Path: news.mathworks.com!newsfeed-00.mathworks.com!newsfeed2.dallas1.level3.net!news.level3.com!postnews.google.com!news2.google.com!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post02.iad.highwinds-media.com!newsfe09.iad.POSTED!7564ea0f!not-for-mail
From: Walter Roberson <roberson@hushmail.com>
User-Agent: Thunderbird 2.0.0.16 (Windows/20080708)
MIME-Version: 1.0
Newsgroups: comp.soft-sys.matlab
Subject: Re: I need to help?
References: <gb0kj5$ov3$1@fred.mathworks.com> <e7ea5034-2104-4ba0-8820-104944d5d5a3@f36g2000hsa.googlegroups.com> <95fd5329-1f60-4e26-9749-9f14566c5ac3@m45g2000hsb.googlegroups.com> <gb137u$n54$1@fred.mathworks.com> <j7VAk.522$zk7.162@newsfe06.iad> <gb1e8d$3q1$1@fred.mathworks.com>
In-Reply-To: <gb1e8d$3q1$1@fred.mathworks.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 26
Message-ID: <xJnBk.11462$Il.5926@newsfe09.iad>
NNTP-Posting-Host: 24.79.146.116
X-Complaints-To: internet.abuse@sjrb.ca
X-Trace: newsfe09.iad 1221986269 24.79.146.116 (Sun, 21 Sep 2008 08:37:49 UTC)
NNTP-Posting-Date: Sun, 21 Sep 2008 08:37:49 UTC
Date: Sun, 21 Sep 2008 03:38:17 -0500
Xref: news.mathworks.com comp.soft-sys.matlab:491158


ABUTALA wrote:

> decibels =
> 
>    29.4771
 
> What is this number

The number is an arbitrary value calculated by the program for no apparent
reason and accidentally printed out because the line that calculates it
has a missing semi-colon at the end.

> because i want to know (find the quality at different &#8216;strength&#8217; value.
> Plot a graph of the quality of  the stego image and the reconstructed image
>  vs &#8216;strength&#8217;.)
> Can you help to answer this?

I would say that to answer that, you are going to have to choose a precise
definition for "quality", and you are going to have to choose a value
range for "strength". At least the code -mentions- "strength" (in one of
the comments) so you have a fighting chance of figuring out what the
valid range is for "strength". Unfortunately there is no scientific definition
for "quality" when it comes to images built from mathematical arrays.
What is the "quality" associated with an image of a cat? What is the "quality"
associated with an image of a dog? How does the image of the cat differ from
the cat itself?