On 11 Apr, 11:44, "cedance" <
[email protected]> wrote:
> >On 11 Apr, 10:57, "cedance" <
[email protected]> wrote:
> >> Hi guys,
>
> >> With a little bit of research on the internet and with the idea you
> guys
> >> gave, I managed to write a simple script in matlab, i would like to
> verify
> >> the integrity of the script here,
>
> >As far as both matlab and 2D filtering goes, this seems
> >to be OK. I don't know the details of your application,
> >so I don't have any opinions as to whether this script
> >does the job what your boss wanted your program to do.
>
> >Check with your boss.
>
> >Remember, while your boss or professor might seem a bit
> >distanced or maybe even appear daunting, he or she *does*
> >have an interest in you and your work. The worst students,
> >as far as I am concerned, are those who just fumble around
> >in the dark without asking questions. No one knows what
> >they are doing, or even what the ought to be doing.
> >If somebody comes up and asks "I checked out the terms
> >you mentioned, but I can't quite make sense of them"
> >they show some initiaive and demonstrate interest for
> >the job. Provided they *did* check out the terms, of
> >course...
>
> >As I said before: You are working with a different
> >application than what is usually discussed here. The
> >terminology *seems* similar, but the terms *might* have
> >vastly different meanings to you, as an optician, and
> >to me as a DSP practitioner. You need to be aware of this,
> >and you need to check with your boss that you really are
> >on the right track before you commit to anything you have
> >learned here, either by submitting a program or a thesis.
>
> >Rune
>
> Hey Rune,
>
> Thanks a lot for stressing this point. I would clarify this with my Boss
> and make sure I am on the right track. Very kind of you for pointing out
> timely again!!
As you said in an eariler post: A "Bessel filter" and
a "Bessel function" are two different things. It took
a while to sort tat out here, a professor might have
seen that confusion before and helped you out. Either
way the prof would get an impression of you and how
you work.
I could tell numerous "war stories" about confusion over
the same terms being used in *slightly* different situations
and in *slightly* different ways (the most recent one,
over stock market data, being batteled out here last week...).
The first time I was made aware of the issue, was when
I took my first course on physical acoustics. The first
part of the course was about sonars, expressing the
wave equation in terms of pressure:
d^2p/dx^2 = -1/c^2 d^2p/dt^2 [1]
The signs may be wrong, but leave that for now. The second
part of the course was about seismics. In seismics,
the wave equation is expressed in terms of *tension*, s:
d^2s/dx^2 = +1/c^2 d^2s/dt^2 [2]
The difference is subtle: Positive pressure tends to
shorten a rod, while positive tension tends to lengthen
it. (BTW, did you note the different signs on the right
hand sides of [1] and [2]?)
One of my classmates worked on a term project involving
some manipulations of the *seismics* wave equation.
He hadn't noted the difference in sign, and struggeled
badly to reach his goals for the project. A couple of
days -- literally -- before hus project deadline, he
found that detail. In 48 hours he duplicated 4 months
worth of work and wrote a totally new report.
He made it, but it is not an effort I would like
to witness again, if I can avoid it.
While the problem was caused by a detail in the wave
equation, it wouldn't have helped the least to ask
an expert on, say, electromagnetic wave propagation
to find the error.
Which it is so crucially important to consult people
who know the scope of the problem, when you search
for solutions.
Rune