lossless compression of still images - recommendations?

Robert Heller heller at deepsoft.com
Mon Feb 20 13:05:30 UTC 2017


At Mon, 20 Feb 2017 19:14:36 +0900 "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> On Mon, Feb 20, 2017 at 7:14 AM, Robert Heller <heller at deepsoft.com> wrote:
> > At Sun, 19 Feb 2017 18:40:49 +0000 (UTC) "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:
> >
> >>
> >> On Sun, 19 Feb 2017 13:26:48 -0500 (EST), Robert Heller wrote:
> >> >
> >>
> >> > If the OP wants truely lossless compression, he is not going to be
> >> > using JPEG.  JPEG is *lossy* compression.  He should be using PNG
> >> > instead.
> >>
> >> Of course, you are correct.  I meant to go back and edit that --- then
> >> forgot.
> >>
> >> But, my comment remains:  No two, seperately taken, identical images
> >> should result in an identical bit stream, or large sub-sets of the bit
> >> stream.  But, perhaps, this is the second time I've ever been wrong.  :-)
> >
> > It might depend on the equipment taking the picture and the nature of the
> > scene. If it is an *artifical* scene with very carefully controlled lighting,
> > etc. it might be possible. But yes, with almost any natrual scene with natrual
> > lighting, it is likely impossible for there to be any possibility of near
> > identical scenes to have anything like even remotely similar bit streams.
> >
> > What the OP might be able to do is do some sort of image processing and use
> > some sort of statistical analysis to extract the "near-identical" parts of the
> > images and remove them (or replace them with some sort of "not interesting"
> > mask).  Basically a pre-processing step to cause the *saved* data set to only
> > have the "small" parts where something interesting is happening and tossing
> > the larger parts that are logically "unchanging" (and thus uninteresting).
> 
> In other words, do part of what jpeg compression does, by hand.
> 
> It won't be lossless, of course.
> 
> On the other hand, it might be possible to tune the loss in acceptable
> ways. Manual lossy compression. Interesting thought.

The OP taking pictures of a scene that is *mostly* not changing -- I guessing 
this is a something like a trail camera, where the background is esentually 
not changing, but now and then some wildlife comes through and the OP is only 
interested getting pictures in this elusive wildlife.  I am not suggesting 
manual processing of the images, but some sort of automated process that 
functions at a much higher level than what happens with jpeg.

> 
> >>
> >> Jonesy
> >>
> >>
> >
> > --
> > Robert Heller             -- 978-544-6933
> > Deepwoods Software        -- Custom Software Services
> > http://www.deepsoft.com/  -- Linux Administration Services
> > heller at deepsoft.com       -- Webhosting Services
> 

-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services
  



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