Imaging system for combined full-color reflectance and near-infrared imaging
An imaging system for acquisition of NIR and full-color images includes a light source providing visible light and NIR light to an area under observation, such as living tissue, a camera having one or more image sensors configured to separately detect blue reflectance light, green reflectance light, and combined red reflectance light/detected NIR light returned from the area under observation. A controller in signal communication with the light source and the camera is configured to control the light source to continuously illuminate area under observation with temporally continuous blue/green illumination light and with red illumination light and NIR excitation light. At least one of the red illumination light and NIR excitation light are switched on and off periodically in synchronism with the acquisition of red and NIR light images in the camera.
1. An imaging system for acquisition of NIR images and full-color images comprising:
a light source providing visible light and NIR light to an area under observation, the visible light comprising blue illumination light, green illumination light, and red illumination light, the blue illumination light being reflected from the tissue as blue reflectance light, the green illumination light being reflected from the tissue as green reflectance light, and the red illumination light being reflected from the tissue as red reflectance light;
a camera having one or more image sensors;
a controller in signal communication with the light source and the camera for illuminating the area under observation with the blue illumination light continuously and illuminating the area under observation with the red illumination light and the NIR illumination light, wherein at least one of the red illumination light and NIR illumination light is switched on and off periodically according to a predetermined timing scheme, and
simultaneously acquiring a first image signal corresponding to the blue illumination light, a second image signal corresponding to the green illumination light, and a third image signal corresponding to the red illumination light and NIR illumination light; and
determining the red reflectance light and detected NIR light from the third image signal, based on the timing scheme, and
wherein the imaging system is configured to generate the full-color reflectance and NIR images of the area under observation.
2. The imaging system of claim 1 , wherein the area under observation is alternatingly illuminated by the light source with red illumination light and NIR illumination light.
3. The imaging system of claim 1 , wherein the light source comprises
an illuminator emitting a substantially constant intensity of visible light and NIR light over a continuous spectral range, and
a plurality of filters disposed between the illuminator and the area under observation for transmitting temporally continuous blue light and temporally discontinuous red light and discontinuous NIR light.
4. The imaging system of claim 1 , wherein the light source comprises
an illuminator emitting a substantially constant intensity of visible light and NIR light over a continuous spectral range,
first dichroic means for separating the visible light and NIR light into blue and red light and NIR light,
shutter means for transforming the separated red light and NIR light into temporally discontinuous red light and discontinuous NIR light, and
second dichroic means for combining the blue light, the temporally discontinuous red light and the temporally discontinuous NIR light for transmission to the area under observation.
5. The imaging system of claim 1 , wherein the light source comprises
a first illuminator emitting a substantially constant intensity of green and blue light,
a second illuminator producing switched red light,
a third illuminator producing switched NIR light, and
dichroic means for combining the switched red light and the switched NIR light with the green and blue light for transmission to the area under observation.
6. The imaging system of claim 5 , wherein the switched red light and the NIR light are produced by interrupting a continuous intensity light beam of the red light and the NIR light by a shutter or chopper.
7. The imaging system of claim 5 , wherein the switched red light and the NIR light are produced by electrically switching the second illuminator and the third illuminator on and off.
8. The imaging system of claim 1 , wherein the one or more image sensors are configured to employ an interlaced scan.
9. The imaging system of claim 1 , wherein the predetermined timing scheme includes alternating the red illumination light and NIR illumination light.
10. The imaging system of claim 9 , wherein the duration of illumination with the red illumination light is longer than the duration of illumination with the NIR illumination light.
11. The imaging system of claim 1 , where the controller controls the light source such that the green illumination light continuously illuminates the area under observation.
12. The imaging system of claim 1 , wherein the camera comprises a single sensor.
13. The imaging system of claim 12 , wherein the single sensor comprises a three-color RGB sensor.
14. The imaging system of claim 1 , wherein the light source comprises one or more solid state sources.
15. The imaging system of claim 1 , wherein the blue, green, and red illumination light are produced by blue, green, and red LEDs, respectively.
16. The imaging system of claim 1 , wherein the one or more image sensors comprise a single image sensor having pixels, each pixel responsive to one of the blue reflectance light, the green reflectance light, and the red reflectance light and NIR light returned from the area under observation.
17. The imaging system of claim 16 , wherein the single image sensor comprises a mosaic filter array.
18. The imaging system of claim 1 , wherein the imaging system is configured as an endoscope.
19. The imaging system of claim 1 , wherein the NIR light detected by the camera is fluorescent light.