Generating image from ASCII or program code

Message-ID:<7efa9ba2-c3d8-4f8e-8503-839fc94c6e66@k13g2000prh.googlegroups.com>
Subject:

Generating image from ASCII or program code.

Date:Wed, 25 Nov 2009 12:23:47 +0100


Hello all . I am newbie in image  processing  , so my question may
sound amateur  or zig zag.
       It is well known to all  that raster image is composed of pixel
and each pixel consist of unique value DN . Is  it possible to recode
the entire  image  , so that each pixel is generated by the argument
such as grayscale , DN   and other parameters . Once it is  done image
can be sampled to store the attribute of the pixel  and subsequent
loops can be run to generate the  image .
         This will save the computer storage  space and speed  up the
display of raster  .
    I hope I have been able to clarify the subject  matter . If not  ,
feel free to  ask . I would welcome any relevant idea .

Message-ID:<29f1f48a-a661-40f5-b3c1-82cd9560c3de@j14g2000yqm.googlegroups.com>
Subject:

Re: Generating image from ASCII or program code.

Date:Sun, 29 Nov 2009 16:29:52 +0100


As best I can userstand, you're trying to describing a method of image
compression where you have a model for describing your image, and then
you just save the model instead of all the individual pixels.  Sure,
there are image models, and image compression schemes.  Lots of them.
Do you have any specific questions?

For the speed question, you'd have to look at the tradeoff between
saving and recalling less data versus the time to decompress it, since
it must be decompressed before display.  For example, if I can save a
10 megapixel photo in 500 kb, can I recall and decompress
(reconstruct) the 10 megapixel image in less time that if I simply
saved all 10 megapixels and recalled them all without having to do
decompression?

Message-ID:<cd2bf9df-b5c3-46e4-8020-25fc10d5b788@d21g2000yqn.googlegroups.com>
Subject:

Re: Generating image from ASCII or program code.

Date:Sat, 5 Dec 2009 10:32:34 +0100



Excellent . You  put laser beam to my point of interest .
Image  compression  as far  I know , is accompained by loss of  image
properties ,
which is undesirable  in performing core image processing operations.
What  can  be  the algorithm that  preserves the original image
content ( radiometric , spectral and spatial aspects ) .

Regards
Chandan

Message-ID:<ac77ea6d-1be5-488a-a66c-a74d3d436c5c@k17g2000yqh.googlegroups.com>
Subject:

Re: Generating image from ASCII or program code.

Date:Sat, 5 Dec 2009 13:12:00 +0100


On Dec 5, 4:32=A0am, Geobird <a1chan...@gmail.com> wrote:
> Excellent . You =A0put laser beam to my point of interest .
> Image =A0compression =A0as far =A0I know , is accompained by loss of =A0i=
mage
> properties ,
> which is undesirable =A0in performing core image processing operations.
> What =A0can =A0be =A0the algorithm that =A0preserves the original image
> content ( radiometric , spectral and spatial aspects ) .
>
> Regards
> Chandan

----------------------------------------------
You can use a lossless compression such as PNG, jpeg2000, etc.

Message-ID:<hfdl9g$jj4$1@infosun2.rus.uni-stuttgart.de>
Subject:

Re: Generating image from ASCII or program code.

Date:Sat, 5 Dec 2009 13:56:24 +0100

Geobird wrote:
> Excellent . You  put laser beam to my point of interest .
> Image  compression  as far  I know , is accompained by loss of  image
> properties ,
> which is undesirable  in performing core image processing operations.

Not necessarily. Neither are all compression formats lossy. JPEG-LS 
isn't, original JPEG has a lossless path (though unknown to many), JPEG 
2000 does have a lossless path. The easiest, fastest and one of the best 
is probably JPEG-LS. Lossless in the sense that it re-creates a 2D array 
of integer values without loss. How that 2D array relates to the 
original image is a second question, of course, and just *obtaining* 
that array from a real-world scene creates loss of some sort.

> What  can  be  the algorithm that  preserves the original image
> content ( radiometric , spectral and spatial aspects ) .

"Radiometric"? That requires you to record more than a matrix of 
grey-levels. Spectral properties are neither preserved because, usually, 
color images are stored as triples representing colors in a suitable 
color space. For that, you would need to use a multi-spectral 
representation, but as frequency is a continous signal (similar to 
space), you do have some loss already when sampling the signal. JPEG 
2000 can compress multi-spectral images, also losslessy.

What do you mean by "spatial aspects"? Again, as soon as you have 
pixels, you sampled the original signal already and created loss by a 
limited spatial resolution, but this is a sensor problem and not a 
compression problem.

So long,
	Thomas