% @(#)centergaus.hlq 17.1.1.1 (ESO-IPG) 01/25/02 17:43:18 %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %.COPYRIGHT (c) 1990 European Southern Observatory %.IDENT centergaus.hlq %.AUTHOR KB, IPG/ESO %.KEYWORDS MIDAS, help files, CENTER/GAUSS %.PURPOSE On-line help file for the command: CENTER/GAUSS %.VERSION 1.0 07-FEB-1990 : Creation, KB %.VERSION 1.1 02-MAR-1992 : Update, KB %.VERSION 1.2 09-NOV-1992 : Update, KB %---------------------------------------------------------------- \se SECTION./GAUS \es\co CENTER/GAUSS 29-JUL-1999 KB \oc\su CENTER/GAUSS [in_specs] [out_specs] [out_opt] [curs_specs] [wsize] [zw_option] [invert_flag] find intensity weighted center \us\pu Purpose: Compute the central position of the specified object by fitting a Gaussian to the marginal distributions in both the x- and y-directions (or just in x). \up\sub Subject: Position, fitting, centering. \bus\sy Syntax: CENTER/GAUSS [in_specs] [out_specs] [out_opt] [curs_specs] [wsize] [zw_option] [invert_flag] \ys\pa in_specs = input specifications, either \\ (a) CURSOR - if the subimages are interactively chosen via the cursor rectangle, or \\ (b) GCURSOR - if the subimages are interactively chosen via the graphic cursor, or \\ (c) image,table - if the subimages are defined in a table in the columns labeled :XSTART, :XEND, :YSTART and :YEND, or only columns :XSTART and :XEND (1-dim centering) or only single column :X_POSITION (two rows per interval needed); \\ (d) image - if subimage will be a (max) 200 * 200 window around center of image \\ (e) image,xfrpix,yfrpix - if subimage will be a window of `wsize' around xfrpix,yfrpix (frame pixels) \\ defaulted to CURSOR \ap\pa out_specs = output specifications: \\ (x) table name, may be same as given in in_specs \\ (y) if same table, only the xcenter, ycenter, xerr, yerr, xsigma, ysigma, xfwhm, yfwhm, icent and status will be stored in columns \\ :XCEN, :YCEN, :XERR, :YERR, :XSIG, :YSIG, :XFWHM :YFWHM :ICENT :STATUS \\ if new table, then in addition to the columns explained above, also the columns labeled :XSTART, :YSTART, :XEND, :YEND and :NO will be filled \\ (z) descriptor,D if the results should be stored in a real descriptor of the involved image frame; \\ data will be stored as xstart, ystart, xend, yend, xcenter, ycenter, xerr, yerr, xsigma, ysigma, return_status, xfwhm, yfwhm and icent \\ Per Default the values are displayed only on the terminal and stored in the keyword OUTPUTR which is filled as follows: xstart, ystart, xend, yend, xcenter, ycenter, xerr, yerr, xsigma, ysigma, return_status, xfwhm, yfwhm, icent \\ Xstart, ystart, xend, yend, xcenter, ycenter are also stored as double precision values in keyword OUTPUTD(1 - 6). \ap\pa out_opt = A, append data to a table (or descriptor), else start at the beginning, only applicable to (x) or (z) \\ ID, write also column labeled :IDENT to output table, only applicable to (x) \\ EMISSION, assumes emission lines, applicable to (b) \\ ABSORPTION, assumes absorption lines, applicable to (b) \ap\pa curs_specs = no_curs,drawflag,max_input: \\ no_curs = 1 or 2, if single cursor a fixed subimage according to next parameter `wsize' is used; for 2 cursors the size of subimage is determined by the size of the cursor rectangle. \\ drawflag = option for drawing subwindow limits in the overlay channel; \\ max_input = max. of cursor inputs. \\ This parameter is only used if in_specs = CURSOR (a); \\ defaulted to 2,1,9999 \ap\pa wsize = no. of x-and y-pixels for subwindow centered via the single cursor or `inp_specs' (e); \\ defaulted to 50,50 \ap\pa zw_option = zwindow_flag,zoom; \\ zwindow_flag = W for zoom window, N for none, \\ zoom = initial zoom factor; \\ only applicable to X11 window displays and option (a), \\ defaulted to N,4 (see the help of GET/CURSOR for more info about the additional functionality provided in that mode); \ap\pa invert_flag = YES or NO; \\ if the objects are at a minimum and not maximum of the data, i.e. instead of a Gaussian `peak' you have a Gaussian `valley', set this par. to YES. \\ defaulted to NO \ap\sa See also: CENTER/MOMENT, CENTER/IQE, MAGNITUDE/CENTER \as\no Note: When using the cursor input option, a cursor window will appear on the screen. \\ For X-Windows use the mouse to move the complete window (or single cursor), use the arrow keys to change window size. Left mouse button (or RETURN key) is ENTER button, right button is EXIT button. \\ If you also use the `zw_option', the cursor in the main display is only used to define the subwindow to work on. Then move the cursor to the auxiliary (zoom) window and proceed as described above. \\ When using the graphic cursor option (b), the command needs two cursor positions defining the 1D interval to be used. Any key can be used to input the cursor. Use SPACE-BAR to exit. \\ Also be aware the fitted will be done on the LAST plotted data. I.e. when addtional data is plotted using an overplot command the CENTER command will work on this overplotted data set. \\ When using the out_opt ID for table output, computations proceed after pressing the ENTER button and(!) entering also an identifier of max. 8 characters and hitting RETURN on the keyboard. Otherwise the string IDabcd will be written into column :IDENT with "abcd" the sequence number. \\ The return status from the centering algorithm is specified as follows: \\ < 0 = estimation failed 0 = O.K. 1 = ambiguous sources 2 = no source 3 = iteration failed > 3 = routine error \\ If you also need the angle of the 2-dim Gaussian (if it's not perfectly round) of the major axis with the X-axis, use the command CENTER/IQE (ImageQualityEstimate). \on\exs Examples: \ex 1) CENTER/GAUSS Use cursor to define subimages and display start- and end-coordinates of subimage as well as center values and associated errors and return status on terminal only \xe\ex 2) CENTER/GAUSS CURSOR values,d as 1) but write data to beginning of real descriptor VALUES of displayed image \xe\ex 3) CENTER/GAUSS cursor VALUES,D A as 2) but append data to the end of real descriptor VALUES \xe\ex 4) CENTER/GAUSS CURSOR values as 1) but store data into table values.tbl (will be created by MIDAS) \xe\ex 6) CENTER/GAUSS ccd001,sources use columns :XSTART, :YSTART, :XEND and :YEND of `sources.tbl' to define the subimages of image ccd001.bdf; just display results \xe\ex 7) CENTER/GAUSS ccd001,sources VALUES,D as 6) but write results into real descr values of frame `ccd001.bdf' \xe\ex 8) CENTER/GAUSS ccd001,sources sources as 6) but store results also in input table sources.tbl \xe\ex 9) CENTER/GAUSS ccd001,sources center as 8) but store results into new table `center.tbl' \xe\ex 10) CENTER/GAUSS ccd001,233,402 ? ? ? 20,20 use a subwindow of 20x20 pixels centered at frame pixels 233,402 of `ccd001.bdf' \xe\ex 11) CENTER/GAUSS cursor p6=w as 1) but use zoom window to determine working area via cursor, but we need X11 for that... \xe\ex 12) CENTER/GAUSS GCURSOR table EMISSION generate table `table.tbl' with positions of emission lines defined with the graphic cursor. \xe \sxe