GETDIGITS

Name

getdigits

Purpose (one Line Only)

Decode a single image with an IOTA-VTI time code

Description

Scan image for IOTA-VTI time code information and decode into a
a machine-readable form. This can handle IOTA-VTI output only and
only in either 720x480 or 640x480 pixel formats.

Calling Sequence

getdigits,image,odd,even,otime,onum,etime,enum

Inputs

image - 3 x N x M byte image to decode

Optional Input Parameters

Keyword Input Parameters

DEBUG - Flag, if set will generate copious output and graphics.

Outputs

odd - String array with the one character decoded from each cell
from the odd field.
even - String array with the one character decoded from each cell
from the even field.
otime - String with the odd field time, HH:MM:SS.ssss, empty if decode
was not successful.
onum - Long integer with the odd field number
etime - String with the even field time, HH:MM:SS.ssss, empty if decode
was not successful.
enum - Long integer with the even field number

Keyword Output Parameters

Common Blocks

Side Effects

Restrictions

Image must be 3x720x480 or 3x640x480. Only plane 0 is read.
Requires access to two files:
digits_640_480.fits and digits_720_480.fits
These files must be somewhere in your IDL_PATH but usual reside in the
same directory as my IDL library.

Procedure

A hueristic procedure is used to determine the row location of the
time code data. The x location of the cells where characters are
found is hard coded. A row-summed version of the image shows a
characteristic three-peak shape. The middle peak is used as the center
of the digits written to the video. The position is required to be
in a small range near the bottom of the image. The results are not
validated in any way. The return is an array of characters and if nothing
was found, the character is a empty string.
The time codes are read from the even and odd fields of the images as well
as the field counter.

Modification History

2016/03/08, Written by Marc W. Buie, Southwest Research Institute
2016/03/25, MWB, added DEBUG, XOFF, and YOFF keywords
2016/09/01, MWB, added support for 2-d images and improved reliability