Method and apparatus using infrared photothermal radiometry (PTR) and modulated laser luminescence (LUM) for diagnostics of defects in teeth

A modulated imaging system for imaging dental tissue using modulated photothermal radiometry and luminescence, comprising:

• a function generator configured to provide a modulation waveform;
• at least one laser light source for irradiating a portion of a surface of a dental tissue with a beam of light of an effective wavelength, wherein laser light from said at least one laser light source is modulated according to said modulation waveform, and wherein modulated photothermal radiometric signals and modulated luminescence signals are responsively emitted from said portion of the surface;
• a mid-infrared camera for imaging said modulated photothermal radiometric signals and generating photothermal images, wherein the generation of the photothermal images by said mid-infrared camera is triggered according to said modulation waveform;
• a near-infrared camera for imaging said modulated luminescence signals and generating luminescence images, wherein the generation of the luminescence images by said near-infrared camera is triggered according to said modulation waveform;
• and
• a computing device including a software-based lock-in amplifier, wherein said computing device is configured to:
• collect, from said mid-infrared camera, a plurality of photothermal images during at least one modulation cycle of the modulation waveform, wherein the photothermal images are collected at a rate of at least four images per modulation cycle;
• collect, from said near-infrared camera, a plurality of luminescence images during at least one modulation cycle of the modulation waveform, wherein the luminescence images are collected at a rate of at least four images per modulation cycle;
• process the photothermal images with said software-based lock-in amplifier and demodulate the photothermal images into a photothermal phase image and a photothermal amplitude image;
• and
• process the luminescence images with said software-based lock-in amplifier and demodulate the luminescence images into a luminescence phase image and a luminescence amplitude image.