tests started and tuning

tools/OcrDaemon/ImagePreprocessor.cs

@@ -9,17 +9,16 @@ static class ImagePreprocessor
     /// <summary>
     /// Pre-process an image for OCR using morphological white top-hat filtering.
     /// Isolates bright tooltip text, suppresses dim background text visible through overlay.
-    /// Pipeline: grayscale → morphological top-hat → Otsu binary → 2x upscale
+    /// Pipeline: grayscale → morphological top-hat → Otsu binary → upscale
     /// </summary>
-    public static Bitmap PreprocessForOcr(Bitmap src)
+    public static Bitmap PreprocessForOcr(Bitmap src, int kernelSize = 25, int upscale = 2)
     {
         using var mat = BitmapConverter.ToMat(src);
         using var gray = new Mat();
         Cv2.CvtColor(mat, gray, ColorConversionCodes.BGRA2GRAY);
 
         // Morphological white top-hat: isolates bright text on dark background
-        // Kernel size 25x25 captures text strokes, suppresses dim background text
-        using var kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(25, 25));
+        using var kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(kernelSize, kernelSize));
         using var tophat = new Mat();
         Cv2.MorphologyEx(gray, tophat, MorphTypes.TopHat, kernel);
 
@@ -27,11 +26,15 @@ static class ImagePreprocessor
         using var binary = new Mat();
         Cv2.Threshold(tophat, binary, 0, 255, ThresholdTypes.BinaryInv | ThresholdTypes.Otsu);
 
-        // 2x upscale for better LSTM recognition
-        using var upscaled = new Mat();
-        Cv2.Resize(binary, upscaled, new OpenCvSharp.Size(binary.Width * 2, binary.Height * 2),
-            interpolation: InterpolationFlags.Cubic);
+        // Upscale for better LSTM recognition
+        if (upscale > 1)
+        {
+            using var upscaled = new Mat();
+            Cv2.Resize(binary, upscaled, new OpenCvSharp.Size(binary.Width * upscale, binary.Height * upscale),
+                interpolation: InterpolationFlags.Cubic);
+            return BitmapConverter.ToBitmap(upscaled);
+        }
 
-        return BitmapConverter.ToBitmap(upscaled);
+        return BitmapConverter.ToBitmap(binary);
     }
 }