TIFF compression not working?

Programming Questions Python API
1

I’m a complete Python and CVB beginner, so please be kind :slight_smile:

I just installed the current version of CVB (13.03.002 [x64]), Python 3.8.8 and the wheels package from the aforementioned CVB package (cvb-1.2-cp35.cp36.cp37.cp38-none-win_amd64.whl) and started playing with TIFF images being read and written.

Now I’m wondering about the size of the files, as the documentation states, that those are always written “using lossless LZW77 compression”. Instead they have the full size of the image as the equal BMP image has. If I save the very same source image using IrfanView or GIMP and saving with LZW compression their size is reduced to less than a third of the original, uncompressed size.

So how do I achieve writing a LZW compressed TIFF file to be written?

2

Hi @h.lenz

:smiley: welcome and don’t worry, people are pretty civilized here…

Sorry, that bit was outdated (and will be corrected soon I guess :wink:). This used to be the case until we noticed a problem in libtiff when saving LZW77 compressed RGB48 images (so R, G and B channel with 16 bits each) - at which point the compression was disabled.

Is the PNG format an option for you? It uses similarly good lossless compression and is capable of accomodating 8 and 16 bit data per channel…

3

Thanks for your reply and the warm welcome :slight_smile:
So if I need to stick to TIFF (and not using PNG as an alternative which I will investigate) I have to save with LZW compression myself as this won’t be coming back as functionality of CVB?

4

I won’t say never, but it’ll not be available short term.