diff --git a/CoreTests/NpcNameFinder/Test_NpcNameFinder.cs b/CoreTests/NpcNameFinder/Test_NpcNameFinder.cs
index 4d80f79d..0f28ba71 100644
--- a/CoreTests/NpcNameFinder/Test_NpcNameFinder.cs
+++ b/CoreTests/NpcNameFinder/Test_NpcNameFinder.cs
@@ -35,7 +35,6 @@ internal sealed class Test_NpcNameFinder : IDisposable
 
     private readonly IWowScreen screen;
 
-    private readonly Stopwatch stopwatch;
     private readonly StringBuilder stringBuilder;
 
     private readonly NpcNameOverlay? npcNameOverlay;
@@ -49,7 +48,6 @@ public Test_NpcNameFinder(ILogger logger, WowProcess process,
         this.logger = logger;
         this.screen = screen;
 
-        stopwatch = new();
         stringBuilder = new();
 
         INpcResetEvent npcResetEvent = new NpcResetEvent();
diff --git a/SharedLib/NpcFinder/LineSegmentOperation.cs b/SharedLib/NpcFinder/LineSegmentOperation.cs
index 543af6da..45a6dd1d 100644
--- a/SharedLib/NpcFinder/LineSegmentOperation.cs
+++ b/SharedLib/NpcFinder/LineSegmentOperation.cs
@@ -95,8 +95,10 @@ public readonly void Invoke(int y, Span<LineSegment> span)
         if (i == 0)
             return;
 
-        Interlocked.Add(ref counter.count, i);
+        int newCount = Interlocked.Add(ref counter.count, i);
+        if (counter.count + newCount > segments.Length)
+            return;
 
-        span[..i].CopyTo(segments.AsSpan(counter.count, i));
+        span[..i].CopyTo(segments.AsSpan(counter.count, newCount));
     }
 }
diff --git a/SharedLib/NpcFinder/NpcNameFinder.cs b/SharedLib/NpcFinder/NpcNameFinder.cs
index 25d47ad7..0ada638b 100644
--- a/SharedLib/NpcFinder/NpcNameFinder.cs
+++ b/SharedLib/NpcFinder/NpcNameFinder.cs
@@ -338,7 +338,7 @@ public void Update()
         resetEvent.Reset();
 
         ReadOnlySpan<LineSegment> lineSegments =
-            PopulateLines(bitmapProvider, Area, colorMatcher, Area,
+            PopulateLines(colorMatcher, Area,
             ScaleWidth(MinHeight), ScaleWidth(WidthDiff));
 
         Npcs = DetermineNpcs(lineSegments);
@@ -520,11 +520,10 @@ private int YOffset(Rectangle area, Rectangle npc)
 
     [SkipLocalsInit]
     private ReadOnlySpan<LineSegment> PopulateLines(
-        IScreenImageProvider provider, Rectangle rect,
         Func<byte, byte, byte, bool> colorMatcher,
         Rectangle area, float minLength, float lengthDiff)
     {
-        const int RESOLUTION = 32;
+        const int RESOLUTION = 16;
         int rowSize = (area.Right - area.Left) / RESOLUTION;
         int height = (area.Bottom - area.Top) / RESOLUTION;
         int totalSize = rowSize * height;
@@ -553,7 +552,7 @@ private ReadOnlySpan<LineSegment> PopulateLines(
             in operation);
 
         pooler.Return(segments);
-        return new(segments, 0, counter.count);
+        return new(segments, 0, Math.Min(segments.Length, counter.count));
     }
 
     public Point ToScreenCoordinates()