MVT -- TIROS/NOAA Tape to Video Transfer
Transfers image data from an AES TIROS/NOAA (AVHRR) magnetic tape to
the video display.
PARAMETERS
MVT is controlled by the following global parameters:
Name Prompt Count Type
MTIC Mag Tape Input Channel List 1-5 Int
VDOC Video Output Channel List 1-5 Int
MTIW Mag Tape Input Window 0-4 Int
VDOW Video Output Window 0-4 Int
ROTA Rotate Image: ON/OFF 2-3 Char
STARTFIL Start File on Tape 1 Int
MTIC
The PACE parameter MTIC represents a list of image channels that
reside on the input magnetic tape:
EASI>MTIC=i,j,...,m | integers, 1-5
- Only the channels specified in MTIC are used by MVT.
- Up to 5 channels can be handled.
- Ranges of channels can be specified with negative values. For
example: {1,-3,5} is internally expanded to {1,2,3,5}.
VDOC
VDOC represents a list of output image channels to receive imagery
for the video display:
EASI>VDOC=i,j,...,p | integers, 1-?
- The number of channels required in this list varies with the
installation hardware. Requesting the status of MVT is the
easiest way of finding the number of channels needed for VDOC.
- Up to 5 channels can be handled.
- Ranges of channels can be specified with negative values. For
example: {1,-3,5} is internally expanded to {1,2,3,5}.
MTIW
MTIW specifies a rectangular subset of an image on magnetic tape to
be used for input to the MVT task:
EASI>MTIW=Xoffset,Yoffset,Xsize,Ysize
EASI>MTIW= | defaults to entire image
- The offset + size must not exceed the image size.
VDOW
VDOW specifies a rectangular subset of the image channel data to be
received on the video display:
EASI>VDOW=Xoffset,Yoffset,Xsize,Ysize
EASI>VDOW= | defaults to entire image
- The offset + size must not exceed the image size.
ROTA
If ROTA="ON", image is rotated 180 degrees.
EASI>ROTA="OFF"
STARTFIL
Specifies the start file number on tape from which to start reading
header and image data. If STARTFIL is greater than one, the program
rewinds the tape and advances to the specified file. STARTFIL must
be set to the file number required by MSH program to print tape
header report.
EASI>STARTFIL=1 | read first file on tape
EASI>STARTFIL=n | read nth file on tape
DETAILS
MVT transfers image data from any set of bands on TIROS or NOAA tape
(MTIC) to any set of image planes on a video display (VDOC).
Any arbitrary rectangular window on tape (MTIW) can be transferred
to any arbitrary rectangular window on the display (VDOW). Shrinking
and/or zooming is automatically performed. By default, the whole
tape image is transferred, filling the entire display.
Any file (image) on tape (STARTFIL) can be specified. MVT will will
rewind and then advance to the selected file before transferring.
The image can be rotated (ROTA) a full 180 degrees before being
shown on the display, if desired. This turns the image upside- down.
By default, rotation is OFF.
More information on TIROS mag tape format can be found in the
documentation for program IMT.
A TAPE MUST BE MOUNTED ON THE TAPE DRIVE BEFORE MVT CAN BE RUN.
CLEANING THE TAPE HEADS IS RECOMMENDED TO MINIMIZE THE CHANCE OF
TAPE READ ERRORS.
EXAMPLE
Object: Transfer 3-band image from tape to display, then perform
default enhancement (square root contrast stretch).
EASI>RUN DCP "LZ" | initialize lookup tables
EASI>RUN DCP "ID3,2,1" | colour mapping - RGB
EASI>LET MTIC=1,2,3
EASI>LET VDOC=1,2,3
EASI>LET MTIW= | read entire mag tape image
EASI>LET VDOW= | use the entire video window
EASI>LET ROTA="OFF"
EASI>LET STARTFIL=1
EASI>RUN MVT
EASI>RUN DCP "LC" | default enhancement
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