Karen Sparck Jones & Julia R. Galliers, Evaluating Natural Language Processing Systems: An Analysis and Review. Lecture Notes in Artificial Intelligence 1083

A heat-sensitive type multi-gradation image recording apparatus adapted for use with a conventional two-valued recording apparatus including a simple device for identifying image signal levels for recording multi-gradation images. A plurality of heat generating resistance elements are arranged one-dimensionally in correspondence to picture elements. A video signal is converted into a plurality of binary video signals using different threshold level values. Electrical energy is supplied to the heat generating elements controlled by the binary video signals to record and image in an overlap mode.