Method and apparatus for optical measurements under ambient light conditions
Examples of a spectroscopy system with a specially design ambient illumination system are disclosed. The ambient illumination system comprises one or more light emitting diodes (LEDs) that provide illumination light in the wavelength of 400-785 nm. The ambient illumination system can further comprise a filter to block light above 785 nm. The filter can be placed directly in front of LED emitters. The LEDs can be white LEDs or RGB LEDs. The spectroscopy system can further comprise a control system that can receive a signal from the spectral probe when the spectral measurements commence and can instantaneously send a signal to automatically switch off the ambient illumination system and to receive a signal from the spectral probe when the spectral measurements are terminated and automatically switch on the ambient illumination system. Examples of methods of operating the spectroscopy system and the ambient illumination system are disclosed.
1. A spectroscopy system, the system comprising:
a spectroscopy probe;
a light source producing an illumination light to illuminate a subject under examination and to produce returning radiation;
a detector coupled to capture the returned radiation and measure a spectrum of the returned radiation;
a display in communication with the detector to display the measured spectrum;
an ambient light illumination source comprising one or more light emitting diodes (LEDs) to generate ambient light in a surrounding area where a spectral measurement is taken; and
a control system in communication with the light source and the display, the control system being configured to receive an input signal from the light source when the light source is on and to produce an output signal to turn off the display during the spectral measurements.
2. The spectroscopy system of claim 1 , wherein the control system is in communication with the ambient light illumination source, the controller producing an output signal to the ambient light illumination source to turn it off upon a receipt of the input signal from the light source.
3. The spectroscopy system of claim 2 , wherein the control system further comprises a switch in communication with the control system to simultaneously activate the light source and deactivate the one or more LEDs.
4. The spectroscopy system of claim 2 , wherein the control unit further communicates with the detector such that when the detector detects the returning radiation the control system produces an output signal to the one and more LEDs to turn them on.
5. The spectroscopy system of claim 1 , further comprises a filter configured to pass visible components of the ambient illumination light and to block near infrared (NIR) component of the ambient illumination light.
6. The spectroscopy system of claim 5 , wherein the filter is configured to cut out the light with wavelength above 780 nm.
7. The spectroscopy system of claim 5 , wherein the filter is mounted directly in front of the one or more LEDs.
8. The spectroscopy system of claim 1 , wherein the one or more LEDs are optimized RGB LEDs, the red LED being shifted to generate light in a 620-680 nm wavelength range.
9. The spectroscopy system of claim 1 , further comprising a long pass filter placed before the detector configured to block light bellow 785 nm wavelength and pass light above 785 nm wavelength.