C# Converting TIFF JPEG compression to TIFF CompressionCCITT4 gives a lot of noise -

for ocr engine need feed ocr engine tiff files ccitt4 compression. our scanner outputs tiff files jpeg compression. want convert these files c#, using system.drawing.imaging.

this results in images lot of noise. how can reduce noise?

my code:

        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);         (int = 0; < framecount; i++)         {             memorystream ms = new memorystream();             forgtiff.selectactiveframe(objdimension, i);             forgtiff.save(ms, fimagecodecinfo, fencoderparameters);             ms.position = 0;             fret.add(ms.getbuffer());         }         return fret; 

as brannon said, ccitt4 binary format (black/white) image automatically binarized. documentation says: "the ccitt3, ccitt4, , rle require pixelformat value set blackwhite. setting pixelformat other value resets compression property value default."

you can try reduce noise choosing better binarization threshold. can @ algorithms provided open-source imaging libraries aforge.net or emgucv.