[daip] cross-correlation of theoretical images
Juan-Carlos Algaba-Marcos
algaba at asiaa.sinica.edu.tw
Mon Apr 16 23:24:15 EDT 2012
Dear Amy,
Initially the model was just an image, and hence I thought it would be OK to set any
parameters on it. For example, I do not consider essential to have the right RA, DEC,
and parameters for beam size can also be altered without loss of generality, as far as I
understand. I used the following to make the maps match:
- OGEOM for pixels and peak pixel
- PUTHEAD for map type, coord incr, rotat, flux units
(about conv size and flux units, recall previous question regarding Jy/pixel vs Jy/beam)
Am I doing any wrong assumption here when I think I can manipulate the theoretical image
to match the observed one without loss of generality?
I have tried OHGEO. Here's a sample header for the theoretical image modified by OHGEO:
AIPS 1: Got(1) disk= 2 user=3000 type=MA MODGLJET .OHGEO.2
AIPS 1: Image= (MA) Filename=MODGLJET .OHGEO . 2
AIPS 1: Telescope=VLBI Receiver=VLBI
AIPS 1: Observer= User #= 3000
AIPS 1: Observ. date=05-OCT-2007 Map date=16-APR-2012
AIPS 1: Pixel type: FLOATING Magic value blanking
AIPS 1: Minimum= 1.00000002E+20 Maximum=-1.00000002E+20 JY/BEAM
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
AIPS 1: RA---SIN 102 00 00 00.000 51.00 -0.000002 0.00
AIPS 1: DEC--SIN 102 12 23 59.999 51.00 0.000002 0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 2000.00
AIPS 1: Map type=NORMAL Number of iterations= 100
AIPS 1: Conv size= 0.00002 X 0.00002 Position angle= -23.93
AIPS 1: Observed RA 17 45 40.041 DEC -29 00 28.12
AIPS 1: Maximum version number of extension files of type HI is 1
Both if I use the observed map as a template to interpolate the theoretical one or
vice-versa, the parameters in the header seem to adequately match, but the flux behaves
funny. I have tried in both initial files and files whose header I had already modified
and the problem still remains.
I have also tried HGEOM but the task dies giving the following message:
localh> HGEOM1: Task HGEOM (release of 31DEC11) begins
localh> HGEOM1: You are using a non-standard program
localh> HGEOM1: I WANT TO DIE BUT I CANNOT
localh> HGEOM1: Create ICLJETGL .HGEOM . 1 (MA) on disk 2 cno 52
localh> HGEOM1: Using 12271 words of buffer
localh> HGEOM1: Begin computing coordinate tables
localh> HGEOM1: Begin computing output image
localh> HGEOM1: ***** ALL OUTPUT PIXELS BLANKED *****
localh> HGEOM1: SUBROUTINE MAPIO RETURNED ERROR 16 AT 165
localh> HGEOM1: ILLEGAL WINDOW SPECIFICATION
localh> HGEOM1: DISK 2 SLOT 52 USER 3000 (MA)FILE: ICLJETGL.HGEOM.1
localh> HGEOM1: Destroyed MA image file: catno= 52 disk= 2
localh> HGEOM1: Purports to die of UNNATURAL causes
localh> HGEOM1: localhost 31DEC11 TST: Cpu= 0.0 Real= 0
Still receiving same error even after specifying BLC=1,TRC=120,IMSIZE=120,120 in the
inputs and/or using REMAG files to ensure no blanked pixels are in the image. My guess,
given the two results with HGEOM and OHGEO, is that the headers are properly
interpolated but, for some reason, the output is blanked in both cases, giving the error
above in the case of HGEOM and the strange flux behaviour in the case of OHGEO.
Is it possible that the flux is ill-defined due to the previous issue (convolution and
Jy/pixel to Jy/beam), thus leading to this problem?
CONVL seems to be able to cross-correlate the two maps now but, due to this issue with
the flux, the result obviously does not make any sense.
Thank you very much
JC
---------- Original Message -----------
From:Amy Mioduszewski <amiodusz at nrao.edu>
To:Juan-Carlos Algaba-Marcos <algaba at asiaa.sinica.edu.tw>
Cc:daip at nrao.edu
Sent:Mon, 16 Apr 2012 09:24:17 -0600
Subject:Re: [daip] cross-correlation of theoretical images
> Dear Juan-Carlos,
>
> I'm sorry, our primary expert is away. Did the original pair of images have
> the same geometries? Or did you just force them to be the same? To make the
> image geometries consistent I would recommend using OHGEO.
>
> Also I notice that the RAs are different.
>
> Amy
>
> Juan-Carlos Algaba-Marcos wrote:
> > To whom it may concern,
> >
> > I am lately working on task CONVL with theoretical and observed images. Currently I want
> > to obtain the cross-correlation of a theoretical model and the corresponding synthesized
> > 'observed' one. (OPCODE='IMAC') However, when I try to do so I obtain the following
error:
> >
> > localh> CONVL1: CONFIL: UNEQUAL SPACINGS IN TWO MAPS
> > localh> CONVL1: IMAGE= 0.0000 0.0000 CONV. FN= 0.0000 0.0000
> > localh> CONVL1: Destroyed MA image file: catno= 39 disk= 2
> > localh> CONVL1: Purports to die of UNNATURAL causes
> > localh> CONVL1: localhost 31DEC11 TST: Cpu= 0.0 Real= 0
> >
> > As the first image is a model, I have removed the blanks with task REMAG and adjusted
> > all values to match the observed image with PUTHEAD. Here are the headers of both input
> > images:
> >
> > MODEL
> >
> > AIPS 1: Image= (MA) Filename=MODGLJET .REMAG . 3
> > AIPS 1: Telescope=VLBI Receiver=VLBI
> > AIPS 1: Observer= User #= 3000
> > AIPS 1: Observ. date=05-OCT-2007 Map date=16-APR-2012
> > AIPS 1: Minimum= 1.71167770E-07 Maximum= 3.32765914E-02 JY/BEAM
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
> > AIPS 1: RA---SIN 102 17 45 40.041 51.00 -0.000002 0.00
> > AIPS 1: DEC--SIN 102 -29 00 28.118 51.00 0.000002 0.00
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Coordinate equinox 2000.00
> > AIPS 1: Map type=NORMAL Number of iterations= 100
> > AIPS 1: Conv size= 0.00002 X 0.00002 Position angle= -23.93
> > AIPS 1: Maximum version number of extension files of type HI is 1
> >
> >
> > OBSERVED:
> >
> > AIPS 1: Image= (MA) Filename=ICL JETGL .REMAG . 2
> > AIPS 1: Telescope= Receiver=
> > AIPS 1: Observer= User #= 3000
> > AIPS 1: Observ. date=01-JAN-2000 Map date=16-APR-2012
> > AIPS 1: Minimum=-1.13594451E-03 Maximum= 4.81160544E-02 JY/BEAM
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
> > AIPS 1: RA---SIN 102 00 00 00.000 51.00 -0.000002 0.00
> > AIPS 1: DEC--SIN 102 12 23 59.999 51.00 0.000002 0.00
> > AIPS 1: FREQ 1 2.3000000E+11 1.00 1.0000000E+09 0.00
> > AIPS 1: STOKES 1 -1.0000000E+00 1.00 1.0000000E+00 0.00
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Coordinate equinox 2000.00
> > AIPS 1: Map type=NORMAL Number of iterations= 1913
> > AIPS 1: Conv size= 0.00002 X 0.00002 Position angle= -23.93
> > AIPS 1: Maximum version number of extension files of type HI is 1
> > AIPS 1: Maximum version number of extension files of type CC is 1
> > AIPS 1: Keyword = 'MAXABSU ' value = 2.242303E+10
> > AIPS 1: Keyword = 'MAXBLINE' value = 2.242303E+10
> >
> > I have modified the map type (hence, iterations), conv size, coord increase, size of the
> > model. However, after matching all these, I still keep receiving the same error when
> > trying to cross-correlate.
> >
> > I have found the same problem with OPCODE 'IMAG', but everything runs fine when I use
> > OPCODE 'DGAU' or I try to autocorrelate the same image. Where can the problem be?
> >
> > Thank you very much
> >
> > _______________________________________________
> > Daip mailing list
> > Daip at listmgr.cv.nrao.edu
> > http://listmgr.cv.nrao.edu/mailman/listinfo/daip
> >
------- End of Original Message -------
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