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UwpYoloModelEvalDrawBoxes.cs
using System;
using System.Collections.Generic;
using Windows.Media;
using Windows.UI.Core;
using Windows.UI.Text;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using UwpAppYolo01.Yolo9000;
namespace UwpAppYolo01
{
public sealed partial class MainPage : Page
{
private TinyYoloV2Model _model;
private IList<YoloBoundingBox> _boxes = new List<YoloBoundingBox>();
private readonly YoloWinMlParser _parser = new YoloWinMlParser();
private readonly SolidColorBrush _lineBrushYellow = new SolidColorBrush(Windows.UI.Colors.Yellow);
private readonly SolidColorBrush _lineBrushGreen = new SolidColorBrush(Windows.UI.Colors.Green);
private readonly SolidColorBrush _fillBrush = new SolidColorBrush(Windows.UI.Colors.Transparent);
private readonly double _lineThickness = 2.0;
public MainPage()
{
InitializeComponent();
}
protected override async void OnNavigatedTo(NavigationEventArgs e)
{
LoadYoloOnnxModel();
await CameraPreview.StartAsync();
CameraPreview.CameraHelper.FrameArrived += CameraHelper_FrameArrived;
}
private async void LoadYoloOnnxModel()
{
var file = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Tiny-YOLOv2.onnx"));
_model = await TinyYoloV2Model.CreateTinyYoloV2Model(file); //,
}
private async void CameraHelper_FrameArrived(object sender, Microsoft.Toolkit.Uwp.Helpers.FrameEventArgs e)
{
if (e?.VideoFrame?.SoftwareBitmap == null) return;
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
{
var input = new TinyYoloV2ModelInput { Image = e.VideoFrame };
var output = await _model.EvaluateAsync(input);
_boxes = _parser.ParseOutputs(output.Grid.ToArray());
DrawOverlays(e.VideoFrame);
});
}
private void DrawOverlays(VideoFrame inputImage)
{
YoloCanvas.Children.Clear();
if (_boxes.Count <= 0) return;
var filteredBoxes = _parser.NonMaxSuppress(_boxes, 5, .5F);
foreach (var box in filteredBoxes)
DrawYoloBoundingBox(box, YoloCanvas);
}
private void DrawYoloBoundingBox(YoloBoundingBox box, Canvas overlayCanvas)
{
var x = (uint)Math.Max(box.X, 0);
var y = (uint)Math.Max(box.Y, 0);
var w = (uint)Math.Min(overlayCanvas.ActualWidth - x, box.Width);
var h = (uint)Math.Min(overlayCanvas.ActualHeight - y, box.Height);
var rectStroke = box.Label == "person" ? _lineBrushGreen : _lineBrushYellow;
var r = new Windows.UI.Xaml.Shapes.Rectangle
{
Tag = box,
Width = w,
Height = h,
Fill = _fillBrush,
Stroke = rectStroke,
StrokeThickness = _lineThickness,
Margin = new Thickness(x, y, 0, 0)
};
var tb = new TextBlock
{
Margin = new Thickness(x + 4, y + 4, 0, 0),
Text = $"{box.Label} ({Math.Round(box.Confidence, 4)})",
FontWeight = FontWeights.Bold,
Width = 126,
Height = 21,
HorizontalTextAlignment = TextAlignment.Center
};
var textBack = new Windows.UI.Xaml.Shapes.Rectangle
{
Width = 134,
Height = 29,
Fill = rectStroke,
Margin = new Thickness(x, y, 0, 0)
};
overlayCanvas.Children.Add(textBack);
overlayCanvas.Children.Add(tb);
overlayCanvas.Children.Add(r);
}
}
}
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