How convert picture to scan form (consider perpective deskew, ..), by opencv

private byte[] AutoRotate(TessBaseAPI api, Bitmap im)
     {



         Image<Gray, byte> image = new Image<Gray, byte>(im);

         Bitmap image1 = image.ToBitmap();
         DocumentSkewChecker skewChecker = new DocumentSkewChecker();
         // get documents skew angle
         double angle = skewChecker.GetSkewAngle(image1);

         RotateBilinear rotationFilter = new RotateBilinear(-angle, false);
         rotationFilter.FillColor = Color.White;
         // rotate image applying the filter
         Bitmap rotatedImage = rotationFilter.Apply(image1);
         rotatedImage.Save("c:\\rotated0.png");


         RotateBilinear rotationFilter1 = new RotateBilinear(-90, false);
         Bitmap rotatedImage1 = rotationFilter1.Apply(rotatedImage);
         rotatedImage1.Save("c:\\rotated1.png");

         RotateBilinear rotationFilter2 = new RotateBilinear(-180, false);
         Bitmap rotatedImage2 = rotationFilter2.Apply(rotatedImage);
         rotatedImage2.Save("c:\\rotated2.png");

         RotateBilinear rotationFilter3 = new RotateBilinear(-270, false);
         Bitmap rotatedImage3 = rotationFilter3.Apply(rotatedImage);
         rotatedImage3.Save("c:\\rotated3.png");




         string first = "";
         string second = "";
         string third = "";
         string fourth = "";

         MemoryStream st = null;
         using (st = new MemoryStream())
         {
             rotatedImage.Save(st, ImageFormat.Png);
             api.SetImage(Pix1.pixReadFromMemoryStream(st));
             api.Recognize();

             first = api.GetUTF8Text();
         }


         st = null;
         using (st = new MemoryStream())
         {
             rotatedImage1.Save(st, ImageFormat.Png);
             api.SetImage(Pix1.pixReadFromMemoryStream(st));
             api.Recognize();

             second = api.GetUTF8Text();
         }

         st = null;
         using (st = new MemoryStream())
         {
             rotatedImage2.Save(st, ImageFormat.Png);
             api.SetImage(Pix1.pixReadFromMemoryStream(st));
             api.Recognize();

             third = api.GetUTF8Text();
         }

         st = null;
         using (st = new MemoryStream())
         {
             rotatedImage3.Save(st, ImageFormat.Png);
             api.SetImage(Pix1.pixReadFromMemoryStream(st));
             api.Recognize();

             fourth = api.GetUTF8Text();
         }

         string[] results = { first, second, third, fourth };
         string result = "";
         int son = 0;
         for (int i = 0; i < results.Length; i++)
         {
             if (results[i].Length > son)
             {
                 son = results[i].Length;
                 if (i == 0)
                 {
                     result = "first";
                 }
                 else if (i == 1)
                 {
                     result = "second";
                 }
                 else if (i == 2)
                 {
                     result = "third";
                 }
                 else
                 {
                     result = "fourth";
                 }

             }

         }
         Bitmap resultim;
         if (result == "first")
         {
             resultim = rotatedImage;
         }

         else if (result == "second")
         {
             resultim = rotatedImage1;
         }

         else if (result == "third")
         {
             resultim = rotatedImage2;
         }
         else
         {
             resultim = rotatedImage3;
         }

         resultim.Save("c:\\imresult.png");
         ImageConverter converter = new ImageConverter();
         return (byte[])converter.ConvertTo(resultim, typeof(byte[]));

     }