Subject: [interferometry] Digest Number 1847[1 Attachment]
From: interferometry@yahoogroups.com
Date: 9/14/2011, 2:02 AM
To: interferometry@yahoogroups.com

interferometry
interferometry

Messages In This Digest (12 Messages)

1a.
Re: PSI software? From: Vladimir
1b.
Re: PSI software? From: Ed
1c.
Re: PSI software? From: vladimir galogaza
1d.
Re: PSI software? From: Michael Peck
1e.
Re: PSI software? From: atmpob
2a.
Re: cube beamsplitter for bath PSI From: Jan
2b.
Re: cube beamsplitter for bath PSI From: julien_vdm
2c.
Re: cube beamsplitter for bath PSI From: julien_vdm
2d.
Re: cube beamsplitter for bath PSI From: vladimir galogaza
2e.
Re: cube beamsplitter for bath PSI From: vladimir galogaza
3.
FP interferometer... Tracking Rings From: aesbrown77
4a.
Okie Tex? From: atmpob
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Messages

1a.

Re: PSI software?

Posted by: "Vladimir" vladimir.galogaza1@zg.t-com.hr   vgalogaza

Tue Sep 13, 2011 2:59 am (PDT)



Hi Ed,

> How useable is the PSI software especially for guys like me who can't program
> their VCR much less computer code?

Michael will certainly answer your questions but perhaps you are interested also
in opinion of one user of Michaels PSI program. Being also not particularly
computer or programming literate, I had some problems, but Michael and Stephen,
experts in the field, were very helpful in coaching me between Scylla and Haribda safely.

> How do you input the numerous igrams

Interferograms are captured either by webcam or digital camera and stored in a computer
as .jpg files.
I presume you know how to do it. Each stored interferogram has its file name, usually given by camera,example:
IMG0012.jpg, IMG0013.jpg ...... etc. Than you put a list of all igram file names into one notepad,
or some other word program file, and store it as for example files 12-16.txt in the same folder as
interferograms. This is done by typing text like writing a post or letters, no programming is involved.
Michaels PSI program requires as input a full path of where interferograms and .txt file are saved
and the name of the text file.
Example Path=C:/Ed PSI/Interferograms
Files= files 12-16.txt
PSI program will read interferogram file names from .txt file, find the interferograms, input them in the
program and analyze. Results of analysis will be printed or displayed in the form of list
of Zernike coefficients, 2D image of waveform errors color coded with numbered contours,
and 3D interactive image of the mirror.
In the beginning you will be perhaps little in doubt what to do but after first attempt it will become
just routine. And you may count on every help you may ask for.

The advantage of Michaels program is that it can be easily tailored to particular needs,
wishes or tastes. This is not so easy with other types of programs which you may find
easier at the beginning but limited afterwards..

Michael has made a demo version of the program which will show you how it all works
on set of interferograms included for demo. Try it.

Regards
Vladimir.
1b.

Re: PSI software?

Posted by: "Ed" opticsed@gmail.com   opticsed

Tue Sep 13, 2011 1:16 pm (PDT)



Vladimir,

A couple more questons:

Are these random igrams; don't you need to know the phase or time relationship of the igrams?

What's the program called and is it in Michael's folder?

I have a Zygo-GH non phase shifting interferometer. The laser tube is non-stabilized and phases a lot until it reaches final temperature. I think I can just turn it off for a minute and shoot igrams during warm up.
Thanks for you help,

Ed

--- In interferometry@yahoogroups.com, "Vladimir" <vladimir.galogaza1@...> wrote:
>
> Hi Ed,
>
> > How useable is the PSI software especially for guys like me who can't program
> > their VCR much less computer code?
>
> Michael will certainly answer your questions but perhaps you are interested also
> in opinion of one user of Michaels PSI program. Being also not particularly
> computer or programming literate, I had some problems, but Michael and Stephen,
> experts in the field, were very helpful in coaching me between Scylla and Haribda safely.
>
> > How do you input the numerous igrams
>
> Interferograms are captured either by webcam or digital camera and stored in a computer
> as .jpg files.
> I presume you know how to do it. Each stored interferogram has its file name, usually given by camera,example:
> IMG0012.jpg, IMG0013.jpg ...... etc. Than you put a list of all igram file names into one notepad,
> or some other word program file, and store it as for example files 12-16.txt in the same folder as
> interferograms. This is done by typing text like writing a post or letters, no programming is involved.
> Michaels PSI program requires as input a full path of where interferograms and .txt file are saved
> and the name of the text file.
> Example Path=C:/Ed PSI/Interferograms
> Files= files 12-16.txt
> PSI program will read interferogram file names from .txt file, find the interferograms, input them in the
> program and analyze. Results of analysis will be printed or displayed in the form of list
> of Zernike coefficients, 2D image of waveform errors color coded with numbered contours,
> and 3D interactive image of the mirror.
> In the beginning you will be perhaps little in doubt what to do but after first attempt it will become
> just routine. And you may count on every help you may ask for.
>
> The advantage of Michaels program is that it can be easily tailored to particular needs,
> wishes or tastes. This is not so easy with other types of programs which you may find
> easier at the beginning but limited afterwards..
>
> Michael has made a demo version of the program which will show you how it all works
> on set of interferograms included for demo. Try it.
>
> Regards
> Vladimir.
>

1c.

Re: PSI software?

Posted by: "vladimir galogaza" vladimir.galogaza1@zg.t-com.hr   vgalogaza

Tue Sep 13, 2011 2:05 pm (PDT)



Ed,

>Are these random igrams; don't you need to know the phase or time relationship of the igrams?

Michael has two programs. One requires known number of equal phase shifts per each full
cycle. Interferograms must be shot so that their size and position within frame is same for each interferogram in one PSI set.

Another program ( PCA based) does not care about knowing the amount of phase shift.
But I am not certain if phases can be random or consecutive. Michael should
tell us.

>What's the program called and is it in Michael's folder?

The windows binary is at < http://wildlife-pix.com/rpackages/zernike_3.0.0.zip>.
Actualy "zernike" is whole bunch of programs (functions) from which a working
program takes what is needed in particular situation. because of this a programs
we use are very compact and we do not care much about what is going on behind
the scene. But every part of the programs is very well documented.
When you will be that far we can go in details.

>I think I can just turn it off for a minute and shoot igrams during warm up.

Michael once did exactly this sort of thing, so it works. If the laser has sufficient amount
of phase drift for analysis, you will have to find out experimentally.

Regards
Vladimir.

1d.

Re: PSI software?

Posted by: "Michael Peck" mpeck1@ix.netcom.com   mikepeck5440

Tue Sep 13, 2011 2:08 pm (PDT)



At 09:05 PM 9/12/2011, opticsed wrote:
> I guess this question is for Michael. How useable is the PSI
> software especially for guys like me who can't program their VCR
> much less computer code? How do you input the numerous
> igrams? Digital cameras can take short movies, would these be useful?
> Have you thought about making it into a saleable product?

Ed:

The software directly supports input from jpeg or tiff files. Any
still camera will output at least jpegs. There is lots of software
out there to convert between graphics formats. For example just
recently a group member posted a short avi video clip that both Dale
and I converted to jpegs, and those were easily batch processed.

As for making something "saleable," who would buy it?

When I started writing software to do PSI analysis I had the idea
that relatively sophisticated users would use it (or software they
wrote themselves for that matter) to do exploratory data analysis,
and if things panned out someone whose first name begins with D would
incorporate it into canned software for production testing. That
could still happen -- the phase computation (using least squares)
isn't that hard, and once you have a phase estimate what you do with
it is the same regardless of the algorithm that generated it.

>I have a Zygo-GH non phase shifting interferometer. The laser tube
>is non-stabilized and phases a lot until it reaches final temperature.

I've looked at batches of data from 3 people who've successfully done
PSI this way (one of them being me). I'd be happy to take a look at
yours if you don't mind sharing it.

Mike P.

------
Michael Peck
mpeck1@ix.netcom.com
http://wildlife-pix.com

1e.

Re: PSI software?

Posted by: "atmpob" atmpob@yahoo.com   atmpob

Tue Sep 13, 2011 7:49 pm (PDT)



"D" never could figure out how to convert the code into C. Even with Steve Koehler's help. We sort of stalled trying to figure out the math behind on of R's functions that Mike uses. Then there didn't seem to be any demand and I also lost interest in PSI since I get what I need from what I already have.

I also have not wanted to fork out the money for the latest Microsoft C++ MFC compiler that I need to continue improving OpenFringe in its current state on the newer windows platforms. It is time to write it in a more portable GUI but I have lost the drive to do so.

I wrote most of it originally when I was unemployed so I had lots of time. Now I'm employed.

"D"

--- In interferometry@yahoogroups.com, Michael Peck <mpeck1@...> wrote:
>
> At 09:05 PM 9/12/2011, opticsed wrote:
.....
>
> As for making something "saleable," who would buy it?
>
> When I started writing software to do PSI analysis I had the idea
> that relatively sophisticated users would use it (or software they
> wrote themselves for that matter) to do exploratory data analysis,
> and if things panned out someone whose first name begins with D would
> incorporate it into canned software for production testing. That
> could still happen -- the phase computation (using least squares)
> isn't that hard, and once you have a phase estimate what you do with
> it is the same regardless of the algorithm that generated it.
>

2a.

Re: cube beamsplitter for bath PSI

Posted by: "Jan" jhm.vangastel@ziggo.nl   janvangastel

Tue Sep 13, 2011 3:12 am (PDT)



It is very difficult to conclude from this discussion what's needed to re-build a normal Bath interferometer into a PSI Bath Interferometer. Will I only need (one) extra - polarizing - beam splitter? Or do I need two 'polarizers' whatever that may be, plus a polarizing beam splitter? Or do I need a 'polarizer' plus one polarizing beam splitter? And if I need a polarizing beam splitter: do I replace the normal one for the polarizing, or is it extra?

Jan
http://members.ziggo.nl/jhm.vangastel/Astronomy/

--- In interferometry@yahoogroups.com, "vladimir galogaza" <vladimir.galogaza1@...> wrote:
>
> Julien,
>
> >bought quarter wave retarder film and polarizer from anchor optics :
>
> You need two polarizers. How many have you got from Anchor optics ?
> Glass types are better than film because it is easier to clean glass without
> damaging the surface.
> For PSI Bath you need only one more item, a polarizing beam splitter cube.
> Do you already know which one will you buy and its price?
>
> Regards
> Vladimir.
>

2b.

Re: cube beamsplitter for bath PSI

Posted by: "julien_vdm" microgrit@yahoo.fr   julien_vdm

Tue Sep 13, 2011 4:13 am (PDT)



Thank you !
In the second link there is also inexpensive quarter waveplate. It's interesting.

And last question : what is the tolerance in the rotation of the polarizer ? I will do it by hand so there will be always a few degrees of error i think.

Julien

--- In interferometry@yahoogroups.com, "vladimir galogaza" <vladimir.galogaza1@...> wrote:
>
> Julien,
>
> >But now the problem is where to find polarizing beam splitter cube
> >at an affordable price... Do you have ideas ?
>
> Apart from not knowing what is "affordable price" for you,
> I will give you address where I have got mine for euro 75.- plus
> euro 10 for shipping. Item code PBSC-1, Polarizing beam splitter cube
> 10 mm, broadband 410-660 nm.
> www.synchrovision.co.uk contact person Martin Pelikan.
>
> I have seen offer for $59 but never checked it.
> http://www.foctek.net/products/optics/P_C_B.htm
>
> Good luck and regards.
> Vladimir.
>

2c.

Re: cube beamsplitter for bath PSI

Posted by: "julien_vdm" microgrit@yahoo.fr   julien_vdm

Tue Sep 13, 2011 4:15 am (PDT)




If i am not mistaking, you need to replace your normal cube by a polarizing one. You also have to add two polarizers and one quarter wave plate.

Julien

--- In interferometry@yahoogroups.com, "Jan" <jhm.vangastel@...> wrote:
>
> It is very difficult to conclude from this discussion what's needed to re-build a normal Bath interferometer into a PSI Bath Interferometer. Will I only need (one) extra - polarizing - beam splitter? Or do I need two 'polarizers' whatever that may be, plus a polarizing beam splitter? Or do I need a 'polarizer' plus one polarizing beam splitter? And if I need a polarizing beam splitter: do I replace the normal one for the polarizing, or is it extra?
>
> Jan
> http://members.ziggo.nl/jhm.vangastel/Astronomy/
>
>
>
> --- In interferometry@yahoogroups.com, "vladimir galogaza" <vladimir.galogaza1@> wrote:
> >
> > Julien,
> >
> > >bought quarter wave retarder film and polarizer from anchor optics :
> >
> > You need two polarizers. How many have you got from Anchor optics ?
> > Glass types are better than film because it is easier to clean glass without
> > damaging the surface.
> > For PSI Bath you need only one more item, a polarizing beam splitter cube.
> > Do you already know which one will you buy and its price?
> >
> > Regards
> > Vladimir.
> >
>

2d.

Re: cube beamsplitter for bath PSI

Posted by: "vladimir galogaza" vladimir.galogaza1@zg.t-com.hr   vgalogaza

Tue Sep 13, 2011 5:38 am (PDT)

[Attachment(s) from vladimir galogaza included below]

Jan,

>It is very difficult to conclude from this discussion what's needed to re-build a normal Bath
> interferometer into a PSI Bath Interferometer.

Attached picture should clarify it. Green colored elements are specific for PSI Bath.
To convert Bath into PSI Bath the beam splitter cube should be removed and replaced with
polarizing beam splitter cube and 3 additional components added, two linear
polarizers and one Quarter Wave Plate (QWP). Flat mirror, lens, laser and camera are the same.
Picture is symbolic. Component locations are not realistic. Diverging lens should
be as close as possible to the cube, QWP , second polarizer and camera also
as close to the cube as possible (but not touching it).
Laser should be rotated until its polarization direction is at 45 degrees to cube sides.
I will clarify it if needed.

Regards
Vladimir.

Attachment(s) from vladimir galogaza

1 of 1 Photo(s)

2e.

Re: cube beamsplitter for bath PSI

Posted by: "vladimir galogaza" vladimir.galogaza1@zg.t-com.hr   vgalogaza

Tue Sep 13, 2011 5:49 am (PDT)



Julien,

>what is the tolerance in the rotation of the polarizer ?
>I will do it by hand so there will be always a few degrees of error i think.

After Michael wrote PCA program for us, polarizer rotation tolerance is of no issue.
You should cover at least 360 degrees cumulative phase shift with as many
steps as you like. Steps must not be equal.
You should wait after manualy rotating the polarizer to enable vibrations of
interferometer induced by this action to die out.

Regards
Vladimir.
3.

FP interferometer... Tracking Rings

Posted by: "aesbrown77" aesbrown77@yahoo.co.uk   aesbrown77

Tue Sep 13, 2011 3:24 am (PDT)



Hi I wonder if anyone can make some suggestions,

I have a fp with a starting seperation of 10microns and I scan a further 12 microns. I have a point source before the fapry perot at about 500nm and the rings are imaged onto a screen. The rings on the screen are then recorded with a camera.

I wish to scan the mirror and track the movement of each ring.

I can do this for 1 ring, but not if there is more than 1 ring in the image because of the algortihm for finding the circle centre.

My thoughts are first to get the user to frame each ring with a box, optimise the box so it goes through the peak intensities of the ring. Then I would get the box to track the ring it is associated with.

1. does this sound like a good idea?
2. If not, do you have a better idea.
3. FYI I am using Labview.

Thanks for any suggestions
ALex

4a.

Okie Tex?

Posted by: "atmpob" atmpob@yahoo.com   atmpob

Tue Sep 13, 2011 7:50 pm (PDT)



As usually I'm going to the Okie Tex star party and as usual I ask is anyone here going also?

Dale Eason

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