; AHIST ;--------------------------------------------------------------- ;! Task to convert image intensities by adaptive histogram ;# Task Imaging Analysis ;----------------------------------------------------------------------- ;; Copyright (C) 1995 ;; 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 ;----------------------------------------------------------------------- ;--------------------------------------------------------------- AHIST LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC AHIST Translates image intensities by windowed histogram INNAME Input image name (name) INCLASS Input image name (class) INSEQ 0.0 9999.0 Input image name (seq. #) INDISK 0.0 9.0 Input image disk unit # OUTNAME Output image name (name) OUTCLASS Output image name (class) OUTSEQ -1.0 9999.0 Output image name (seq. #) OUTDISK 0.0 9.0 Output image disk unit #. BLC Bottom left corner of input TRC Top right corner of input XINC 0.0 29.0 Window size in X YINC 0.0 29.0 Window size in Y PIXRANGE Pixel range included in the histograms. ---------------------------------------------------------------- AHIST Task: This task converts the image intensities by performing a histogram equalization over a window XINC by YINC pixels centered on each output pixel. This operation enhances the contrast in regions of low contrast and reduces the differences between very bright and very weak intensities. HISEQ performs this operation over the full image (cube) while AHIST uses a 2-dimensional window about each pixel. Adverbs: INNAME.....Input image name (name). Standard defaults. INCLASS....Input image name (class). Standard defaults. INSEQ......Input image name (seq. #). 0 => highest. INDISK.....Disk drive # of input image. 0 => any. OUTNAME....Output image name (name). Standard defaults. OUTCLASS...Output image name (class). Standard defaults. OUTSEQ.....Output image name (seq. #). 0 => highest unique. OUTDISK....Disk drive # of output image. 0 => highest disk number with sufficient space. BLC........Bottom right corner in input image of desired subimage. Default is entire image. TRC........Top right corner in input image of desired subimage. Default is entire image. XINC.......Window size in X pixels - should be odd and at least 5. Limit is 29, 0 => 11. XINC/2 pixels on the left and right edges will be blanked. YINC.......Window size in Y pixels - should be odd and at least 5. Limit is 29, 0 => 11. YINC/2 rows on the top and bottom will be blanked. PIXRANGE...Pixels outside this intensity range are not included in the hsitograms and are set to -0.001 and 1.001 respectively. PIXRANGE(2) <= PIXRANGE(1) tells the task to use the full image intensity range. It is often best to specify PIXRANGE(1) to be just above the background noise level. Otherwise the algorithm greatly expands this background emphasizing the noise. ----------------------------------------------------------------