();
var trackedObjects = new Dictionary <NSUuid, TrackedPolyRect>();
switch (type)
{
case TrackedObjectType.Object:
foreach (var rect in this.ObjectsToTrack)
{
var inputObservation = VNDetectedObjectObservation.FromBoundingBox(rect.BoundingBox);
inputObservations[inputObservation.Uuid] = inputObservation;
trackedObjects[inputObservation.Uuid] = rect;
}
break;
case TrackedObjectType.Rectangle:
foreach (var rectangleObservation in this.initialRectObservations)
{
inputObservations[rectangleObservation.Uuid] = rectangleObservation;
var rectColor = TrackedObjectsPalette.Color(trackedObjects.Count);
trackedObjects[rectangleObservation.Uuid] = new TrackedPolyRect(rectangleObservation, rectColor);
}
break;
}
var requestHandler = new VNSequenceRequestHandler();
var frames = 1;
var trackingFailedForAtLeastOneObject = false;
CVPixelBuffer frame = null;
while (true)
{
if (this.cancelRequested || (frame = videoReader.NextFrame()) == null)
{
break;
}
this.Delegate?.DisplayFrameCounter(frames);
frames += 1;
var rects = new List <TrackedPolyRect>();
var trackingRequests = new List <VNRequest>();
foreach (var inputObservation in inputObservations)
{
VNTrackingRequest request = null;
switch (type)
{
case TrackedObjectType.Object:
request = new VNTrackObjectRequest(inputObservation.Value);
break;
case TrackedObjectType.Rectangle:
if (inputObservation.Value is VNRectangleObservation rectObservation)
{
request = new VNTrackRectangleRequest(rectObservation);
}
else
{
continue;
}
break;
}
request.TrackingLevel = this.TrackingLevel;
trackingRequests.Add(request);
}
// Perform array of requests
requestHandler.Perform(trackingRequests.ToArray(), frame, videoReader.Orientation, out NSError performError);
trackingFailedForAtLeastOneObject = performError != null;
foreach (var processedRequest in trackingRequests)
{
var results = processedRequest.GetResults <VNObservation>();
if (results == null || !results.Any())
{
continue;
}
if (results.FirstOrDefault() is VNDetectedObjectObservation observation)
{
// Assume threshold = 0.5f
var rectStyle = observation.Confidence > 0.5f ? TrackedPolyRectStyle.Solid : TrackedPolyRectStyle.Dashed;
var knownRect = trackedObjects[observation.Uuid];
switch (type)
{
case TrackedObjectType.Object:
rects.Add(new TrackedPolyRect(observation, knownRect.Color, rectStyle));
break;
case TrackedObjectType.Rectangle:
if (observation is VNRectangleObservation rectObservation)
{
rects.Add(new TrackedPolyRect(rectObservation, knownRect.Color, rectStyle));
}
break;
}
// Initialize inputObservation for the next iteration
inputObservations[observation.Uuid] = observation;
}
}
// Draw results
this.Delegate?.DisplayFrame(frame, videoReader.AffineTransform, rects);
var miliseconds = videoReader.FrameRateInSeconds / 1000;
System.Threading.Thread.Sleep((int)miliseconds);
}
this.Delegate?.DidFinifshTracking();
error = trackingFailedForAtLeastOneObject ? new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.FirstFrameReadFailed)
: null;
}
else
{
error = new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.FirstFrameReadFailed);
}
}
else
{
error = new VisionTrackerProcessorError(VisionTrackerProcessorErrorType.ReaderInitializationFailed);
}
}