As mentioned, the systems that need this most don't have even frontlit displays, so a colorimeter would not work on them. There's also the question of what the correct contrast setting should be on the analog adjustment wheels these systems had. Ideally you'd want to capture multiple contrast settings, and then try and devise an underlying adjustment algorithm from all the data sets to approximate the full analog range of positions for it.

The wikipedia page on Walsh functions says:

>They are also used in passive LCD panels as X and Y binary driving waveforms where the autocorrelation between X and Y can be made minimal for pixels that are off.

Not sure how applicable that is on which of the systems you are considering. Sorry for the rabbit hole ;)