Re: Wavelet-compressed HRV data

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺

--- In, "Ian S Deans" <ian@i...> wrote:

Are you saving the HRV images as png or jpg. If jpg what setting
are you using. I have increased the jpg setting to 90, but I am
still getting artefacts, although slight improvement. Most
noticeable as you say as the terminator approaches. I am running
everything on one Athlon 1200 extremely successfully, but am
endeavouring to keep HRV image size to a reasonable level without
too much artefacts/pixellation.

That's a good point, Ian. I have increased the default JPEG save
level from 82 to 86, but I believe that Arne van Belle wants to
update some tests on the save level setting. It will be interesting
to see his new results. To convert the 10-bit data to an 8-bit
display format compromises are required, although I believe that my
default settings of min:51, max:1023 and gamma:140 (i.e. 1.40) are
close to the optimum. Of course, you can play with the settings to
suit your needs. The GMS (GOES-9) images are set (at source) to a
gamma of 2, and look rather washed out to me....

For my own comparison tests, I saved in PNG and not JPEG format.


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