diff --git a/TIASshot/ChartDetection/ChartDetector.cs b/TIASshot/ChartDetection/ChartDetector.cs
index 1b9fafd..eb4f2c1 100644
--- a/TIASshot/ChartDetection/ChartDetector.cs
+++ b/TIASshot/ChartDetection/ChartDetector.cs
@@ -81,31 +81,32 @@
             if (_detectionCount < Config.GetInt("Calib/ChartSetCount")) return null;
 
             // ホモグラフィの計算
-            var matPtsPict = Mat.FromArray(ptsPict);
-            var matPtsModel = Mat.FromArray(ptsModel);
-            var matH = Cv2.FindHomography(matPtsModel, matPtsPict);
-            var imgF = new Mat(1545, 810, MatType.CV_8UC3);
-            Cv2.WarpPerspective(img, imgF, matH, imgF.Size());
+            using (var matPtsPict = Mat.FromArray(ptsPict))
+            using (var matPtsModel = Mat.FromArray(ptsModel))
+            using (var matH = Cv2.FindHomography(matPtsModel, matPtsPict))
+            using (var imgF = new Mat(1545, 810, MatType.CV_8UC3)) {
+                Cv2.WarpPerspective(img, imgF, matH, imgF.Size());
 
-            // チャートマスク作成
-            var chartMasks = new List<Mat>();
-            var roiSize = ptsPict.Count < 8 ? 60 : 80;
-            for (int i = 0; i < 24; i++) {
-                var row = i % 6;
-                var col = i / 6;
-                var x = 581 - col * 144 + (ptsPict.Count < 8 ? 10 : 0);
-                var y = 318 + row * 144 + (ptsPict.Count < 8 ? 10 : 0);
-                var roi = new Rect(x, y, roiSize, roiSize);
-                using (var mask = new Mat(1545, 810, MatType.CV_8U)) {
-                    Cv2.Rectangle(mask, roi, new Scalar(255), Cv2.FILLED);
-                    var maskF = new Mat(img.Size(), MatType.CV_8U);
-                    Cv2.WarpPerspective(mask, maskF, matH, maskF.Size());
-                    chartMasks.Add(maskF);
+                // チャートマスク作成
+                var chartMasks = new List<Mat>();
+                var roiSize = ptsPict.Count < 8 ? 60 : 80;
+                for (int i = 0; i < 24; i++) {
+                    var row = i % 6;
+                    var col = i / 6;
+                    var x = 581 - col * 144 + (ptsPict.Count < 8 ? 10 : 0);
+                    var y = 318 + row * 144 + (ptsPict.Count < 8 ? 10 : 0);
+                    var roi = new Rect(x, y, roiSize, roiSize);
+                    using (var mask = new Mat(1545, 810, MatType.CV_8U)) {
+                        Cv2.Rectangle(mask, roi, new Scalar(255), Cv2.FILLED);
+                        var maskF = new Mat(img.Size(), MatType.CV_8U);
+                        Cv2.WarpPerspective(mask, maskF, matH, maskF.Size());
+                        chartMasks.Add(maskF);
+                    }
                 }
-            }
 
-            _showMessage("舌診チャート検出　校正中");
-            return chartMasks;
+                _showMessage("舌診チャート検出　校正中");
+                return chartMasks;
+            }
         }
     }
 }