An apparatus comprising: a sensor network comprising: a first plurality of rows, a second plurality of columns and a third plurality of sensor elements wherein each sensor element is associated with a unique combination of a row and a column but not every unique combination of row and column is associated with a sensor; selection circuitry configured to concurrently select a group of the first plurality of rows; reading circuitry configured to concurrently read columns during a concurrent selection; and control circuitry configured to determine the group of the first plurality of rows that are concurrently selected.