Abstract: The invention relates to a technique for providing a so-called `pedestal` voltage on the rear surface of the target of a pyroelectric camera. This is a positive voltage required to ensure efficient discharge, by the electron beam, of the pyroelectric charge. In the invention, the pyroelectric material is in the form of a plurality of islands of pyroelectric material connected individually to the signal plate. Each island is coated on its rear surface and on at least one side, by a conductive film. By applying a positive bias voltage to the signal plate, the rear surface of the pyroelectric islands are similarly biassed to provide the pedestal.