Image ID Question

Question about Image Identification

 Scott and the APL engineers have, by necessity, established an interim image ID scheme, summarized below. However, they have also (at the prodding of the Science Data Center activity) been thinking about image IDs for the mission. Since this is something we're going to have to use and live with for quite a while, I belive we as a team should give this some thought.

The image ID must have a few pecularities mandated by the Planetary Data System (e.g., eight alphanumeric characters followed by a three charcter suffix). Within these limitations, the scheme proposed by APL for "in-flight" (and for that matter, calibration data--with the recent data to be renumbered once the scheme is settled) is:

YDOYNODF.TYP
where

Y
Year of mission: 1994 = 1, 1995 = 2, 1996 = 3, 1997 = 4, 1998 = 5, 1999 = 6, 2000 = 7, 2001 = 8
DOY
Day of Year: 1 January = 001, 1 February = 032, etc.
NOD
Number of image on Day: the first image taken on a given DOY would be 001, the second 002, etc.
F
Filter: each filter would be indicated by its position number in the filter wheel
TYP
Type (format) of image: the Project originally was considering FITS, but I believe we've convinced them to bite the bullet and go directly to PDS. Thus TYP would always be PDS.
Example: The first image taken on 17 February 1999 would be 604700011.PDS if taken through the filter in wheel position 1.

I have a problem remembering strings of numbers, and was a bit concerned that this scheme did not increment regularly (its a code, not a number), i.e., the image immediately following the example above could be 604700028.PDS, and the one immediately preceding it could be 604600933.PDS. Thus, the "numbering scheme" would have a gaps of 17 and 99078 between successive frames.

I have an easier time remembering mixes of alphabetic and numeric characters, so I gave this a little thought, and concluded that a "time-based" scheme might be less desirable than a mission operations-based scheme (something like the difference between PICNO and FSC number). I thought up the following:

MPIMNOFL.TYP
where

MP
Mission Phase: Calibration = CA (or CL), Cruise = CR, Earth/Moon = EM, etc. Mapping cycles could be numbered sequentially, or the number could represent the orbit distance to Eros.
IMNO
Image Number during mission phase: This is an incremental counter such that sequential images have sequential IDs.
FL
Filter: this is a two letter abbreviation for the filter, e.g., CL = clear, BL = 450 nm, GR = 550 nm, RD = 760 nm, I1 = 900 nm, I2 = 950 nm, I3 = 1000 nm, I4 = 1050, or some other scheme.
TYP
Type (format) of image: Same as above, (i.e. TYP would always be PDS).
Example: Using the example from above, the first image on 17 February 1999 might be IN2453CL.PDS (Insertion orbit = 1000 km distance), with the immediately preceding image IN2452I4.PDS and the following image IN2454GN.PDS.

I'm not particularly advocating one scheme over another; rather, I'm soliciting thought on the subject by the Team, with the intent of discussing it at the next team meeting. I believe the Project will welcome appropriate alternative schemes, provided we make our input in a timely fashion.