diff --git a/TIASshot/ColorCorrection/ColorCorrector.cs b/TIASshot/ColorCorrection/ColorCorrector.cs
index c253291..eadebea 100644
--- a/TIASshot/ColorCorrection/ColorCorrector.cs
+++ b/TIASshot/ColorCorrection/ColorCorrector.cs
@@ -198,48 +198,21 @@
         /// <param name="conv"></param>
         /// <returns>8bit 画像</returns>
         internal Mat ConvertImage(Mat src, Mat conv) {
-            // 1. 型変換: src を CV_64FC3 に変換（in-place）
             if (src.Type() != MatType.CV_64FC3) {
                 src.ConvertTo(src, MatType.CV_64FC3);
             }
+            using (var flatten = src.Reshape(3, src.Height * src.Width))
+            using (var extended = ExtendMat(flatten, conv.Rows))
+            using (var converted = (extended * conv).ToMat())
+            using (var convertedImage = converted.Reshape(3, src.Height)) {
+                //Clipping to 8bit range
+                //unsafe {
+                //    convertedImage.ForEachAsVec3d(Clip8bit);
+                //}
 
-            // 2. Reshape: メモリ共有を避けるため Clone を使用
-            Mat flatten = null;
-            Mat extended = null;
-            Mat matrixProduct = null;
-            Mat convertedImage = null;
-            Mat convImg8 = null;
-
-            try {
-                // Reshape は元のメモリを共有するため、Clone で独立コピーを作成
-                using (var flattenView = src.Reshape(3, src.Height * src.Width)) {
-                    flatten = flattenView.Clone();
-                }
-
-                // 3. 行列拡張
-                extended = ExtendMat(flatten, conv.Rows);
-
-                // 4. 行列乗算: MatExpr の一時オブジェクトを避けるため、明示的に ToMat + Clone
-                using (var product = (extended * conv).ToMat()) {
-                    matrixProduct = product.Clone();
-                }
-
-                // 5. Reshape: 再び Clone で安全化
-                using (var convertedView = matrixProduct.Reshape(3, src.Height)) {
-                    convertedImage = convertedView.Clone();
-                }
-
-                // 6. 8bit 変換
-                convImg8 = new Mat();
+                var convImg8 = new Mat();
                 convertedImage.ConvertTo(convImg8, MatType.CV_8UC3);
-
                 return convImg8;
-            } finally {
-                // 中間 Mat を確実に破棄（convImg8 は返り値なので破棄しない）
-                flatten?.Dispose();
-                extended?.Dispose();
-                matrixProduct?.Dispose();
-                convertedImage?.Dispose();
             }
         }
 
@@ -251,9 +224,7 @@
         internal Mat ExtendMat(Mat src, int channels) {
             if (src.Cols * src.Channels() != 3) return src;
             var dst = new Mat(src.Rows, channels, MatType.CV_64FC1);
-            // Parallel.For を通常の for ループに変更
-            // Releaseモード最適化 + 低スペックPCでのスレッド競合を回避
-            for (int row = 0; row < src.Rows; row++) {
+            Parallel.For(0, src.Rows, row => {
                 var vals = new double[] {
                     src.Cols == 1 ? src.At<Vec3d>(row, 0)[2] : src.At<double>(row, 2),  // R
                     src.Cols == 1 ? src.At<Vec3d>(row, 0)[1] : src.At<double>(row, 1),  // G
@@ -263,7 +234,7 @@
                 for (int i = 0; i < channels; i++) {
                     dst.At<double>(row, i) = vals[ExtendChannels[i][0]] * vals[ExtendChannels[i][1]] * vals[ExtendChannels[i][2]];
                 }
-            }
+            });
             return dst;
         }
     }