; TVSTAT ;--------------------------------------------------------------- ;! Find the mean and RMS in a blotch region on the TV ;# VERB TV INTERACTIVE ;----------------------------------------------------------------------- ;; Copyright (C) 1995, 2003 ;; 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 ;----------------------------------------------------------------------- TVSTAT LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC TVSTAT: Verb to find the mean, rms and extrema in a TV subimage DOINVERS -1.0 1.0 >0 find stats outside blotch <=0 find stats inside blotch Main input is the image on the TV and cursor inputs. @ Output adverbs: PIXAVG @ Mean pixel value PIXSTD @ RMS about mean pixel value PIXVAL @ Peak pixel value PIXXY @ Coordinates of peak (pixels) PIX2VAL @ Minimum pixel value PIX2XY @ Coords of minimum (pixels) ---------------------------------------------------------------- TVSTAT Type: Verb Use: TVSTAT will read a portion of an image and print the mean and rms brightnesses found. It also prints the locations and values of the max/min brightnesses in that portion. It returns these results in adverbs. TVSTAT differs from IMSTAT in 2 ways: it uses the current TV image rather than an image specified by adverbs and it determines the values over irregular regions ("blotch" areas) marked by the user with the TV cursor. (See EXPLAIN TVSTAT for details.) Adverbs (input): DOINVERS....If true (>0.), find statistics over full image as displayed on the TV except for the blotch regions. If false (<= 0.), find statistics inside the blotch regions. Adverbs (output): PIXAVG......Mean pixel value found in subimage in the same units as the image (e.g. Jy/beam). PIXSTD......RMS in the pixel values about the mean in the subimage in the same units as the image. PIXVAL......Peak pixel value in the subimage. PIXXY.......Pixel coordinates of the pixel having the largest value within the subimage. PIX2VAL.....Minimum pixel value in the subimage. PIX2XY......Pixel coordinates of the pixel having the smallest value within the subimage. ---------------------------------------------------------------- TVSTAT PURPOSE TVSTAT is intended to let users determine image statistics over irregular regions of an image. It returns the mean, rms, and maximum brightnesses and the pixel position of the maximum in adverbs intended for use by RUN files and other automatic procedures. It does, however, require user interaction via the TV. For batch and other truely automatic processes the verb IMSTAT should be used instead. The TV cursor is used to set the vertices of one or more polygonal "blotch" regions and the results are determined only for those pixels which fall within or without (see DOINVERS below) the blotch regions. The routine begins by asking for the vertices of polygon 1. Move the TV cursor to the desired spot and press Button A. Then move it to the next vertex and again press Button A. Continue this process moving strictly in a clockwise or a counter-clockwise direction. When the last vertex of the polygon is reached, press one of Buttons B, C, or D to finish the current polygon. (The program will take care of drawing the line from the last vertex to the initial one.) Button B means that you wish to set another, independent polygon; Button C means that you wish to correct one or more previously set vertices; and Button D means that you are done setting the blotch areas. If you go into "correction" mode (via Button C at the end of a polygon), then move the cursor over the vertex that you wish to correct and press either button A or B to indicate your selection. Further movement of the cursor will cause the vertex position to shift with it. Press any button to set the new vertex position. Button A or B mean that you wish to correct another vertex. In either step of the correction, Button C means that you wish to go on to a new, independent polygon and Button D means that you wish to quit setting polygons. After the polygons are set (Button D pressed), the routine fills in the polygons obscuring the blotch regions. After some further delay, it prints the results (at message level 5) and puts the answers in the PIXAVG, PIXSTD, PIXVAL, PIXXY, PIX2VAL, and PIX2XY adverbs. The sequence in which the vertices are set is important. One must maintain either a clockwise or a counter clockwise direction. However there is a trick. In the diagram below, the asterisks (*) represent a source and we wish to determine the rms over the entire area not including the source. The numbers are the sequence of vertices: 2 3 6 * ** 7 **** "" ++ ** * 9 1 12 where "" represents vertices 5 and 10 and ++ represents vertices 4 and 11 on top of each other. The basic clockwise motion includes the inner area, while the small counter-clockwise motion excludes the innermost area. Be very careful to set all vertices within the image. An easier way to carry out this function is to set DOINVERS to true (1.0). Then the statistics are determined for all map points visible on the TV (ignoring zoom) except for those inside the blotch region(s). The description above assumes that DOINVERS is false (<= 0.0). Be careful with this adverb --- PRTPL uses it for another purpose and one seldom wants it true for that purpose (a mostly black image). ----------------------------------------------------------------