Main Page | Modules | Data Structures | File List | Data Fields | Globals | Related Pages

center_gauss

Fit a simple 2D-gaussian on input image to get rough position/width.

Parameters:
-in none Input frame
-nobkgnd No-background flag
-dev ASCII Output device or filename (see Graphical output)
-cuts 15,99 Background frame cuts (in % of histogram)
-center x0,y0 Centroid initial estimate
-nofit No fit done (display only)
-circle X,Y,R Display circle of center X,Y and radius R
-axisym Fit an axisymmetric 2D-gaussian (default is a X-Y 2D-gaussian)
-hsize 0 Restrict the fitting window around estimated center (half-size in px, default is 0, i.e. fit the whole image)
Returns:
Error status
Note:
Use with the -quiet standard option for minimal output. For a non-axisymmetric gaussian,
 X  Y  dX  dY
 I dI
 Sx Sy dSx dSy
 B dB
where X,Y,I,Sx,Sy and B are respectively the gaussian position, intensity, dispersions and background, and dX, etc. are the associated formal errors. Two 6-DOUBLE keywords, CENGAUS and ERRGAUS, are added to the input frame, and filled-in with the results and errors in the same order.

This fitting routine is definitely not very robust: it can be easily fooled by a bright secondary peak (e.g. a cosmic peak or the galaxy nucleus).

Todo:
Use image centroid (and not max) as first guess.

Should unify with Fit_Xpeak using an intermediate 2D-array.


Generated on Thu Oct 27 00:00:24 2005 for Snifs by doxygen 1.3.5