% @(#)fit_mosa.hlq 17.1.1.1 (ESO-SDAG) 01/25/02 17:48:53 %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %.COPYRIGHT (c) 1995 European Southern Observatory %.IDENT fit_mosa.hlq %.AUTHOR RHW, IPG/ESO %.KEYWORDS MIDAS, ccd package, FIT/CCD %.PURPOSE On-line help file for the command: FIT/CCD %.VERSION 950724 RHW created %--------------------------------------------------------------------- \se SECTION./MOSAIC \es\co FIT/MOSAIC 20-Sep-1995 RHW \oc\su FIT/MOSAIC in_frm in_msk in_tab out_frm [match] [nxrsub,nyrsub] [xref,yref] [x_size,y_size] Align and match the elements of the mosaiced frame \up\sy\us\pu Purpose: Align and match the elements of the mosaiced frame \up\sy Syntax: FIT/MOSAIC in_frm in_msk in_tab out_frm [match] [nxrsub,nyrsub] [xref,yref] [x_size,y_size] \ys\pa in_frm= The mosaiced frame to be aligned. This frame must have been produced by the CREATE/MOSAIC command. \ap\pa in_msk= A input image containing information which of the pixels of the input subrasters are considered bad and hence should be excluded for the matching process. Valid data points should have the values 1. The size of the image must the identical to the size of the individual input subrasters. Default all pixels should be used. \ap\pa in_tab= The database table from the CREATE/MOSAIC task. This table contains all relevant information about the subrasters and the way the mosaic is built. \ap\pa out_frm= The aligned output frame produced by the command. No default. \ap\pa match= Match intensities using the overlap region between adjacent subrasters. The median intensity is computed in the overlap region and the intensity scale of the current subraster is scaled to that of the previous subraster. Intensities are matched in two dimensions, first in the order in which they were placed in the output image and then in the orthogonal dimension. The default is "*", i.e. match everything. Those subrasters to be matched must be listed by number. For example to match intensities for subrasters 1 to 5, 10 and 20 set match = "1:5,10,20". To match all the subrasters set match = "*". \ap\pa nxrsub,nyrsub= The column and row index of the reference subraster. This will default to the central subraster. \ap\pa xref,yref= The x and y offset of the destination in the output frame of the reference subraster. By default the reference subraster occupies the same position in the output frame that it does in the input frame. \ap\pa nocols,norows= The number of columns and lines in the output frame. The defaults are the number of columns and lines in the input frame. \ap\no Note: Like the ALIGN and MATCH commands, FIT/MOSAIC is controlled by the input parameters and an additional number of CCD keywords: \\ MO_TRIM - the number of columns or rows to trim off each edge of each input subraster before inserting it in the output frame. The default is to trim 1 column or row at each edge.\\ MO_INTER - The type of interpolant use to shift the subraster. Possible options area : nearest, linear, poly3, poly5, and spline3.\\ MO_BLANK - to define the pixel intensity in undefined regions. \\ FIT/MOSAIC is able to a mosaicing process taking into account all information that is available to determine the best estimate for the offsets between the individual frames. Rather then having a bootstrap approach like in the command MATCH/MOSAIC the FIT/MOSAIC command uses all offsets between all frames. \\ The commands does the mosaicing in a two step approach. The first one is to determine the offset between the single subraster in their overlapping regions. In the second step this information is then used to do a least square fit. \\ In the first step the overlapping areas are obtain from the input database table. Within the overlapping regions the median intensities are determined and the offsets of these median values calculated. Bad pixels indicated by the bad pixel input image will not be taken into account. Also, a pixel will only be used in the calculation of the median if its corresponding pixel is also used in the other frame. \\ In the second step the relative offsets are used to determine the best fitting background offset for each frame. Using the "match" input parameter the user can excluded one or more subrasters from the fit. In addition to the output file, the command will output the offset for each subraster and the square root of the sum of the residuals and the standard deviation of the residuals. From this information bad subraster can be identified and excluded from the fit. The best result may been obtained by continuing this process until all frames more than 3 sigma above the mean have been excluded. \\ \on\see See also: SET/CCD, SHOW/CCD, CREATE/MOSAIC, SHIFT/MOSAIC, ALIGN/MOSAIC, MATCH/MOSAIC \ees\exs Examples: \ex FIT/MOSAIC mosin ? mosdb mosout Align and match the mosin frame with respect to default reference subraster. Use the table mosdb for getting the overlap regions. The output frame is mosout. All pixels will be taken into account. \xe\ex FIT/MOSAIC mosin mosmsk mosdb mosout 3,4 6,5 The same as above but the reference frame in the mosaic is now (subx=6, suby=5). The vaid pixels will bne taken from the mask mosmsk. the subrasters 3 and 4 will not be taken into account in the fitting. \xe \sxe