Image quality is bad when convert PNG to TIFF

Aspose.Imaging Product Family
1

We are using aspose to convert image to TIFF using TiffCCITTFax3 format and receiving a really bad quality.

public async Task<string> ConvertPNGToTIF(string strSourceFile, string strDestFile)
        {
            Aspose.Imaging.FileFormats.Png.PngImage imgpng = null;
            try
            {
                // Convert PNG document
                imgpng = new Aspose.Imaging.FileFormats.Png.PngImage(strSourceFile);
                ImageOptionsBase optionsBase = new TiffOptions(Aspose.Imaging.FileFormats.Tiff.Enums.TiffExpectedFormat.TiffCcittFax3);
                optionsBase.ResolutionSettings = resolutionNonPDF;
                imgpng.Save(strDestFile, optionsBase);
                imgpng.Dispose();
            }
            catch (Exception ex)
            {
                return "Error: Image conversion failed, Reason: " + ex.Message.ToString();
            }

            return "Conversion Successfull";
        }

Could someone please give a suggestion?

2

@cuongthieu92 , we are reviewing your case. You will be answered shortly!

3

@cuongthieu92 ,
Attached input color images are low resolution ones, so output black white (BW) Tiff CCIT image has rough color transitions and edges. You can apply some of techniques below to improve color image to binary conversion:

var inputPath = @"";
var outputPath = inputPath + ".tiff";
using (var image = Image.Load(inputPath) as RasterImage)
{
    //you may apply Sharpen filter
    //image.Filter(image.Bounds, new SharpenFilterOptions(5, 1.5));

    //you can dither image to 1 bit (BW) to make smooth color transitions
    //image.Dither(DitheringMethod.FloydSteinbergDithering, 1);

    //or you can turn image to BW using Binarize method, so no dithering is needed
    image.BinarizeOtsu();

    image.Save(outputPath, new TiffOptions(TiffExpectedFormat.TiffCcittFax3));
}

Hope this helps!

4

Thanks for the help, but none of the solution works in this case. Many fields are not readable after the conversion.

5

@cuongthieu92 , Dithering is the only option to improve readability of low resolution image in case of color to BlackWhite conversion. Try using higher resolution images, so output are also better.
Best regards!