Abstract: The present invention comprises a method and apparatus for determining actual temperature, reflectivity and fluorescence of a surface and comprises in the preferred embodiment a two-dimensional focal plane array of rapidly tunable infrared detectors, 11, adapted to detect the emitted infrared flux from a surface of interest, 10, across pre-selected spectral segments in the 4-15 .mu.m range. The invention further comprises a computer having deconvolution algorithms, 13, for isolating the effects of reflectivity, fluorescence and environmental factors affecting infrared emission for each pixel of the generated image at various spectral segments in the 4-15 .mu.m range. The device further includes means for generating images of temperature, emissivity and fluorescence for diagnostic use.