Apparatus for caries detection
View Patent ↗An apparatus for obtaining an image of a tooth having at least one light source providing incident light having a first spectral range for obtaining a reflectance image from the tooth and a second spectral range for exciting a fluorescence image from the tooth. A polarizing beamsplitter in the path of the incident light from both sources directs light having a first polarization state toward the tooth and directs light from the tooth having a second polarization state along a return path toward a sensor, wherein the second polarization state is orthogonal to the first polarization state. A first lens in the return path directs image-bearing light from the tooth toward the sensor, and obtains image data from the portion of the light having the second polarization state. A long-pass filter in the return path attenuates light in the second spectral range.
1. A method for imaging a tooth surface using fluorescent imaging with reflectance enhancement, comprising:
providing incident white light a first spectral range for obtaining a back-scattered reflectance image from tooth enamel;
providing incident light having a second spectral range for exciting a fluorescence emission from the tooth enamel for obtaining a fluorescence image of the tooth surface;
directing the incident white light having a first polarization state toward the tooth surface and directing reflected incident white light from the tooth surface having a second polarization state along a return path toward a 2-D digital sensor, wherein the second polarization state is orthogonal to the first polarization state;
directing emitted and reflected image-bearing light from the tooth surface along the return path toward the 2-D digital sensor for obtaining image data from the portion of the light having the second polarization state; and
attenuating light in the second spectral range along the return path and transmitting light in the first spectral range along the return path.
2. The method according to claim 1 wherein directing the reflected image-bearing light toward the sensor comprises forming an intermediate image in the return path and further comprising re-imaging the intermediate image onto the sensor.
3. The method according to claim 1 further comprising displaying an image obtained by the 2-D digital sensor.
4. The method according to claim 3 wherein the incident light and 2-D digital sensor are provided using a hand-held probe and wherein movement of the probe from one position to another is displayed as movement in the same direction.
5. The method of claim 1 wherein the directing the incident white light having a first polarization state toward the tooth surface and directing reflected incident white light from the tooth surface having a second polarization state along a return path toward a 2-D digital sensor, is accomplished by directing the light through imaging optics having an image size that substantially fills the sensor.
6. The method of claim 1 wherein attenuating light in the second spectral range and transmitting light in the first spectral range is accomplished by providing a long-pass filter in the return path.
7. The method of claim 6 further comprising attenuating ultraviolet and shorter wavelength visible light and transmitting longer wavelength light.