Superimposition

Some reel-to-reel tape recorders of the mid 20th century provided crude superimposition facilities that were implemented by killing the high-frequency AC feed to the erase head while recording as normal via the read-write head.

Superimposition of two-dimensional images containing correlated periodic grid structures may produce moiré patterns.

When superimposing two identical layers comprising randomly spaced parallel lines, at a small angle or with a small scaling difference random line moiré patterns,[1] namely line Glass patterns (after Leon Glass, 1969) appear.

This technique is used in cartography to produce photomaps by superimposing grid lines, contour lines and other linear or textual mapping features over aerial photographs.

This can include craniofacial superimposition, which compares skulls of the deceased with images of them through the overlap of photographs.