diff --git a/Splitter-UI/Program.cs b/Splitter-UI/Program.cs
index 85d83c7..9764329 100644
--- a/Splitter-UI/Program.cs
+++ b/Splitter-UI/Program.cs
@@ -1,6 +1,7 @@
 using Avalonia;
 using Avalonia.Media;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 
 namespace Splitter_UI;
 
@@ -31,12 +32,28 @@ internal sealed class Program
         services.AddTransient<StatusBarViewModel>();
         services.AddTransient<LogPaneViewModel>();
 
+        // splitter services
+        services.AddSingleton<UltraFaceDetector>();
+        services.AddSingleton<YoloOnnxObjectDetector>();
+        services.AddSingleton( x => new SingleThreadedDetector<UltraFaceDetector>(x.GetRequiredService<UltraFaceDetector>()) );
+        services.AddSingleton( x => new SingleThreadedDetector<YoloOnnxObjectDetector>(x.GetRequiredService<YoloOnnxObjectDetector>()));
+        services.AddSingleton<Func<string, IObjectDetector>>( x => detectorName =>
+        {
+            return detectorName switch
+            {
+                "face" => x.GetRequiredService<SingleThreadedDetector<UltraFaceDetector>>(),
+                "body" => x.GetRequiredService<SingleThreadedDetector<YoloOnnxObjectDetector>>(),
+                _      => new DummyDetector()
+            };
+        });
+        services.AddSingleton<splitter.ILogger, GlobalLogger>();
+
         // Domain services (your pipeline)
-        services.AddTransient<IFileProbeService, FileProbeService>();
-        services.AddTransient<IThumbnailService, ThumbnailService>();
+        services.AddTransient<IFileProbeService,    FileProbeService>();
+        services.AddTransient<IThumbnailService,    ThumbnailService>();
         services.AddSingleton<IAutoDecisionService, AutoDecisionService>();
-        services.AddSingleton<IProcessingService, ProcessingService>();
-        services.AddSingleton<ILogService, LogService>();
+        services.AddSingleton<IProcessingService,   ProcessingService>();
+        services.AddSingleton<ILogService,          LogService>();
 
         services.AddSingleton<IFileJobFactory, FileJobFactory>();
 
diff --git a/Splitter-UI/Services/AvaloniaBitmapExtensions.cs b/Splitter-UI/Services/AvaloniaBitmapExtensions.cs
new file mode 100644
index 0000000..f48e98d
--- /dev/null
+++ b/Splitter-UI/Services/AvaloniaBitmapExtensions.cs
@@ -0,0 +1,43 @@
+using System.Runtime.InteropServices;
+using Avalonia;
+using Avalonia.Media.Imaging;
+using OpenCvSharp;
+
+namespace Splitter_UI.Services;
+
+public static class AvaloniaBitmapExtensions
+{
+    public static Mat ToMatContinuous(this Bitmap bmp)
+    {
+        var w = bmp.PixelSize.Width;
+        var h = bmp.PixelSize.Height;
+        var stride = w * 4;
+        var size = h * stride;
+
+        var buffer = new byte[size];
+        var handle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
+
+        try
+        {
+            bmp.CopyPixels(
+                new PixelRect(0, 0, w, h),
+                handle.AddrOfPinnedObject(),
+                size,
+                stride);
+
+            return Mat.FromPixelData(h, w, MatType.CV_8UC4, buffer);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
+    public static Mat ToMatBgrContinuous(this Bitmap bmp)
+    {
+        using var bgra = bmp.ToMatContinuous();
+        var bgr = new Mat();
+        Cv2.CvtColor(bgra, bgr, ColorConversionCodes.BGRA2BGR);
+        return bgr;
+    }
+}
\ No newline at end of file
diff --git a/Splitter-UI/Services/DummyDetector.cs b/Splitter-UI/Services/DummyDetector.cs
new file mode 100644
index 0000000..14f8285
--- /dev/null
+++ b/Splitter-UI/Services/DummyDetector.cs
@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OpenCvSharp;
+
+namespace Splitter_UI.Services;
+
+internal class DummyDetector : IObjectDetector
+{
+    public List<(Rect box, splitter.Point2f center)> DetectAll(Mat frameCont) => [];
+    public void Dispose() {}
+}
diff --git a/Splitter-UI/Services/GlobalLogger.cs b/Splitter-UI/Services/GlobalLogger.cs
new file mode 100644
index 0000000..531e1b6
--- /dev/null
+++ b/Splitter-UI/Services/GlobalLogger.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Splitter_UI.Services;
+
+internal class GlobalLogger(ILogService _logService) : ILogger
+{
+    public void ClearProgress(int progressLevel) { }
+    public void DrawProgress(string name, int progressLine, double progress, TimeSpan eta, double speed) { }
+    public void Log(string prefix, ConsoleColor color, string msg)
+    {
+        _logService.Write($"[{prefix}] {msg}");
+    }
+}
diff --git a/Splitter-UI/Services/SingleThreadedDetector.cs b/Splitter-UI/Services/SingleThreadedDetector.cs
new file mode 100644
index 0000000..0d5bc65
--- /dev/null
+++ b/Splitter-UI/Services/SingleThreadedDetector.cs
@@ -0,0 +1,23 @@
+using OpenCvSharp;
+
+namespace Splitter_UI.Services;
+
+public class SingleThreadedDetector<T>(IObjectDetector _detector) : IObjectDetector
+    where T : IObjectDetector
+{
+    private Lock _lock = new();
+
+    public List<(Rect box, splitter.Point2f center)> DetectAll(Mat frameCont)
+    {
+        lock (_lock)
+        {
+            return _detector.DetectAll(frameCont);
+        }
+    }
+    
+    public void Dispose()
+    {
+        if ( _detector is IDisposable d )
+            d.Dispose();
+    }
+}
diff --git a/Splitter-UI/ViewModels/JobViewModel.cs b/Splitter-UI/ViewModels/JobViewModel.cs
index 6c37ad7..5b019ea 100644
--- a/Splitter-UI/ViewModels/JobViewModel.cs
+++ b/Splitter-UI/ViewModels/JobViewModel.cs
@@ -35,9 +35,11 @@ public partial class JobViewModel : ObservableObject
     public IRelayCommand StepForwardCommand { get; }
     public IRelayCommand StepBackwardCommand { get; }
 
-    private readonly IThumbnailService _thumbnails;
-    private readonly IFileProbeService _fileProbe;
-    private readonly DispatcherTimer _debounceTimer;
+    private readonly IThumbnailService             _thumbnails;
+    private readonly IFileProbeService             _fileProbe;
+    private readonly DispatcherTimer               _debounceTimer;
+    private readonly Func<string, IObjectDetector> _detectorFactory;
+    private readonly ILogger                       _log;
 
     public string FileName => Path.GetFileName(Job.InputFile);
 
@@ -115,11 +117,13 @@ public partial class JobViewModel : ObservableObject
         }
     }
 
-    public JobViewModel(SingleJob job, IThumbnailService thumbnails, IFileProbeService fileProbe)
+    public JobViewModel(SingleJob job, IThumbnailService thumbnails, IFileProbeService fileProbe, Func<string, IObjectDetector> detectorFactory, ILogger log)
     {
-        Job         = job;
-        _thumbnails = thumbnails;
-        _fileProbe  = fileProbe;
+        Job              = job;
+        _thumbnails      = thumbnails;
+        _fileProbe       = fileProbe;
+        _detectorFactory = detectorFactory;
+        _log             = log;
 
         ParametersList.Add(new ParameterEntry("DropoutToleranceFrames", ""));
         ParametersList.Add(new ParameterEntry("EmaFactor", ""));
@@ -164,11 +168,21 @@ public partial class JobViewModel : ObservableObject
             return;
         try
         {
-            var frame = await _thumbnails.CreateThumbnailAsync(Job.InputFile, Probe, TimeSpan.FromSeconds(PositionSeconds), Probe.Width, Probe.Height, Job.Rotate);
-            Preview = new PreviewData(frame, [], null);
+            var frame    = await _thumbnails.CreateThumbnailAsync(Job.InputFile, Probe, TimeSpan.FromSeconds(PositionSeconds), Probe.Width, Probe.Height, Job.Rotate);
+            if (  frame == null )
+                return;
+
+            Preview      = new PreviewData(frame, [], null);
+
+            var detector = _detectorFactory(Job.Detect ?? "");
+            var detections = detector.DetectAll(frame.ToMatContinuous());
+
+            var boxes = detections.Select(x => new Avalonia.Rect(x.box.X, x.box.Y, x.box.Width, x.box.Height)).ToList();
+            Preview = new PreviewData(frame, boxes, null);
         }
         catch (Exception ex)
         {
+            _log.LogError($"Error creating preview for {FileName}: {ex.Message}");
         }
     }