This is a question about TIFF and compression. I have hundreds of LZW compressed tiff images. I wonder, is it possible to convert those to CCITT T.6? Is there some API? Please help.
LZW compression can be used to compress almost any image. CCITT T.6 can compress only bilevel (black and white) images.
If your images are bilevel ones and they are compressed with LZW compression then you can recompress them using tiffcp utility (comes with LibTiff.Net library, free, source code available).
If your images are full-color ones then you will have to convert them to bilevel first. One of my answers contains sample code for such conversion.
Related
I have PDF compressed with JBIG2. How can I recompress it to JPEG or any other compression algorithms?
I want to use open source solution like Itextsharp/PDFSharp or any other c# .net open source project.
You would need to decompress the image data, convert it from 1 bit per component to 8 bits per component, then apply JPEG compression.
But it's a bit unusual to convert monochrome images to color. This should increase the size actually. JBIG2 is pretty good for many monochrome images, why do you want to use JPEG compression on it?
I was reading about image compression, but found that the encoder for c# is lossy, is there any way to make a lossless function compressor in c#? I could only find the lossy option ( https://learn.microsoft.com/en-us/dotnet/api/system.drawing.imaging.encoderparameters?view=netframework-4.8 )
Please have a look at the Fo-Dicom library at GitHub. It is an open-source library for the use in medical imaging. They have implemented all the lossless JPEG algorithms like Jpeg Lossless, Jpeg-LS and Jpeg2000:
https://github.com/fo-dicom/fo-dicom/tree/4562544b8742c78b7b6dd49f1e47bc7952690ee5
Fo-Dicom in itself uses the Health-Efferent library (also open source), which is written in C++, but C# wrappers are implemented:
https://github.com/Efferent-Health/fo-dicom.Codecs
Use PNG to have lossless image compression in .NET.
Because PNG is by design (and also standardized by W3C and IETF) is lossless.
For more information, visit official documentation on encoding and decoding PNG using .NET:
https://learn.microsoft.com/en-us/dotnet/framework/wpf/graphics-multimedia/how-to-encode-and-decode-a-png-image
And for reference, this is the official PNG standard: https://www.rfc-editor.org/rfc/rfc2083
Update 1:
I added clarification of supported lossless image compression in .NET.
JPEG compression is by design lossy in most cases ("acceptably so") but a lossless standard does exist; you might find that some of the c# snippets on this site get you towards your goal:
https://www.graphicsmill.com/docs/gm/applying-lossless-jpeg-transforms.htm
Can we have a multi-page JPEG image?
I have a TIFF image file with multiple pages, but it's too big and first thing comes to mind is to change it to JPEG format, however in JPEG I can see only first page. Therefore I realized only TIFF format allows multiple images in one file. Is that true?
Now I tried to apply different EncoderParameters to reduce the size of TIFF file but no luck. Has someone worked on this issue before? How did you manage to reduce the size of TIFF image?
Encoder.Quality does not seem to work with TIFF at all.
EncoderValue.CompressionLZW is the best option to reduce the size, but I still want to reduce the size more.
Changing dpi to 50 reduced the size, but that made image too blurry.
Thanks for any help.
JPEG is technically a image compression, the JPEG file type is actually JFIF which does not support multi-frames. TIFF is an image container that does support the JPEG compression algorithm though, so you should be able to save the TIFF file as small as saving each page as a seperate JPEG added up.
Here is a stackoverflow post that goes into more detail on how to achieve this:
Create multipage Tiff with JPEG compression .NET
Is there a class in C# library which does LZW compression on TIFF images. I know there is a compression scheme inviolving LZW being present, but using that doesnt decrease the file size whatsoever. Is there any thing that Im assuming wrong? Please correct me if I am.
Because LZW is loseless compression, you can compress TIFF images or any other kind of data using the same way. In C# you can use the SharpLZW library.
--EDIT (1)--
If you want to produce a TIFF file with embedded LZW compression respecting the TIFF specification look at section 13 of the specification.
--EDIT (2)--
There was a patent but it is now expired.
I'm trying to show TIFF files on a picturebox in C#. My code is here:
pictureBox1.Image = Image.FromFile("someName.tif");
This code is working fine, but some TIFF file isn't displaying on the picturebox (the TIFF file isn't broken). What is wrong?
This TIFF file contains one color image compressed using JPEG 4:4:4.
Although Microsoft functions can handle some sub-types of TIFF, including some JPEG compressed varieties, this particular file uses a flavor of JPEG compression known as "old style". It appears Microsoft functions do not support this flavor.
If you need to load such files in your code, you might have to use a dedicated imaging library.