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對於OCR引擎,我需要使用CCITT4壓縮爲TIFF文件提供OCR引擎。 我們的掃描儀輸出JPEG壓縮的TIFF文件。我想用C#轉換這些文件,使用System.Drawing.Imaging。C#將TIFF JPEG壓縮轉換爲TIFF CompressionCCITT4給出了很多噪音
這會導致噪音很大的圖像。我怎樣才能減少噪音?
我的代碼:
List<byte[]> fRet = new List<byte[]>();
ImageCodecInfo fImageCodecInfo = GetEncoderInfo("image/tiff");
EncoderParameters fEncoderParameters = new EncoderParameters(3);
fEncoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Compression, (long)EncoderValue.CompressionCCITT4);
fEncoderParameters.Param[1] = new EncoderParameter(System.Drawing.Imaging.Encoder.ScanMethod, (int)EncoderValue.ScanMethodNonInterlaced);
fEncoderParameters.Param[2] = new EncoderParameter(System.Drawing.Imaging.Encoder.RenderMethod, (int)EncoderValue.RenderNonProgressive);
//
Image fOrgTiff = Image.FromStream(pInputTiff);
Guid objGuid = fOrgTiff.FrameDimensionsList[0];
FrameDimension objDimension = new FrameDimension(objGuid);
int frameCount = fOrgTiff.GetFrameCount(objDimension);
for (int i = 0; i < frameCount; i++)
{
MemoryStream ms = new MemoryStream();
fOrgTiff.SelectActiveFrame(objDimension, i);
fOrgTiff.Save(ms, fImageCodecInfo, fEncoderParameters);
ms.Position = 0;
fRet.Add(ms.GetBuffer());
}
return fRet;
原始JPEG是否有噪聲或是由轉換引入的噪聲?一個簡單的中值濾波器可能會做得很好。 – 2011-03-03 16:02:09