IDLE is a toolbox for modelling simultaneous intensity and position changes.

In sound this occurs when there are simultaneous changes in pitch and timbre, e.g. when a person changes from singing “A” to “O” while at the same time changing from the note C to the note D.

In light this occurs when light from remote galaxies indicates both the presence of various substances (the spectre) and a distance (through red shift, i.e. moving the spectre).

In video this occurs when an object moves and at the same time changes appearance.

In many other measurement systems there are similar effects.

The basic challenge is:
How can you model the appearance of something before you know exactly where it is, and how can you model where it is before you know the exact appearance?

IDLE gives an answer to this in cases where there are sufficiently large amounts of data containing gradual change.

The name IDLE stems from the formula:

I = D(L) + e

An Image (what we observe) is the result of Displacing (moving) an instantiation of a Localized model according to a motion model, plus an error term e for the part of the observation that cannot be explained by D(L).