storeSCU and storeSCP compression

[vcslick]

Hello,

I want to take an uncompressed DICOM image, send it out compressed, and then the receiver decompresses the image.

My question would be is using storeSCU the right way to do this?
and does storeSCP accept receiving the image that way?

If yes, then how?

I am only interested in lossless compression.

Hope this helps.

[Marco Eichelberg]

StoreSCU and StoreSCP will not allow you to compress and decompress "on the fly". On the sender side you can use dcmconv (for zlib), dcmcrle (for RLE) or dcmcjpeg (for JPEG) to create a losslessly compressed version of a DICOM object, and on the received side you can use dcmconv/dcmdrle/dcmdjpeg to decompress again. The tool/algorithm most suited for your application will depend on the type of image used. Also note that storescu and storescp must be run with specific options (--propose-xxx and --prefer-xxx, see documentation) in order to correctly negotiate compressed network transfer.

[vcslick]

Thanks very much. It was really helpful.

Here's another question: Is it possible to lose any kind of data when compressing and then decompressing the DICOM image? I compared the original with the compressed image that was decompressed and the images matched with every single pixel.
I used the dcmcjpeg command to compress the image using the following options:
+e1 --encode-lossless-sv1 encode lossless sv1 (default)
+el --encode-lossless encode lossless

and decompressing with the dcmdjpeg command.
Also keep in mind that medical images are being sent.

This should help.

[Marco Eichelberg]

With DCMTK 3.5.4 (but not previous versions), dcmcjpeg with --encode-lossless-sv1 or --encode-lossless should provide a true lossless compression as long as the default --true-lossless codec is used. That is, unless the software contains a bug somewhere, of course.
Please note, however, that a true lossless compression still means that some DICOM header attributes may be modified as permitted by the DICOM standard.