AIPS HELP file for TVDIC in 31DEC24
As of Tue Apr 23 6:49:54 2024
TVDIC: Task to copy a TV image to a Dicomed film recorder.
INPUTS
OUTPRINT
Name of the output file.
blank -> place in film
recorder queue.
APARM Control parameters:
(1) Film size
0 -> 35mm
1 -> 2"x2"
2 -> 4"x5"
(2) File type
0 -> colour positive
1 -> colour negative
2 -> B/W negative
COPIES 0 99 Number of copies to print.
0 -> 1
FLMCOMM
Comment to be placed in the
Dicomed log file.
HELP SECTION
TVDIC
Type: task (NRAO specific).
Use: TVDIC reads the current contents of an AIPS TV screen and
copies them to an Dicomed image file. The resulting image
file is either automatically spooled to the film recorder
or saved under a name chosen by the user.
The Dicomed image file format is used only at NRAO
Charlottesville and at the AOC.
Adverbs:
OUTPRINT...The name of the image file. If this is left blank
then the image file is automatically placed in the
film recorder queue. If a name is provided the
image file will be saved under this name and will
not be placed in the Dicomed queue.
APARM......Options.
(1) The film size.
0 -> 35mm
1 -> 2"x2" (on 4"x5" Polaroid)
2 -> 4"x5" (on 4"x5" Polaroid)
(2) The film type.
0 -> colour positive (slide or Polaroid)
1 -> colour negative
2 -> B/W negative
COPIES.....Number of copies to produce.
0 -> 1
FLMCOMM...Comment to go into the Dicomed log file.
EXPLAIN SECTION
TVDIC: Task which copies the contents of an AIPS TV screen to
a Dicomed image file.
DOCUMENTOR: Chris Flatters, NRAO
PURPOSE
TVDIC is used to make a hard copy of the contents of an AIPS
TV display. The contents of all enabled grey-scale planes
and all enabled graphics planes are read from the TV device and
written to a Dicomed image file. This file is either placed in a
queue of images to be exposed on a Dicomed film recorder or saved
under a name specified by the user to be queued by the user.
The Dicomed image file format is NRAO-specific and is only
used at the AOC and at NRAO Charlottesville.
TVDIC replaces the highly non-standard task TVFLM that was
previously used at the AOC. Unlike TVFLM, TVDIC will
work with any AIPS TV.
LIMITATIONS
TVDIC will not provide a perfect reproduction of the TV display.
1) Information regarding the zoom and scroll state of the TV
is not available to TVFLM so that images will be reproduced
as if they had unit zoom and zero scroll.
HINT: use the TBLC, TTRC, TXINC and TYINC adverbs to set
position of an image on the screen and to expand
small images rather than using hardware zoom and
scroll if you want to make a hard copy.
2) AIPS TV images are gamma corrected (gamma correction takes
account of the fact that colour intensity is not linearly
related to the voltage fed to each of the colour guns).
Dicomed images are not gamma corrected. This may lead to
inaccurate colour reproduction. Gamma correction of
Dicomed images is impractical since the correction depends
on the film stock and the exposure time.
3) Images on black and white film use only the signal from the
red channel and assume that overlay planes 1 to 3 are
pure white and overlay plane 4 is black.
HINT: Do not make black and white hard-copy of pseudocolour
images.
DICOMED IMAGE FILE FORMAT
The Dicomed image format was designed by Arnold Rots. A Dicomed
image file has three sections. In order these are the header,
the LUT data (optional) and the image data.
Header
The header consists of 8 64-character ASCII "card images" (a
total of 512 bytes). Each card image contains a number of
keyword and value pairs and is terminated with a newline
(ASCII LF). The header layout is as follows, where Xs denote
variable fields.
000000000111111111122222222223333333333444444444455555555556666
123456789012345678901234567890123456789012345678901234567890123
Filename: XXXXXXXXXXXXXXXXXX Origin: XXXXXXXX
Date: XXXXXXXXX Time: XXXXXXXX Userno: XXXX
Filmsize: XXXX Filmtype: XXXXXXX Copies: XXX
Bits/Pixel: XX Columns: XXXX Rows: XXXX
LUTs/Pixelbyte: X Bits/LUTelement: XX OFMelements: XXXX
LUTpointer: XXXXXX OFMpointer: XXXXX Datapointer: XXXXX
Usercomments: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Recorded: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Note that values are left justified within the fields and
padded with blanks.
The header fields are filled in as follows.
Filename........The name under which the image file will be
queued. This has the format NNNN_DDD_HHMMSS_V1
where NNNN is the (decimal) AIPS user number,
DDD is the day of the year on which the file
was created and HHMMSS is the time at which
the file was created.
Example: 0115_113_123554_V1
Origin..........The hostname of the computer on which the file
was created.
Date............The file creation date in the format DD-MMM-YY
where DD is the day, MMM is a 3-letter
abbreviation for the month (mixed case) and YY
is the last two digits of the year.
Example: 22-Apr-92
Time............The file creation time in the format HH:MM:SS.
Example: 12:35:54
Userno..........AIPS usernumber.
Filmsize........"35mm", "2x2" or "4x5".
Filmtype........"ColPos", "ColNeg", or "B/W"
Copies..........Number of copies to make.
Bits/Pixel......8 for monochrome film; 24 for colour film.
Columns.........Width of image in pixels.
Rows............Height of image in pixels.
LUTs/Pixelbyte..Number of LUTs per channel.
Bits/LUTelement.Number of bits in an LUT output value.
OFMelements.....Number of elements in an LUT.
LUTpointer......Address of the first byte of LUT data or zero
if there is no LUT. Uses the UNIX convention
where the first byte in the file has address 0.
OFMpointer......Address of the first byte of OFM data or zero
if there no OFMs. Uses the UNIX convention
where the first byte in the file has address 0.
Datapointer.....Address of the first byte of image data. Uses
the UNIX convention where the first byte in
the file has address zero.
Comment.........Comment to be written into Dicomed log.
Recorded........Unused.
LUT and OFM data
TVDIC does not use the Dicomed image file look up tables.
Image Data
Each pixel in a monochrome image is represented by a single byte
value. Each pixel in a colour image is represented by three
byte values giving its red, green and blue intensities in that
order. Pixels are written in row-wise order starting from the
top, leftmost pixel and ending with the bottom, rightmost pixel.
USING TVDIC AS A PARAFORM
The Dicomed image file specific code is isolated in 3 Z-routines.
ZDICOP opens a Dicomed image file and fills in the header,
ZDICIO writes an image row to file and ZDICCL closes the file
and saves it or places it in the Dicomed queue. Other hard-copy
devices may be supported by replacing these Z-routines. You
should also change the name of the task of course.
Other desirable changes are:
1) change the argument list for the ZxxxOP routine: ZDICOP
has a long argument list most of which is only needed
to fill in the Dicomed image file header.
2) make sure that rows are written to the image file in the
order required by the file format for efficiency.
3) add any extra adverbs that may be needed.