From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- pkg/images/immatch/doc/linmatch.hlp | 699 ++++++++++++++++++++++++++++++++++++ 1 file changed, 699 insertions(+) create mode 100644 pkg/images/immatch/doc/linmatch.hlp (limited to 'pkg/images/immatch/doc/linmatch.hlp') diff --git a/pkg/images/immatch/doc/linmatch.hlp b/pkg/images/immatch/doc/linmatch.hlp new file mode 100644 index 00000000..21c04b22 --- /dev/null +++ b/pkg/images/immatch/doc/linmatch.hlp @@ -0,0 +1,699 @@ +.help linmatch Apr95 images.immatch +.ih +NAME +linmatch -- linearly match the intensity scales of 1 and 2D images +.ih +USAGE +linmatch input reference regions lintransform +.ih +PARAMETERS +.ls input +The list of input images to be matched. +.le +.ls reference +The list of reference images to which the input images are to be matched +if \fIscaling\fR is one of the "mean", "median", "mode", or "fit" +algorithms, or the list of reference photometry files if \fIscaling\fR +specifies the "photometry" algorithm. The number of reference images or +reference photometry files must be one or equal to the number of input +images. +.le +.ls regions +The list of image regions used to compute the intensity +matching function if \fIscaling\fR is one of the "mean", "median", "mode", +or "fit" algorithms, or a list of the input photometry files if +\fIscaling\fR specifies the "photometry" algorithm. In the former +case \fIregions\fR may be: 1) a string of the form "grid nx ny" defining +a grid of nx by ny equally spaced and sized image regions spanning the +entire image, 2) a list of object coordinates separated by commas e.g. +"303 401, 131 202", 3) a list of image sections separated by whitespace +e.g "[101:200,101:200] [301:400,301:400]", +4) the name of a text file containing a list of object coordinates separated +by newlines, and 5) the name of a text file containing a list of image +sections separated by whitespace and/or newlines. +.le +.ls lintransform +The name of the text file where the computed scaling factors are written. +If \fIdatabasefmt\fR is "yes", a single record containing the computed +bscale and bzero factors for each image region or object, and the +average bscale and bzero, is written to the text database +file for each input image. If \fIdatabasefmt\fR = "no", a single line +containing the input image name, bscale factor, bzero factor, error +in bscale, and error in bzero is written to a simple text file for +each image. +.le +.ls output = "" +The list of output matched images. If \fIoutput\fR is the NULL string +then bscale and bzero are computed for each input image and written to +\fIlintransform\fR, but no output images are written. If \fIoutput\fR +is not NULL then the number of output images must equal the number of +input images. +.le +.ls databasefmt = yes +If \fIdatabasefmt\fR is "yes" the computed bscale and bzero factors +are written to a text database file, otherwise they are written to a +simple text file. +.le +.ls records = "" +The list of records to be written to or read from \fIlintransform\fR one +input image. If \fIrecords\fR is NULL then the output or input record names +are assumed to be the names of the input images. If \fIrecords\fR is not NULL +then the record names in \fIrecords\fR are used to write / read the +database records. This parameter is useful for users +who, wish to compute the bscale and bzero factors using images that have +been processed +in some manner (e.g. smoothed), but apply the computed bscale and bzero +factors to the original unprocessed images. If more than one record +with the same name exists in \fIlintransform\fR then the most recently written +record takes precedence. The records parameter is ignored if +\fIdatabasefmt\fR is "no". +.le +.ls append = yes +Append new records to an existing \fIlintransform\fR file or start a new +file for each execution of LINMATCH? The append parameter is +ignored if \fIdatabasefmt\fR is "no". +.le +.ls shifts = "" +An optional list of shifts files containing the x and y shifts to be applied +to the reference regions to determine their positions in +the input images. The number of shifts files must equal the number of +reference images. The shifts are listed in the shifts file, 1 shift per line, +with the x and y shifts in +columns 1 and 2 respectively. If there are fewer x and y shifts defined +in the shifts file than there are input images, the extra input +images will be assigned x and y shifts of \fIxshift\fR and \fIyshift\fR +respectively. The shifts parameter is ignored if the \fIscaling\fR +parameter is set to "photometry". +.le +.ls xshift = 0.0 yshift = 0.0 +The default x and y shifts to be applied to the reference image regions +or objects to compute their positions in the input image. +Values in \fIshifts\fR take precedence over the values of \fIxshift\fR and +\fIyshift\fR. xshift and yshift are ignored if the \fIscaling\fR parameter +is set to "photometry". +.le +.ls dnx = 31 dny = 31 +The default size of a single image region used to compute the bscale +and bzero factors if \fIscaling\fR is one of the "mean", "median", "mode", +or "fit" algorithms and \fIregions\fR is a coordinate list rather than +a sections list. dnx and dny are ignored if the \fIscaling\fR parameter +is set to "photometry". +.le +.ls maxnregions = 100 +The maximum number of image regions or objects with measured photometry +that can be used to compute the bscale and bzero factors. +.le +.ls scaling = "mean mean" +The algorithms used to compute the bscale and bzero factors respectively. +The options are: +.ls mean median mode +Bscale or bzero are computed using the "mean", "median", or "mode" statistic +for each input and reference region individually. If one of the bscale or +bzero fitting +algorithms is set to "mean", "median", or "mode", the remaining factor +must be set to "mean", "median" or "mode" or a numerical constant, +e.g. "mean mean", "mean -100.0" or "2.63 mode". +If both algorithms are set to "mean", "median", or "mode" bscale will be +computed using the specified statistic and bzero will be set to 0.0 +If more than one input region is defined then a weighted least squares +fit of the reference statistics to the input image statistics +is performed and used to compute the final bscale and bzero factors. +.le +.ls fit +Bscale and bzero are computed for each input image region individually +by performing a least squares fit of the reference image pixels to +the input image pixels. If more than one input image region is defined +the final bscale and bzero factors are computed by averaging, +weighted by their signal-to-noise ratios, the individual bscale and bzero +values. If one of the bscale or bzero fitting +algorithms is set to "fit", the remaining factor must either also +be computed with the "fit" algorithm or set to a numerical constant, +e.g. "fit fit", "fit -100.0", or "2.63 fit". +.le +.ls photometry +Bscale and/or bzero are computed for each input object individually +using photometry computed for a set of objects common to the reference +and input images. If more than one input object is defined +the final bscale and bzero factors are computed by averaging, +weighted by their signal-to-noise ratios, the individual bscale and bzero +values. If one of the bscale or bzero fitting +algorithms is set to "photometry", the remaining factor must either also +be computed with the "photometry" algorithm or set to a numerical +constant, e.g. "photometry photometry", "photometry -100.0", or +"2.63 photometry". +.le +.ls number +Bscale and/or bzero are set to user defined numerical constants, +e.g. "2.62 -55.0" or "2.62 median". If both bscale and bzero are numerical +constants, LINMATCH must be run in non-interactive mode. If only one of bscale +or bzero is a numerical constant, any of the "mean", "median", "mode", "fit", +or "photometry" algorithms may be used to compute the remaining factor. +.le +.ls file +Bscale and bzero are not computed but instead read from record \fIrecord\fR in +the text database file \fIlintransform\fR if \fIdatabasefmt\fR is "yes", +or the next line of a simple text file if \fIdatabasefmt\fR is "no". +.le + +Further description of the matching algorithms can be found in the ALGORITHMS +section. +.le +.ls datamin = INDEF datamax = INDEF +The minimum and maximum good data values. Datamin and datamax are used by +the "mean", "median", and "mode" scaling algorithms to reject entire +image regions from the final fit, and by the "fit" algorithm to reject +individual bad pixels from the least squares fits for the individual +regions. +.le +.ls maxiter = 10 +The maximum number of iterations performed by the least squares fitting +algorithm. +.le +.ls nreject = 0 +The maximum number of rejection cycles used to detect and reject bad pixels +from the fit if the scaling algorithm is "fit" or bad regions / objects +from the fit if the scaling algorithm is "mean", "median", "mode", "fit", +or "photometry". +.le +.ls loreject = INDEF hireject = INDEF +The high- and low-side bad data rejection limits used to detect and reject +deviant pixels from the fit if the scaling algorithm is "fit" or bad +regions / objects from the fit if the scaling algorithm is "mean", "median", +"mode", "fit", or "photometry". +.le +.ls gain = "1.0 1.0" readnoise = "0.0 0.0" +The reference and input image gain and readout noise in e-/ADU and +e- respectively. Gain and readout may be numerical constants or the +image header keyword containing the actual gain and/or readout noise +value. Gain and readnoise are used by the "mean", "median", "mode", +and "fit" algorithms to estimate the expected errors in the computed +"mean", "median", or "mode" statistics, and by the "fit" algorithm +to compute the per pixel errors values. +.le +.ls interactive = no +Compute the bscale and bzero scaling factors for each image interactively +using graphics cursor and optionally image cursor input. +.le +.ls verbose = yes +Print messages about the progress of the task during task execution in +non-interactive mode. +.le +.ls graphics = "stdgraph" +The default graphics device. +.le +.ls display = "stdimage" +The default image display device. +.le +.ls gcommands = "" +The default graphics cursor. +.le +.ls icommands = "" +The default image cursor. +.le + +.ih +DESCRIPTION + +LINMATCH computes the bscale and bzero factors required to match +the intensity scales of a list of input +images \fIinput\fR to the intensity scales of a list of reference +images \fIreference\fR using the following definition of +bscale and bzero and a variety of techniques. + +.nf + reference = bscale * input + bzero +.fi + +The computed bscale and bzero factors are stored +in the text file \fIlintransform\fR, in the record \fIrecords\fR if +\fIdatabasefmt\fR is "yes", or a single line of a simple text file +if \fIdatabasefmt\fR is "no". One record is written to the output file +file for each input image. If a non NULL list of output images +\fIoutput\fR is supplied, a scaled output image is written for +each input image. LINMATCH is intended to solve 1D and 2D image intensity +matching problems where the input and reference images: 1) have the same +pixel scale and orientation, 2) differ in intensity by at most a scale +factor and a zero point, and 3) contain one or more regions or objects in +common that can be used to compute the scaling factors. Some of the scaling +algorithms also require that the images registered and have identical +point spread functions. LINMATCH cannot be used to compute or apply non-linear +intensity matching functions. + +If \fIscaling\fR = "mean", "median", "mode", or "fit" bscale and bzero +are computed directly from the input and reference image data using the +image sections specified in the \fIregions\fR and one of the above fitting +techniques as described in the ALGORITHMS section. All four algorithms +require accurate knowledge of the measurement errors which in turn +require accurate knowledge of the input and reference image gain and +readout noise values. Gain and readout noise values can be entered by +setting the \fIgain\fR and \fIreadnouse\fR parameters to the appropriate +numerical values or image header keyword. + +\fIRegions\fR is interpreted as either: 1) a string of +the form "grid nx ny" specifying a list of nx by ny image sections +spanning the entire image, 2) a string defining the coordinates of a list +of objects separated by commas e.g. +"103.3 189.2, 204.4 389.7", 3) a string containing a list of image +sections separated by whitespace, e.g "[100:203,200:300] [400:500,400:500]" +4) the name of a text file containing the coordinates of one or +more objects, one object per line, with the x and y coordinates +in columns 1 and 2 respectively, 5) the name of a text +file containing a list of image sections separated by whitespace and/or +newlines. The image sections specifications, or alternatively +the object coordinates and the parameters \fIdnx\fR and \fIdny\fR, +determine the size of the input and reference image data regions to be +extracted and used to compute the bscale and bzero factors. +These image regions should be selected with care. Ideal regions +span a range of intensity values and contain both object and background +data. + +If \fIscaling\fR = "photometry", the bscale and bzero factors +are computed directly from data in the input and reference image photometry +files using the technique described in the ALGORITHMS section. +In this case \fIregions\fR is a list of the input image photometry +files and \fIreference\fR are the corresponding reference image +photometry files written by a separate photometry task. +These photometry files are simple text files with the object +sky values, errors in the sky values, magnitudes, and errors in the +magnitudes in columns 1, 2, 3, and 4 respectively. + +An image region is rejected from the fit if it contains data outside the +limits specified by the \fIdatamin\fR and \fIdatamax\fR parameters +and \fIscaling\fR = +"mean", "median", or "mode". A pixel is rejected from the fit for an +individual region if the pixel value is outside the limits specified +by datamin and datamax, and the scaling algorithm is "fit". The datamin +and datamax parameters are not used by the "photometry" scaling algorithm . + +Deviant pixels can be rejected from the fits to individual image regions +if \fIscaling\fR = "fit", and \fInreject\fR, \fIloreject\fR, and +\fIhireject\fR are set appropriately. Nreject, loreject and reject +are also be used by all the scaling algorithms to reject image regions +which contribute deviant bscale and bzero values. + +The computed bscale and bzero value for each region and the final bscale +and bzero value for each input image are written to the linear +transformation file \fIlintransform\fR. +If \fIdatabasefmt\fR is "yes" each result is written to a record whose name +is either identical to the name of the input +image or supplied by the user via the \fIrecords\fR parameter . +If \fIdatabasefmt\fR is "no", then a single line containing the input image +name and the computed bscale and bzero values and their errors +is written to the output shifts file. + +If a list of output image names have been supplied then the bscale and +bzero values will be applied to the input images to compute the output images. + +If the \fIscaling\fR parameter is set to "file" then the shifts +computed in a previous run of LINMATCH will be read from the \fIlintransform\fR +file and applied to the input images to compute the output images. +If no record list is supplied by the user LINMATCH will +search for a record whose name is the same as the input image name. If more than +one record of the same name is found then the most recently written +record will be used. + +In non-interactive mode the task parameters are set at task startup time +and the input images are processed sequentially. If the \fIverbose\fR +flag is set, messages about the progress of the task are printed on the +screen as the task is running. + +In interactive mode the user can mark the regions to be used +to compute the matching function on the image display, show/set the data +and algorithm parameters, compute, recompute, and plot +matching function, and interactively delete and undelete +bad data from the fits using the plots and graphics cursor. A summary +of the available interactive commands is given in the CURSOR COMMANDS +section. + +.ih +CURSOR COMMANDS + +.nf +The following graphics cursor commands are currently available in LINMATCH. + + Interactive Keystroke Commands + +? Print help +: Colon commands + +g Draw a plot of the current fit +i Draw the residuals plot for the current fit +p Draw a plot of current photometry +s Draw histograms for the image region nearest the cursor +l Draw the least squares fit for the image region nearest the cursor +h Draw histogram plot of each image region in turn +l Draw least squares fits plot of each image region in turn +r Redraw the current plot +d Delete the image region nearest the cursor +u Undelete the image region nearest the cursor +f Recompute the intensity matching function +w Update the task parameters +q Exit + + + Colon Commands + +:markcoords Mark objects on the display +:marksections Mark image sections on the display +:show Show current values of all the parameters + + Show/set Parameters + +:input [string] Show/set the current input image +:reference [string] Show/set the current reference image / phot file +:regions [string] Show/set the current image regions +:photfile [string] Show/set the current input photometry file +:lintransform [string] Show/set the linear transform database file name +:dnx [value] Show/set the default x size of an image region +:dny [value] Show/set the default y size of an image region +:shifts [string] Show/set the current shifts file +:xshift [value] Show/set the input image x shift +:yshift [value] Show/set the input image y shift +:output [string] Show/set the current output image name +:maxnregions Show the maximum number of objects / regions +:gain [string] Show/set the gain value / image header keyword +:readnoise [string] Show/set the readout noise value / image header + keyword + +:scaling Show the current scaling algorithm +:datamin [value] Show/set the minimum good data value +:datamax [value] Show/set the maximum good data value +:nreject [value] Show/set the maximum number of rejection cycles +:loreject [value] Show/set low side k-sigma rejection parameter +:hireject [value] Show/set high side k-sigma rejection parameter +.fi + +.ih +ALGORITHMS + +MEAN, MEDIAN, AND MODE + +For each input and reference image region the mean, median, mode, statistic +and an error estimate for that statistic are computed as shown below, +mstat is for mean, median, or mode statistic, emstat stands for the error +estimate, stdev for the measured standard deviation, and npix for the +number of points. + +.nf + mstat = mean, median, or mode + emstat = min (sqrt (mean / gain + readnoise ** 2 / gain ** 2), + stdev / sqrt(npix)) +.fi + +If only a single image region is specified then mstat is used to compute +one of bscale or bzero but not both as shown below. Bscale is computed by +default. + +.nf + bscale = mstat[ref] / mstat[input] + err[bscale] = abs (bscale) * sqrt (emstat[ref] ** 2 / mstat[ref] ** 2 + + emstat[input] ** 2 / mstat[input] ** 2) + bzero = constant + err[bzero] = 0.0 + + bzero = mstat[ref] - mstat[input] + err[bzero] = sqrt (emstat[ref] ** 2 + emstat[input] ** 2) + bscale = constant + err[bscale] = 0.0 +.fi + +If more than one image region is defined then the computed mean, median, +or mode values for the input and reference image regions are used as +shown below to compute the bscale and bzero factors and their errors +using a weighted least squares fit. + +.nf + mstat[ref] = bscale * mstat[input] + bzero +.fi + +If an image region contains data outside the limits defined +by \fIdatamin\fR and \fIdatamax\fR that image region is eliminated +entirely from the fit. + +The parameters \fInreject\fR, \fIloreject\fR, +and \fIhireject\fR are used to detect and automatically eliminate +deviant data points from the final least squares fit. If for some reason +bscale or bzero cannot be fit, default values of 1.0 and 0.0 are +assigned. + +The mean, median, and mode algorithms depend on the global properties of +the image regions. These algorithms do require the reference and +input images to have the same pixel scale and orientation, +but do not automatically require the reference and input images +to have the same point spread function. Small shifts between the reference +and input images can be removed using the \fIshifts\fR, \fIxshift\fR, and +\fIyshift\fR parameters. + +If the image regions contain stars, then either regions should be large +enough to include all the flux of the stars in which case the images +do not have to have the same psf, or the psfs should be the same so +that same portion of the psf is sampled. The best image regions for +matching will contain object and background information. + +FIT + +For each input and reference image the bscale and bzero factors are +computed by doing a pixel to pixel weighted least squares fit of the reference +image counts to the input image counts as shown below. + +.nf + counts[ref] = bscale * counts[input] + bzero + weight = 1.0 / (err[ref] ** 2 + bscale ** 2 * err[input] ** 2) + err[ref] = sqrt (counts[ref] / gain[ref] + readnoise[ref] ** 2 / + gain[ref] ** 2) + err[input] = sqrt (counts[input] / gain[input] + + readnoise[input] ** 2 / gain[input] ** 2) +.fi + +The fitting technique takes into account errors in both the reference and +input image counts and provides an error estimate for the computed bscale +and bzero factors. Bad data are rejected +automatically from the fit by setting the \fIdatamin\fR and \fIdatamax\fR +parameters. Deviant pixels are rejected from the fit by setting the +\fInreject\fR, \fIloreject\fR, and \fIhireject\fR parameters appropriately. + +The final bscale and bzero for the input image are computed by calculating +the average weighted by their errors of the individual bscale and bzero +values. The parameters \fInreject\fR, \fIloreject\fR, and \fIhirject\fR +can be used to automatically detect and reject deviant points. + +The fit algorithm depends on the results of pixel to pixel fits in +each reference and input image region. The technique requires that the +images be spatially registered and psfmatched before it is employed. +Each input and reference image should contain a range of pixel intensities +so that both bscale and bzero can be accurately determined. + +PHOTOMETRY + +For each object common to the reference and input photometry files +the input sky values sky, errors in the sky values serr, +magnitudes mag, and magnitude errors merr are used to compute the +bscale and bzero factors and estimate their errors as shown +below. + +.nf + bscale = 10.0 ** ((mag[ref] - mag[input]) / 2.5) + bzero = sky[ref] - bscale * sky[input] + err[bscale] = 0.4 * log(10.0) * bscale * sqrt (merr[ref] ** 2 + + magerr[input] ** 2)) + err[bzero] = sqrt (serr[ref] ** 2 + err[bscale] ** 2 * + sky[input] ** 2 + bscale ** 2 * sky[input] ** 2) +.fi + +The final bscale and bzero for the input image are computed by calculation +the average of the individual bscale and bzero values weighted by their +errors. The parameters \fInreject\fR, \fIloreject\fR, and \fIhirject\fR can +be used to automatically detect and reject deviant points. + +THE LEAST SQUARES FITTING TECHNIQUE + +The least squares fitting code performs a double linear regression on +the x and y points, taking into account the errors in both x and y. + +The best fitting line is the defined below. + +.nf + y = a * x + b +.fi + +The error ellipses are + +.nf + S = (x - xfit) ** 2 / err[x] ** 2 + (y - yfit) ** 2 / + err[y] ** 2 +.fi + +where S is the quantity to be minimized. Initial values of a and b are +estimated by fitting the data to a straight line assuming uniform +weighting. The best fit values of a and b are then +determined by iterating on the relationship + +.nf + dy = x' * da + db +.fi + +where da and db are corrections to the previously determined values of a and +b and dy and x' are defined as. + +.nf + dy = y - (ax + b) + x' = x + a * err[x] ** 2 * dy / (a ** 2 * err[x] ** 2 + + err[y] ** 2) +.fi + +The new values of the a and b then become. + +.nf + a = a + da + b = b + db +.fi + +.ih +REFERENCES + +A review of doubly weighted linear regression problems in +astronomy can be found in the paper "Linear Regression in Astronomy. II" +by (Feigelson and Babu (1992 Ap.J. 397, 55). A detailed derivation of the +particular solution used by LINMATCH can be found in the article +"The Techniques of Least Squares and Stellar Photometry with CCDs" +by Stetson (1989 Proceeding of the V Advanced School of Astrophysics, +p 51). + +.ih +EXAMPLES + +1. Match the intensity scales of a list of images to a reference +image using a list of stars on the displayed reference image with +the image cursor and the "mean" scaling algorithm. Assume that none +of the stars are saturated and that a radius of 31 pixels is sufficient +to include all the flux from the stars plus some background flux. +Make sure that the correct gain and readout noise values are in the +image headers. + +.nf + cl> display refimage 1 + + cl> rimcursor > objlist + ... mark several candidate stars by moving the cursor to the + star of interest and hitting the space bar key + ... type EOF to terminate the list + + cl> linmatch @imlist refimage objlist lintran.db \ + out=@outlist dnx=31 dny=31 scaling="mean mean" gain=gain \ + readnoise=readnoise +.fi + +2. Repeat the previous command but force the bzero factor to be -100.0 +instead of using the fitted value. + +.nf + cl> linmatch @imlist refimage objlist lintran.db \ + out=@outlist dnx=31 dny=31 scaling="mean -100.0" \ + gain=gain readnoise=rdnoise +.fi + +3. Repeat the first example but compute bscale and bzero +the bscale and bzero values using boxcar smoothed versions of +the input images. Make sure the gain and readout noise are +adjusted appropriately. + +.nf + cl> linmatch @bimlist brefimage objlist lintran.db \ + dnx=31 dny=31 scaling="mean mean" gain=gain \ + readnoise=rdnoise + + cl> linmatch @imlist refimage objlist lintran.db \ + out=@outimlist records=@bimlist scaling="file file" +.fi + +4. Match the intensity of an input image which has been spatially +registered and psfmatched to the reference image using the "fit" algorithm +and a single reference image region. Remove the effects of saturated +pixels by setting datamax to 28000 counts, and the effects of any deviant pixels +by setting nreject, loreject, and hireject to appropriate values. + +.nf + cl> linmatch image refimage [50:150,50:150] lintran.db \ + out=outimage scaling="fit fit" datamax=28000 nreject=3 \ + loreject=3 hireject=3 gain=gain readnoise=rdnoise +.fi + +5. Repeat the previous example but use several image sections to compute +the bscale and bzero values. + +.nf + cl> linmatch image refimage sections lintran.db \ + out=outimage scaling="fit fit" datamax=28000 nreject=3 \ + loreject=3 hireject=3 gain=gain readnoise=rdnoise +.fi + +6. Match the intensity scales of two images using photometry +computed with the apphot package qphot task. The two images are +spatially registered, psfmatched, and the photometry aperture is sufficient to +include all the light from the stars. The filecalc task used to compute +the error in the mean sky is in the addon ctio package. + +.nf + cl> display refimage 1 fi+ + cl> rimcursor > objlist + ... mark several candidate stars by moving the cursor to the + star of interest and hitting the space bar key + ... type EOF to terminate the list + cl> qphot refimage coords=objlist inter- + cl> qphot image coords=objlist inter- + cl> pdump refimage.mag.1 msky,stdev,nsky,mag,merr yes | filecalc \ + STDIN "$1;$2/sqrt($3);$4;$5" > refimage.phot + cl> pdump image.mag.1 msky,stdev,nsky,mag,merr yes | filecalc \ + STDIN "$1;$2/sqrt($3);$4;$5" > image.phot + cl> linmatch image refimage.phot image.phot lintran.db \ + out=outimage scaling="phot phot" nreject=3 loreject=3\ + hireject=3 +.fi + +7. Register two images interactively using the fit algorithms and +five non-overlapping image regions in the sections file. + +.nf + cl> linmatch image refimage sections lintran.db \ + out=outimage scaling="fit fit" datamax=28000 nreject=3 \ + loreject=3 hireject=3 gain=gain readnoise=rdnoise \ + interactive + + + ... a plot of bscale and bzero versus region number + appears + + ... type ? to get a list of the keystroke and : commands + + ... type i to see a plot of the bscale and bzero residuals + versus region + + ... type g to return to the default bscale and bzero versus + region plot + + ... type l to examine plot of the fits and residuals for the + individual regions + ... step forward and back in the regions list with the + space bar and -keys + ... flip back and forth between the fit and residuals + keys with l and i keys + ... return to the main plot by typing q + + ... return to the residuals plot by typing i and delete a + region with a large residual by moving to the + bad point and typing d + + ... type f to recompute the fit + + ... type q to quit the interactive loop, n to go to the + next image or q to quit the task + +.fi + +.ih +TIME REQUIREMENTS +.ih +BUGS +.ih +SEE ALSO +imexpr, imcombine, ctio.filecalc, apphot.qphot, apphot.phot +.endhelp -- cgit