An optical probe includes an optical window for transmitting light therethrough, an ultrasonic transducer for applying ultrasonic vibrations to the optical window for cleaning the optical window, and one or more light guides for transmitting light through the optical window to a measurement region and/or receiving light transmitted through the optical window from the measurement region. The ultrasonic transducer is coupled to the optical window via an elongate body adapted to transmit ultrasonic vibrations from the ultrasonic transducer to the window. The light guides communicate with the optical window adjacent the elongate body. An additional lens or light filter may be mounted adjacent the measurement window and/or the window itself may be adapted to incorporate a lens and/or light filter.

An optical smoke detector 1 includes an ultrasonic transducer 4 configured to cause oscillations in its housing 2 so as to dislodge accumulated particulate matter from the walls of a sensor chamber or a labyrinth of the smoke detector 1. Additionally or alternatively, the ultrasonic transducer 4 may be configured to cause oscillations that dislodge accumulated particulate matter from a light source or a light receiver of the smoke detector 1.

A determining unit 31 determines an image region of a foreign material in an imaged image generated by an imaging unit 22 by using an imaging optical system 21. A setting unit 32 sets a pressure, injection time, an injection direction of air injected to the foreign material, an injection pattern obtained by combining them and the like based on a determination result. A foreign material removal processing unit 33 adjusts air injection by an air injection adjusting unit 331 based on the setting by the setting unit 32 and injects from an air injecting unit 332 to the imaging optical system 21 to remove the foreign material adhering to the imaging optical system 21. The air is injected according to an adhesion condition of the foreign material, so that the foreign material adhering to the imaging optical system may be optimally removed.

A sensor for monitoring CO.sub.2 in a fluid regardless of the phase properties of the fluid, i.e., regardless of whether the fluid contacting the window is a liquid water-based phase, a liquid oil-based phase, a mixture of liquid water and liquid oil-based phases, or a gas phase. The sensor includes an internal reflection window for contacting with the fluid. A mid-infrared light source directs a beam of mid-infrared radiation into the window and the beam is internal reflected at an interface between the window and the fluid. The reflected beam is passed through three narrow bandpass filters which preferentially transmit mid-infrared radiation over bands of wavelengths corresponding to absorbance peaks of water, oil and CO.sub.2. The amount of CO.sub.2 is determined from the intensities of the mid-infrared radiation passing through the three filters.

A sensor for monitoring CO.sub.2 in a fluid regardless of the phase properties of the fluid, i.e., regardless of whether the fluid contacting the window is a liquid water-based phase, a liquid oil-based phase, a mixture of liquid water and liquid oil-based phases, or a gas phase. The sensor includes an internal reflection window for contacting with the fluid. A mid-infrared light source directs a beam of mid-infrared radiation into the window and the beam is internal reflected at an interface between the window and the fluid. The reflected beam is passed through three narrow bandpass filters which preferentially transmit mid-infrared radiation over bands of wavelengths corresponding to absorbance peaks of water, oil and CO.sub.2. The amount of CO.sub.2 is determined from the intensities of the mid-infrared radiation passing through the three filters

There may be provided a system comprising a spectroscopic device; wherein the spectroscopic device is configured to analyze a fluid of a pool.

There may be provided a system comprising a spectroscopic device; wherein the spectroscopic device is configured to analyze a fluid of a pool.

A determining unit 31 determines an image region of a foreign material in an imaged image generated by an imaging unit 22 by using an imaging optical system 21. A setting unit 32 sets a pressure, injection time, an injection direction of air injected to the foreign material, an injection pattern obtained by combining them and the like based on a determination result. A foreign material removal processing unit 33 adjusts air injection by an air injection adjusting unit 331 based on the setting by the setting unit 32 and injects from an air injecting unit 332 to the imaging optical system 21 to remove the foreign material adhering to the imaging optical system 21. The air is injected according to an adhesion condition of the foreign material, so that the foreign material adhering to the imaging optical system may be optimally removed.

A determining unit 31 determines an image region of a foreign material in an imaged image generated by an imaging unit 22 by using an imaging optical system 21. A setting unit 32 sets a pressure, injection time, an injection direction of air injected to the foreign material, an injection pattern obtained by combining them and the like based on a determination result. A foreign material removal processing unit 33 adjusts air injection by an air injection adjusting unit 331 based on the setting by the setting unit 32 and injects from an air injecting unit 332 to the imaging optical system 21 to remove the foreign material adhering to the imaging optical system 21. The air is injected according to an adhesion condition of the foreign material, so that the foreign material adhering to the imaging optical system may be optimally removed.

An optical smoke detector 1 includes an ultrasonic transducer 4 configured to cause oscillations in its housing 2 so as to dislodge accumulated particulate matter from the walls of a sensor chamber or a labyrinth of the smoke detector 1. Additionally or alternatively, the ultrasonic transducer 4 may be configured to cause oscillations that dislodge accumulated particulate matter from a light source or a light receiver of the smoke detector 1.