; OGEOM ;--------------------------------------------------------------- ;! Simple image rotation, scaling, and translation ;# Task IMAGE-UTIL OOP ;----------------------------------------------------------------------- ;; Copyright (C) 1996, 2005, 2010 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- OGEOM LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC OGEOM: Interpolate an image to the geometry of another. Input image INNAME Image name (name) INCLASS Image name (class) INSEQ 0.0 9999.0 Image name (seq. #) INDISK 0.0 9.0 Image disk drive # Output image OUTNAME Image name (name) OUTCLASS Image name (class) OUTSEQ -1.0 9999.0 Image name (seq. #) OUTDISK 0.0 9.0 Image disk drive # BLC 0.0 4096.0 Bottom left corner of image 0=>entire image TRC 0.0 4096.0 Top right corner of image 0=>entire image IMSIZE 0.0 4096.0 Output image size in pixels REWEIGHT 0.0 4.0 (1) Interpolation halfwidth (2) Minimum fraction of good pixels required (0->1/3) APARM (1)=Delta X in pixels (2)=Delta Y in pixels (3)=rotate(deg) (4)=scale, (5)=diff.scale (6)=shift X coordinates : ??? (7)=shift Y coordinates : ??? ---------------------------------------------------------------- OGEOM Type: Task Use: OGEOM does an interpolation of an image to a rotated, shifted, and scaled output image. It is assumed that the image geometry is linear for these purposes. Use OHGEO for larger fields. Interpolation is done only in the first 2 dimensions. Unlike LGEOM, OGEOM will interpolate over blanked pixels so that it can fill in small blanked regions and handle edges without having to discard image area. NOTE: the input subimage is read into dynamically allocated memory. Very large input arrays may cause swapping on your computer. This task does a straightforward interpolation from the input to the output image grid. This process cannot be completely accurate if, for example, one shifts and scales an image and then reverses that process. Greater accuracy will be achieved on images with more points per beam and with larger support sizes for the interpolator. Adverbs: INNAME......The input image name. Standard defaults. INCLASS.....The input image class. Standard defaults. INSEQ.......The input image sequence number. 0 => high INDISK......The input image disk drive no. 0 => any OUTNAME.....The output image name. blank => Standard defaults based on INNAME. OUTCLASS....The output image class. Standard behavior. OUTSEQ......The output image seq. no., 0=> highest unique If >0; image will be created if new, overwritten if image name exists. OUTDISK.....Output disk drive no., 0=> highest with space BLC.........The bottom left-hand pixel of the input image which becomes the bottom left corner of the input subimage. The value (0,0) means (1,1). TRC.........The top right-hand pixel of the input image which becomes the top right corner of the subimage. The value (0,0) means take the top right hand corner of the image. IMSIZE......Output image size in pixels [1=columns, 2=rows]. Default is the input image size. If the output image size is the same as the input size in both axes, then the reference pixel is not changed other than by the addition of APARM(1) and APARM(2). REWEIGHT....Interpolation kernal parameters: (1) Half width of the interpolating kernel (1 - 4). Default = 1 Larger support sizes should produce more accurate results at the cost of increased computation. (2) Minimum fraction of pixels in interpolation kernal area required for non-blanked output. <= 0 or >= 1 => 0.333 APARM.......Transformation parameters: 1 & 2 = shift of coordinate reference point, expressed in output pixels, for x & y relative to the center of the subimage. Positive moves objects to the right and up relative to center pixel. 3 = rotation in degrees (positive moves objects counterclockwise relative to the image center as they map from input image to output image). 4 = scale factor (greater than one moves objects outward from the image center as they map from input to output). This is applied wrt the image center defined as Naxis(1)/2, Naxis(2)/2 + 1. 5 = 'differential scale'; this is an extra scale factor applied to the y-axis AFTER the main transformation has been done. This is useful to make spiral galaxies appear face-on. Also, if it is negated the result is a mirror-reflection in the y-axis. 6 & 7 = Coordinate shift in X and Y in arc seconds. The measured right ascension and declination of objects will change. Positive increases the RA and Dec. if the image has the normal orientation (RA increasing to the left, Dec. increasing upwards, no rotation). Note that this option corrects the shift for the cos of the latitude which only works correctly when there are no rotations. THIS OPTION DESTROYS THE COORDINATES YOU WENT TO A LOT OF TROUBLE TO MEASURE. Use it only in dire straights. ----------------------------------------------------------------