// This method is executed by the ThreadPoolTimer, it performs the evaluation on a copy of the VideoFrame
private async void EvaluateVideoFrame(ThreadPoolTimer timer)
{
// If a lock is being held, or WinML isn't fully initialized, return
if (!semaphore.Wait(0) || !modelBindingComplete)
{
return;
}
try
{
using (evaluatableVideoFrame)
{
// ************ WinML Evaluate Frame ************ //
Debug.WriteLine($"RelativeTime in Seconds: {evaluatableVideoFrame.RelativeTime?.Seconds}");
await model.EvaluateAsync(binding, "TinyYOLO");
// Remove overlapping and low confidence bounding boxes
filteredBoxes = parser.NonMaxSuppress(parser.ParseOutputs(outputArray.ToArray()), 5, .5F);
Debug.WriteLine(filteredBoxes.Count <= 0 ? $"No Valid Bounding Boxes" : $"Valid Bounding Boxes: {filteredBoxes.Count}");
}
}
catch (Exception ex)
{
Debug.WriteLine($"EvaluateFrameException: {ex}");
}
finally
{
semaphore.Release();
}
}
private async Task DrawOverlays(VideoFrame inputImage)
{
OverlayCanvas.Children.Clear();
// Render output
if (boxes.Count > 0)
{
// Remove overalapping and low confidence bounding boxes
var filteredBoxes = parser.NonMaxSuppress(boxes, 5, .5F);
foreach (var box in filteredBoxes)
{
await DrawYoloBoundingBoxAsync(inputImage.SoftwareBitmap, box);
}
}
}
// This method is executed by the ThreadPoolTimer, it performs the evaluation on a copy of the VideoFrame
private async void EvaluateVideoFrame(ThreadPoolTimer timer)
{
if (semaphore == null)
{
return;
}
if (!modelCreated)
{
Debug.WriteLine($"EvaluateVideoFrame Skipped - LearningModel Not Ready.");
return;
}
// If a lock is being held, or WinML isn't fully initialized, return
if (!semaphore.Wait(0))
{
Debug.WriteLine($"EvaluateVideoFrame Skipped - Waiting Semaphore Access");
return;
}
if (session == null)
{
try
{
Debug.WriteLine($"Attempting to create LearningModelSession using DeviceKind: {detectedDeviceKind}");
session = new LearningModelSession(model, new LearningModelDevice(detectedDeviceKind));
Debug.WriteLine($"LearningModelSession successfully created.");
}
catch (Exception ex)
{
Debug.WriteLine($"Error Creating Session: {ex.Message}");
model = null;
return;
}
}
Debug.WriteLine($"*************** Evaluating Video Frame [START] ***************");
try
{
using (videoFrameToProcess)
{
// ************ WinML Evaluate Frame ************ //
Debug.WriteLine($"VideoFrame RelativeTime: {videoFrameToProcess.RelativeTime?.Seconds}s");
// Create a binding object from the session
binding = new LearningModelBinding(session);
// Create an image tensor from a video frame
var image = ImageFeatureValue.CreateFromVideoFrame(videoFrameToProcess);
// The YOLO model's input name is "image" and output name is "grid"
var inputName = "image";
var outputName = "grid";
// Bind the image to the input
binding.Bind(inputName, image);
// Process the frame with the model
var results = await session.EvaluateAsync(binding, $"YoloRun {++runCount}");
Debug.WriteLine($"Evaluation Result Success? {results.Succeeded} ");
if (!results.Succeeded)
{
return;
}
Debug.WriteLine($" **** {results.Outputs.Count} Outputs Available ***** ");
foreach (var output in results.Outputs)
{
Debug.WriteLine($" - {output.Key}");
}
// Retrieve the results of evaluation
var resultTensor = results.Outputs[outputName] as TensorFloat;
Debug.WriteLine($"Result Feature Kind: {resultTensor?.Kind.ToString()} ");
var resultVector = resultTensor?.GetAsVectorView();
// Remove overlapping and low confidence bounding boxes
filteredBoxes = parser.NonMaxSuppress(parser.ParseOutputs(resultVector?.ToArray()), 5, .5F);
Debug.WriteLine(filteredBoxes.Count <= 0 ? $"No Valid Bounding Boxes" : $"Valid Bounding Boxes: {filteredBoxes.Count}");
}
}
catch (Exception ex)
{
Debug.WriteLine($"Error: EvaluateFrameException: {ex}");
}
finally
{
semaphore?.Release();
Debug.WriteLine($"*************** Evaluating Video Frame [END] ***************");
}
}
