diff --git a/src/Forms/VobSubOcr.cs b/src/Forms/VobSubOcr.cs
index b8a28ba98..c87278498 100644
--- a/src/Forms/VobSubOcr.cs
+++ b/src/Forms/VobSubOcr.cs
@@ -1269,6 +1269,8 @@ namespace Nikse.SubtitleEdit.Forms
                 nDvbBmp.CropTransparentSidesAndBottom(2, true);
                 if (checkBoxTransportStreamGetColorAndSplit.Checked)
                     _dvbSubColor = nDvbBmp.GetBrightestColor();
+                if (checkBoxAutoTransparentBackground.Checked)
+                    nDvbBmp.MakeBackgroundTransparent(140); //TODO: Put in UI or settings
                 if (checkBoxTransportStreamGrayscale.Checked)
                     nDvbBmp.GrayScale();
                 dvbBmp.Dispose();                
diff --git a/src/Logic/NikseBitmap.cs b/src/Logic/NikseBitmap.cs
index 0256fecb3..4a85e7c21 100644
--- a/src/Logic/NikseBitmap.cs
+++ b/src/Logic/NikseBitmap.cs
@@ -972,5 +972,23 @@ namespace Nikse.SubtitleEdit.Logic
             }
         }
 
+
+        /// <summary>
+        /// Make pixels with some transparency completely transparent
+        /// </summary>
+        /// <param name="minAlpha">Min alpha value, 0=transparent, 255=fully visible</param>
+        internal void MakeBackgroundTransparent(int minAlpha)
+        {
+            byte[] buffer = new byte[4];
+            buffer[0] = 0; // B
+            buffer[1] = 0; // G
+            buffer[2] = 0; // R
+            buffer[3] = 0; // A
+            for (int i = 0; i < _bitmapData.Length; i += 4)
+            {
+                if (_bitmapData[i + 3] < minAlpha)
+                    Buffer.BlockCopy(buffer, 0, _bitmapData, i, 4);
+            }
+        }
     }
 }