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diff --git a/pkg/images/immatch/doc/geotran.hlp b/pkg/images/immatch/doc/geotran.hlp new file mode 100644 index 00000000..e3ad15f7 --- /dev/null +++ b/pkg/images/immatch/doc/geotran.hlp @@ -0,0 +1,320 @@ +.help geotran Dec98 images.immatch +.ih +NAME +geotran -- geometrically transform a list of images +.ih +USAGE +geotran input output database transforms +.ih +PARAMETERS +.ls input +List of images to be transformed. +.le +.ls output +List of output images. If the output image name is the same as the input +image name the input image is overwritten. The output image may be a section +of an existing image. The number of output images must equal the number +of input images. +.le +.ls database +The name of the text file containing the coordinate transformation (generally +the database file produced by GEOMAP). +If database is the null string then GEOTRAN will perform a linear +transformation based the values of xin, yin, xout, yout, xshift, yshift, +xmag, ymag, xrotation and yrotation. If all these parameters have their +defaults values the transformation is a null transformation. If the geometric +transformation is linear xin, yin, xout, yout, xshift, yshift, xmag, ymag, +xrotation and yrotation can be used to override the values in the database +file. +.le +.ls transforms +The list of record name(s) in the file \fIdatabase\fR containing the +desired transformations. +This record name is usually the name of the text file input to geomap +listing the reference and input coordinates of the control points. +The number of records must be 1 or equal to the number of input images. +The record names may be listed in a text file 1 record per line. +The transforms parameter is only +requested if database is not equal to the null string. +.le +.ls geometry = "geometric" +The type of geometric transformation. The geometry parameter is +only requested if database is not equal to the null string. The options are: +.ls linear +Perform only the linear part of the geometric transformation. +.le +.ls geometric +Compute both the linear and distortion portions of the geometric correction. +.le +.le +.ls xmin = INDEF, xmax = INDEF, ymin = INDEF, ymax = INDEF +The minimum and maximum x and y reference values of the output image. +If a database file has been defined xmin, xmax, ymin and ymax +efault to the minimum and maximum values set by +GEOMAP and may be less than but may not exceed those values. +.le +.ls xscale = 1.0, yscale = 1.0 +The output picture x and y scales in units of +x and y reference units per output pixel, +e.g arcsec / pixel or Angstroms / pixel if the reference coordinates +are arcsec or Angstroms. If the reference coordinates are in pixels +then xscale and yscale should be 1.0 to preserve the scale of the reference +image. +If xscale and yscale are undefined (INDEF), xscale and yscale default to the +range of the reference coordinates over the range in pixels. +Xscale and yscale override the values of ncols and nlines. +.le +.ls ncols = INDEF, nlines = INDEF +The number of columns and lines in the output image. Ncols and nlines default +to the size of the input image. If xscale or yscale are defined ncols or nlines +are overridden. +.le +.ls xsample = 1.0, ysample = 1.0 +The coordinate surface subsampling factor. The coordinate surfaces are +evaluated at every xsample-th pixel in x and every ysample-th pixel in y. +Transformed coordinates at intermediate pixel values are determined by +bilinear interpolation in the coordinate surfaces. If the coordinate +surface is of high order setting these numbers to some reasonably high +value is strongly recommended. +.le +.ls interpolant = "linear" +The interpolant used for rebinning the image. +The choices are the following. +.ls nearest +Nearest neighbor. +.le +.ls linear +Bilinear interpolation in x and y. +.le +.ls poly3 +Third order polynomial in x and y. +.le +.ls poly5 +Fifth order polynomial in x and y. +.le +.ls spline3 +Bicubic spline. +.le +.ls sinc +2D sinc interpolation. Users can specify the sinc interpolant width by +appending a width value to the interpolant string, e.g. sinc51 specifies +a 51 by 51 pixel wide sinc interpolant. The sinc width will be rounded up to +the nearest odd number. The default sinc width is 31 by 31. +.le +.ls lsinc +Look-up table sinc interpolation. Users can specify the look-up table sinc +interpolant width by appending a width value to the interpolant string, e.g. +lsinc51 specifies a 51 by 51 pixel wide look-up table sinc interpolant. The user +supplied sinc width will be rounded up to the nearest odd number. The default +sinc width is 31 by 31 pixels. Users can specify the resolution of the lookup +table sinc by appending the look-up table size in square brackets to the +interpolant string, e.g. lsinc51[20] specifies a 20 by 20 element sinc +look-up table interpolant with a pixel resolution of 0.05 pixels in x and y. +The default look-up table size and resolution are 20 by 20 and 0.05 pixels +in x and y respectively. +.le +.ls drizzle +2D drizzle resampling. Users can specify the drizzle pixel fraction in x and y +by appending a value between 0.0 and 1.0 in square brackets to the +interpolant string, e.g. drizzle[0.5]. The default value is 1.0. +The value 0.0 is increased internally to 0.001. Drizzle resampling +with a pixel fraction of 1.0 in x and y is equivalent to fractional pixel +rotated block summing (fluxconserve = yes) or averaging (flux_conserve = no) if +xmag and ymag are > 1.0. +.le +.le +.ls boundary = "nearest" +The choices are: +.ls nearest +Use the value of the nearest boundary pixel. +.le +.ls constant +Use a user supplied constant value. +.le +.ls reflect +Generate a value by reflecting about the boundary of the image. +.le +.ls wrap +Generate a value by wrapping around to the opposite side of the image. +.le +.le +.ls constant = 0.0 +The value of the constant for boundary extension. +.le +.ls fluxconserve = yes +Preserve the total image flux. The output pixel values are multiplied by +the Jacobian of the coordinate transformation. +.le +.ls xin = INDEF, yin = INDEF +The x and y coordinates in pixel units in the input image which will map to +xout, yout in the output image. If the database file is undefined these +numbers default to the center of the input image. +.le +.ls xout = INDEF, yout = INDEF +The x and y reference coordinates in the output image which correspond +to xin, yin in the input image. If the database file is undefined, xout and +yout default to the center of the output image reference coordinates. +.le +.ls xshift = INDEF, yshift = INDEF +The shift of the input origin in pixels. If the database file is undefined +then xshift and yshift determine the shift of xin, yin. +.le +.ls xmag = INDEF, ymag = INDEF +The scale factors of the coordinate transformation in units of input pixels +per reference coordinate unit. If database is undefined xmag and ymag +default to 1.0; otherwise xmag and ymag default to the values found +by GEOMAP. If the database file is not null then xmag and ymag override +the values found by GEOMAP. +.le +.ls xrotation = INDEF, yrotation = INDEF +The rotation angles in degrees of the coordinate transformation. +Positive angles are measured counter-clockwise with respect to the x axis. +If database +is undefined then xrotation and yrotation default to 0.0; otherwise +xrotation and yrotation default to the values found by GEOMAP. +If database is not NULL then xrotation and yrotation override the values +found by GEOMAP. +.le +.ls nxblock = 512, nyblock = 512 +If the size of the output image is less than nxblock by nyblock then +the entire image is transformed at once. Otherwise the output image +is computed in blocks of nxblock by nxblock pixels. +.le +.ls verbose = yes +Print messages about the progress of the task ? +.le +.ih +DESCRIPTION + +GEOTRAN corrects an image for geometric distortion using the coordinate +transformation determined by GEOMAP. The transformation is stored as the +coefficients of a polynomial surface in record \fItransforms\fR, +in the text file \fIdatabase\fR. +The coordinate surface is sampled at every \fIxsample\fR and \fIysample\fR +pixel in x and y. +The transformed coordinates at intermediate pixel values are +determined by bilinear interpolation in the coordinate surface. If +\fIxsample\fR and \fIysample\fR = 1, the coordinate +surface is evaluated at every pixel. Use of \fIxsample\fR and \fIysample\fR +are strongly recommended for large images and high order coordinate +surfaces in order to reduce the execution time. + +\fIXmin\fR, \fIxmax\fR, \fIymin\fR and \fIymax\fR define the range of +reference coordinates represented in the output picture. These numbers +default to the minimum and maximum x and y reference values used by GEOMAP, +and may not exceed those values. +The scale and size of the output picture is determined as follows. + +.nf + ncols = ncols (inimage) + if (xscale == INDEF) + xscale = (xmax - xmin ) / (ncols - 1) + else + ncols = (xmax - xmin) / xscale + 1 + + nlines = nlines (inimage) + if (yscale == INDEF) + yscale = (ymax - ymin ) / (nlines - 1) + else + nlines = (ymax - ymin) / yscale + 1 +.fi + +The output image gray levels are determined by interpolating in the input +image at the positions of the transformed output pixels. If the +\fIfluxconserve\fR switch is set the output pixel values are multiplied by +the Jacobian of the transformation. +GEOTRAN uses the routines in the 2-D interpolation package. + +The linear portion of the transformation may be altered after the fact +by setting some or all of the parameters \fIxin\fR, \fIyin\fR, \fIxout\fR, +\fIyout\fR, \fIxshift\fR, \fIyshift\fR, \fIxmag\fR, \fIymag\fR, \fIxrotation\fR, +\fIyrotation\fR. +Xin, yin, xshift, yshift, xout and yout can be used to redefine the shift. +Xmag, and ymag can be used to reset the x and y scale of the transformation. +Xrotation and yrotation can be used to reset the orientation of the +transformation. + +The output image is computed in \fInxblock\fR by \fInyblock\fR pixel sections. +If possible users should set these numbers to values larger than the dimensions +of the output image to minimize the number of disk reads and writes required +to compute the output image. If this is not feasible and the image rotation is +small, users should set nxblock to be greater than the number of columns in +the output image, and nyblock to be as large as machine memory will permit. + +If the CL environment variable \fInomwcs\fR is "no" then the world +coordinate system of the input image will be modified in the output image +to reflect the effects of the \fIlinear\fR portion of the geometric +transformation operation. +Support does not yet exist in the IRAF world coordinate system interface +for the higher order distortion corrections that GEOTRAN is capable of +performing. + +.ih +TIMINGS +It requires approximately 70 and 290 cpu seconds to correct a 512 by 512 +square image for geometric distortion using a low order coordinate surface +and bilinear and biquintic interpolation respectively (Vax 11/750 fpa). + +.ih +EXAMPLES + +1. Register two images by transforming the coordinate system of the input +image to the coordinate system of the reference image. The size of the +reference image is 512 by 512. The output image scale will be 1.0 and +its size will be determined by the xmin, xmax, ymin, ymax parameters set +in the task GEOMAP. The file "database" containing the record "m51.coo" +was produced by GEOMAP. + +.nf + cl> geomap m51.coo database 1.0 512.0 1.0 512.0 + cl> geotran m51 m51.tran database m51.coo +.fi + +2. Repeat the above command but set the output image scale to 2.0 reference +images pixels per output image pixel. + +.nf + cl> geomap m51.coo database 1.0 512.0 1.0 512.0 + cl> geotran m51 m51.tran database m51.coo xscale=2.0 yscale=2.0 +.fi + +3. Repeat the previous command using an output scale of +2 reference units per pixel and bicubic spline interpolation with no +flux correction. + +.nf + cl> geomap m51.coo database 1.0 512.0 1.0 512.0 + cl> geotran m51 m51.tran database m51.coo xscale=2. yscale=2. \ + >>> inter=spline3 flux- +.fi + +4. Register a list of 512 by 512 pixel square images using the set of +transforms computed by GEOMAP. The input images, output images, and coordinate +lists / transforms are listed in the files inlist, outlist and reclist +respectively. + +.nf + cl> geomap @reclist database 1. 512. 1. 512. + cl> geotran @inlist @outlist database @reclist +.fi + +5. Mosaic 3 512 square images into a larger 512 by 1536 square images after +applying a shift to each input image. + +.nf + cl> geotran image1 outimage[1:512,1:512] "" ncols=512 nlines=1536 \ + xshift=5.0 yshift=5.0 + cl> geotran image2 outimage[1:512,513:1024] "" xshift=10.0 yshift=10.0 + cl> geotran image3 outimage[1:512,1025:1536] "" xshift=15.0 yshift=15.0 +.fi + +.ih +BUGS +Support does not yet exist in the IRAF world coordinate system interface +for the higher order distortion corrections that GEOTRAN is capable of +performing. + +.ih +SEE ALSO +imshift, magnify, rotate, imlintran, geomap, geoxytran, gregister +.endhelp |