The Collaborative International Dictionary of English v.0.48:

Thermograph \Ther"mo*graph\, n. [Thermo- + -graph.] (Physics)
   An instrument for automatically recording indications of the
   variation of temperature.
   [1913 Webster]

WordNet (r) 3.0 (2006):

thermograph
    n 1: medical instrument that uses an infrared camera to reveal
         temperature variations on the surface of the body
    2: a thermometer that records temperature variations on a graph
       as a function of time [syn: thermograph,
       thermometrograph]