Optical based impairment detection systems and methods

An impairment detection system is provided and includes an emitter, first and second beam selectors, a reference reflector, a sensor and a control module. The emitter is configured to emitter a first light signal. The first beam selector is configured to forward the first light signal to a touch probe. The reference reflector is configured to reflect the first light signal received from the first beam selector to generate a second reflected signal. The second beam selector is configured to receive (i) a first reflected signal from the touch probe based on reflection of the first light signal on an area of a person, and (ii) the second reflected signal. The sensor is configured to receive from the second beam selector the first reflected signal and the second reflected signal. The control module is configured to determine an impairment level of the person based on an output of the sensor.

INTRODUCTION

The present disclosure relates to impairment detection systems.

An impairment detection system for determining, for example, an alcohol level of an individual may include a light source, a touch probe, a beam splitter, two multi-spectral sensors (a reference sensor and a finger sensor) and a controller. During operation, a person being tested touches the touch probe. The light source emits a light signal having frequencies to excite alcohol molecules in a bloodstream of the person being tested. The light signal is directed to the touch probe and the reference sensor via the first beam splitter and corresponding fiber optic cables. The touch probe emits the first light signal as a laser beam, which is directed at a finger of the person. The laser beam excites alcohol molecules in the finger of the person and is reflected back as a reflected light signal to the touch probe. The reflected light is directed via a fiber optic cable to the finger sensor. The controller determines an alcohol level of the person based on outputs of the reference sensor and the finger sensor.

SUMMARY

An impairment detection system is provided and includes an emitter, a first beam selector, a reference reflector, a second beam selector, a sensor and a control module. The emitter is configured to emitter a first light signal. The first beam selector is configured to forward the first light signal to a touch probe. The reference reflector is configured to reflect the first light signal received from the first beam selector to generate a second reflected signal. The second beam selector is configured to receive (i) a first reflected signal from the touch probe based on reflection of the first light signal on an area of a person, and (ii) the second reflected signal. The sensor is configured to receive from the second beam selector the first reflected signal and the second reflected signal. The control module is configured to determine an impairment level of the person based on an output of the sensor.

In other features, an impairment detection system is provided and includes an emitter, a first beam selector, a second beam selector, a sensor and a control module. The emitter is configured to emitter a first light signal. The first beam selector is configured to forward the first light signal to a touch probe. The second beam selector is configured to receive the first light signal and a reflected light signal from the touch probe based on reflection of the first light signal on an area of a person. The sensor is configured to receive from the second beam selector the first light signal and the reflected light signal. The control module is configured to determine an impairment level of the person based on an output of the sensor.

DETAILED DESCRIPTION

An impairment detection system can include multiple multi-spectral sensors and other components. The multi-spectral sensors tend to be large and expensive. Sensitivities of the multi-spectral sensors tend to drift over time and outputs of the sensors tend to drift based on temperature. Also, differences between the outputs of two multi-spectral sensors tend to drift over time. A first one of the multi-spectral sensors (or reference sensor) is used as a reference to normalize an output of a second multi-spectral sensor (or finger sensor).

Impairment detection systems are set forth herein that include fewer sensors and components than traditional impairment detection systems. Disclosed embodiments include use of only a single multi-spectral sensor and thus include fewer multi-spectral sensors than traditional impairment detection systems. The disclosed impairment detection systems may be used to determine a chemical level (e.g., an alcohol level or level of some other chemical) of a person. The impairment detection systems may also be used to determine a level of a chemical compound or drug (e.g., tetrahydrocannabinol, cocaine, etc.). As an example, the impairment detection systems may be used to scan employees of a company as the employees are checking into work and indicate whether the employees are authorized to work or should be sent home based on respective impairment levels of the employees. As another example, the impairment detection system may be used to scan people prior to and/or upon entering a vehicle (an automobile, an airplane, a train, a boat, etc.) and prevent a person from entering and/or operating a vehicle if an impairment level of the person is greater than a predetermined threshold.

FIG. 1shows a first impairment detection system10that includes a control module12, an emitter14, a first beam selector16, a touch probe18, a reference reflector20, a first shutter22, a second shutter23, a second beam selector24and an impairment sensor26(e.g., a finger sensor or other suitable impairment sensor). The emitter14is a light beam or laser source that emits light at preselected frequencies and having preselected wavelengths to excite molecules in a bloodstream of a person. The preselected frequencies and other parameters, such as amplitudes, duty cycles, power level at each frequency, etc. may be determined for one or more chemicals and/or drugs. For example, if an alcohol level is being detected, the emitter14emits light having wavelengths of 1400-2600 nanometers (nm). In one embodiment, the emitter14emits infrared light in the range of 430 tera-hertz (THz) to 300 giga-hertz (GHz)). In one embodiment, light having wavelengths between 300-2600 nm is emitted. Light signals having frequencies outside the infrared spectrum may be emitted. One or more signals, each of which include one or more frequencies, may be emitted during a same period of time or the control module12may control the emitter to sequence through a predetermined pattern of frequencies and/or other parameters. The emitter14may include one or more light sources, one or more lasers, one or more mirrors, etc.

The touch probe18may emit and receive reflected light from excited molecules in an area on a person. Each of the beam selectors16,24includes a beam splitter, a digital micromirror device (DMD), or other beam selecting components. As a first example, each of the beam selectors16,24may be a beam splitter. As another example, the first beam selector16may be a DMD, which may be actuated by the control module12. The control module12may control an angular position of a mirror of the DMD. The second beam selector24may also be controlled by the control module12, such as when the second beam selector24includes a DMD. In one embodiment, the beam selector24operates as a combiner. The beam selectors16,24may include mirrors (e.g., half silver mirrors). The beam selectors16,24may operate as beam steering devices and (i) direct ends of fiber optic cables30,32to an end of fiber optic cable28or vice versa, and/or (ii) direct ends of fiber optic cables35,37to an end of fiber optic cable38or vice versa. In another embodiment, the beam selectors16,24include galvanometer based beam positioners or other beam selectors and/or beam steering devices.

The shutters22,23have ON and OFF states, permit passage of light when in the ON state, and prevent passage of light when in the OFF state. Although the shutters22,23are shown between (i) the second beam selector24and (ii) the touch probe18and the reference reflector20, the shutters22,23may be located between (a) the first beam selector16and (b) the touch probe18and the reference reflector20. The reference reflector20may include a mirror, a plate having a reflective painted surface, and/or other reflective components. The reference reflector20and the fiber optic cables32,36,37provide a reference channel on which a reflected (or reference) light signal is provided to indicate parameters of the first light signal. This allows the control module12to account for drift over time and/or drift due to changes in temperature.

The control module12signals the emitter14, which is a light beam (or laser) source to emit a light signal. The light signal is transmitted via a first fiber optic cable28to the first beam selector16. The light signal is split and provided to both the touch probe18via a second fiber optic cable30and to the reference reflector via a third fiber optic cable32. The touch probe18emits the light signal and receives reflected light, which is transmitted via fiber optic cables34,35through the second shutter23to the second beam selector24. The light signal provided to the reference reflector20is reflected by the reference reflector20through the shutter22to the second beam selector24via fiber optic cables36,37. The reference reflector20reflects the light from the fiber optic cable32to the fiber optic cable36. The light signals received at the second beam selector24are provided to the impairment sensor26via fiber optic cable38. The fiber optic cables28,30,34,35,36,37,38and other fiber optic cables disclosed herein optically couple corresponding devices, such as emitters, beam selectors, touch probes, shutters, attenuators, reference reflectors, and impairment sensors. The impairment sensor26is a multi-spectral sensor that operates as both a reference sensor to detect an output of a reference channel associated with the reference reflector20and as a measurement sensor to detect an output of a user channel associated with the touch probe18.

The control module12controls operation of the shutters, such that the second beam selector24receives either a light signal from the first shutter22or from the second shutter23, but not from both shutters22,23during a same period of time. The shutters22,23allow for rapid selection of the outputs of the reference and user channels. This allows for quick periodic detections of the outputs of the reference and user channels. The control module12receives outputs of the impairment sensor and, based on the outputs, determines an impairment level of the person being scanned.

FIG. 2shows the first impairment detection system10where at least a portion of the first impairment detection system10is packaged according to an embodiment of the present disclosure. The first impairment detection system10includes the control module12, the emitter14, the first beam selector16, the touch probe18, the reference reflector20, the first shutter22, the second shutter23, the second beam selector24, the impairment sensor26and the fiber optic cables28,30,32,34,35,36,37,38.

The emitter14, beam selectors1624, reference reflector20, shutters22,23, and impairment sensor26may be included in an impairment system housing40. Since the impairment detection system10includes a single sensor (i.e. the impairment sensor26), the envelope and volume of the impairment system housing40is minimized. In one embodiment, the control module12and/or the touch probe18are also included in the impairment system housing40.

FIG. 3shows a second impairment detection system50that includes a control module51, an emitter52, a first beam selector54, a touch probe56, a reference reflector58, a second beam selector62and an impairment sensor64(e.g., a finger sensor or other suitable impairment sensor). The control module51, emitter52, beam selectors54,62, touch probe56, and reference reflector58may operate and/or be configured similar as the control module12, emitter14, beam selectors16,24, touch probe18, reference reflector20and impairment sensor26ofFIG. 1.

The control module51signals the emitter52to generate a light signal, which is transmitted to the first beam selector54via a first fiber optic cable66. The first light signal is sent from the first beam selector54to the touch probe56via a second fiber optic cable68. The touch probe56emits the light signal and receives reflected light, which is transmitted via fiber optic cable70to the second beam selector62. The first light signal is also transmitted from the first beam selector54to the reference reflector58via fiber optic cable72. The light signal provided to the reference reflector58is reflected by the reference reflector58and transmitted to the second beam selector62via fiber optic cables74,76. The reference reflector58reflects the light from the fiber optic cable72to the fiber optic cable74. The light signals received at the second beam selector62are provided to the impairment sensor64via fiber optic cable78. In one embodiment, the second beam selector62is implemented as a DMD. Implementing the second beam selector62as a DMD instead of a beam splitter may minimize losses associated with the second beam selector62.

Depending on the amount of attenuation associated with the reference reflector58, an attenuator80may be included between the reference reflector58and the second beam selector62. Since light is passed from the first beam selector54to the second beam selector62, the light may be too intense for the impairment sensor64. Thus, the attenuator80may be included. The attenuator80may reduce amplitudes of the reflected light signal to be within an appropriate input dynamic range of the impairment sensor64. As an alternative the attenuator80may be connected between the first beam selector54and the reference reflector58. The attenuator80may be controlled by the control module102.

FIG. 4shows a third impairment detection system100that includes a control module100, an emitter104, a first beam selector106, a touch probe108, a reference reflector112, a shutter114, a second beam selector116, and an impairment sensor118(e.g., a finger sensor or other suitable impairment sensor). The control module102, emitter104, beam selectors106,116, touch probe108, and reference reflector112may operate and/or be configured similar as the control module12, emitter14, beam selectors16,24, touch probe18, reference reflector20and impairment sensor26ofFIG. 1.

The control module102signals the emitter104to generate a light signal, which is transmitted to the first beam selector106via a first fiber optic cable120. The first light signal is sent from the first beam selector106to the touch probe108via a second fiber optic cable122. The touch probe108emits the light signal and receives reflected light, which is transmitted via fiber optic cable124to the second beam selector116. The first light signal is also sent from the first beam selector106to the reference reflector via fiber optic cable126. The first light signal is reflected by the reference reflector112and transmitted to the second beam selector116and through the shutter114via fiber optic cables128,130. As an alternative, the shutter114may be connected between the first beam selector106and the reference reflector112. As another alternative the shutter114may be located between (i) the first beam selector106and (ii) the touch probe108or the reference reflector112. The reference reflector112reflects the light from the fiber optic cable126to the fiber optic cable128. The light signals received at the second beam selector116are provided to the impairment sensor118via fiber optic cable132.

Depending on the amount of attenuation associated with the reference reflector112, an attenuator119may be included between the first beam selector106and the reference reflector112. Since light is passed from the first beam selector106to the second beam selector116without passing through a shutter, the light may be too intense for the impairment sensor118. Thus, the attenuator119may be included. The attenuator119may reduce amplitudes of the reflected light signal to be within an appropriate input dynamic range of the impairment sensor118. As an alternative the attenuator119may be connected between the reference reflector112and the second beam selector116. The attenuator119may be controlled by the control module102.

FIG. 5shows a fourth impairment detection system150that includes a control module152, an emitter154, a first beam selector156, a touch probe158, shutters160,164, a second beam selector166, and an impairment sensor168(e.g., a finger sensor or other suitable impairment sensor). The control module152, emitter154, beam selectors156,166, touch probe158, shutters160,164, and impairment sensor168may operate and/or be configured similar as the control module12, emitter14, beam selectors16,24, touch probe18, shutters22,23and impairment sensor26ofFIG. 1.

The control module152signals the emitter154to generate a light signal, which is transmitted to the first beam selector156via a first fiber optic cable170. The first light signal is sent from the first beam selector156to the touch probe158via a second fiber optic cable172. The touch probe158emits the light signal and receives reflected light, which is transmitted via fiber optic cables174,176and the second shutter160to the second beam selector166. The first light signal is also sent from the first beam selector156to the second beam selector166via fiber optic cables178,180,182and the first shutter164. The light signals received at the second beam selector166are provided to the impairment sensor168via fiber optic cable184.

Depending on the amount of attenuation associated with the first shutter164, an attenuator185may be included between the first beam selector156and the first shutter164. Since light is passed from the first beam selector156to the second beam selector166without being reflected by a reference reflector, the light may be too intense for the impairment sensor168. Thus, the attenuator185may be included. The attenuator185may reduce amplitudes of the first light signal transmitted from the first beam selector156to the second shutter164to be within an appropriate input dynamic range of the impairment sensor168. As an alternative the attenuator185may be connected between the first shutter164and the second beam selector166. The attenuator185may be controlled by the control module152.

FIG. 6shows a fifth impairment detection system200that includes a control module202, an emitter204, a first beam selector206, a touch probe208, a shutter212, a second beam selector214and a impairment sensor216(e.g., a finger sensor or other suitable impairment sensor). The shutter212is optional and may not be included. The control module202, emitter204, beam selectors206,214, touch probe208, shutter212and impairment sensor216may operate and/or be configured similar as the control module12, emitter14, beam selectors16,24, touch probe18, shutter22and impairment sensor26ofFIG. 1.

The control module202signals the emitter204to generate a light signal, which is transmitted to the first beam selector206via a first fiber optic cable218. The first light signal is sent from the first beam selector206to the touch probe208via a second fiber optic cable220. In one embodiment, the first beam selector206is implemented as a DMD and controlled by the control module202. The touch probe208emits the light signal and receives reflected light, which is transmitted via fiber optic cable221to the second beam selector214. The first light signal is also sent from the first beam selector206to the second beam selector166via fiber optic cables222,224,226and the shutter212. The light signals received at the second beam selector214are provided to the impairment sensor216via fiber optic cable228.

An attenuator230may be included between the first beam selector206and the shutter212. Since light is passed from the first beam selector206to the second beam selector214without being reflected by a reference reflector, the light may be too intense for the impairment sensor216. Thus, the attenuator230may be included. The attenuator230may reduce amplitudes of the first light signal transmitted from the first beam selector206to the shutter212to be within an appropriate input dynamic range of the impairment sensor216. As an alternative, the attenuator230may be connected between the shutter212and the second beam selector206. The attenuator230may be controlled by the control module202.

The emitter204, beam selectors206,214, shutter212, impairment sensor216, and/or attenuator230may be included in an impairment system housing240. Since the impairment detection system200includes a single sensor (i.e. the impairment sensor216), the envelope and volume of the impairment system housing240is minimized. In one embodiment, the control module202and/or the touch probe208are also included in the impairment system housing240.

The reference module260determines reference parameters based on which to normalize a light signal received from a touch probe (e.g., one of the touch probes18,56,108,158,208). The reference parameters may indicate amplitudes, power levels, frequencies, duty cycles, etc. of light signals transmitted from a first beam selector (e.g., one of the first beam selectors16,54,106,156,206ofFIGS. 1-6) to a reference reflector (one of the reference reflectors20,58,112ofFIGS. 1-3) and/or a second beam selector (one of the second beam selectors24,62,116,166,214ofFIGS. 1-6). The normalization module262normalizes the light signal received from the touch probe (one of the touch probes18,56,108,158,208ofFIGS. 1-6). The normalization may be based on a normalization algorithm270stored in the memory252.

The impairment module264determines an impairment type and/or level based on results of the normalization performed by the normalization module262. The impairment type may refer to the chemical and/or corresponding impairment state of an individual. For example, if the chemical being detected is alcohol, the impairment type may indicate that legal intoxication due to alcohol is being determined. The results may include normalized power levels, amplitudes, and/or other normalized parameters. The impairment type and/or level may be determined based on an impairment algorithm, one or more transfer functions, and/or impairment tables272stored in the memory252. The impairment tables may relate normalization values to impairment types and/or levels.

The countermeasure module266performs a countermeasure based on the impairment level. The countermeasure may be determined based on a countermeasure table274that relates impairment levels to countermeasures. Some example countermeasures include: generating of an alert signal; limiting and/or preventing access to certain areas of a company; limiting and/or preventing access to one or more buildings; limiting and/or preventing computer access; reducing and/or changing an employee access and/or authorization level; preventing entrance into a vehicle; preventing operation of a vehicle, a vehicle engine and/or a vehicle motor; etc. Operations of the impairment detection systems ofFIGS. 1-6and modules250,252,254,256,258,260,262,264,266are further described below with respect to the method ofFIGS. 9-10.

FIG. 8shows a vehicle300including a vehicle system302and an impairment detection system304. The vehicle300includes a body control module306and an engine control module308. The body control module306controls operations of certain vehicle components, motors, and systems, such as window and door actuators310, interior lights312, exterior lights314, a trunk motor and lock315, seat position motors316, seat temperature control systems318vehicle mirror motors320(e.g., side view motors and rear view motor), and air-conditioning system322. The body control module306may control the components, motors, and systems based on a detected impairment level determined by the impairment system304. As an example, the body control module306may limit and/or prevent operation of certain components, motors, and/or systems until an impairment test is performed of a person entering the vehicle300. As another example, the body control module306may limit and/or prevent operation of certain components, motors and/or systems based on an impairment level determined by performing the impairment test.

The engine control module308controls operation of an engine330of the vehicle14. The engine330may include a starter motor332, a fuel system334, an ignition system336and a throttle system338. The engine control module308may control operation of the starter motor332, the fuel system334, the ignition system336and the throttle system338based on signals from the impairment system304. The impairment system304may, for example, signal the engine control module308to start and/or stop the engine330based on whether an impairment test has been performed and/or based on an impairment level of a vehicle operator, which may be received from the body control module306. The starting and stopping of the engine330may include: running the starter motor332; enabling the fuel system334to start supplying fuel to the engine330; disabling the fuel system334to stop supplying fuel to the engine330; enabling the ignition system336to provide spark to cylinders of the engine330; disabling spark to the cylinders of the engine330; and adjusting position of a throttle of the throttle system338.

The vehicle300may include a hybrid control module340that controls operation of one or more electric motors342. The hybrid control module340may control operation of the motors342based on whether an impairment test has been performed and/or based on an impairment level of a vehicle operator received from the body control module306. This may include running and/or stopping the motors342.

WhileFIG. 8shows a vehicle example for implementation of the impairment detection systems ofFIGS. 1-6and the control module and memory ofFIG. 7, the embodiments disclosed herein are applicable to non-vehicle implementations. For further defined structure of the modules ofFIGS. 1-8see below provided methods ofFIGS. 9-12and below provided definition for the term “module”. The systems disclosed herein may be operated using numerous methods, an example method is illustrated inFIG. 9.

FIG. 9illustrates an impairment and countermeasure method corresponding to the systems ofFIGS. 1 and 5and for determining and responding to an impairment level of a person. Although the following operations are primarily described with respect to the implementations ofFIGS. 1, 5 and 7, the operations may be modified to apply to other implementations of the present disclosure. The operations may be iteratively performed. The method may begin at400. At402, the emitter14(or154) generates a first light signal. At404, the first light signal is split via the first beam selector16(or156) and directed to (i) the touch probe18(or158), and (ii) a first shutter22(or shutter164).

At406, the touch probe18(or158) emits the first light signal at an area on a person (e.g., a tip of a finger of the person) and receives a first reflected light signal. At408, the first light signal may be received from the first beam selector16(or156) and (i) reflected by the reference reflector20to the first shutter22, or (ii) directly transmitted to the first shutter164. Operation406may be performed while operation408is performed.

At410, one of the shutters22,23(or160,164) is opened while the other one of the shutters22,23(or160,164) is closed. At412, one of the first reflected light signal and the second reflected light signal are received at the impairment sensor26(or168) via the second beam selector24(or166).

At414, the previously opened shutter is closed and the other one of the shutters22,23(or160,164) is opened. At416, the other one of the first reflected light signal and the second reflected light signal is received at the impairment sensor26(or168) via the second beam selector24(or166).

At418, the normalization module262normalizes the first reflected light signal based on the second reflected light signal. The second reflected light signal is used as a reference signal. At420, the impairment module264determines an impairment type and/or impairment level based on the normalized first reflected light signal and parameters of the first reflected light signal. The impairment module264may indicate whether the person is legally intoxicated based on the impairment level.

At422, the countermeasure module266may perform a countermeasure based on the impairment level. For example, if the impairment level is greater than a predetermined threshold, one or more countermeasures may be performed. This may include any of the above-stated countermeasures including generating an alert signal, preventing access to files on a computer, to a computer system, to an area of a building, to an interior of a vehicle, etc. This may include refraining from unlocking one or more doors. The countermeasures may include preventing activation/ignition of a vehicle and/or other countermeasures. The method may end at424.

FIG. 10shows an impairment and countermeasure method corresponding to the examples ofFIGS. 3 and 6. The method ofFIG. 10is described as if the shutter212ofFIG. 6is not included and the first light signal out of the first beam selector206is provided to the second beam selector214without passing through the shutter212. The second beam selector62(or214) may be a DMD or other beam selector. Although the following operations are primarily described with respect to the implementations ofFIGS. 3 and 6-7, the operations may be modified to apply to other implementations of the present disclosure. The operations may be iteratively performed. The method may begin at500. At502, the emitter52(or204) generates a first light signal. At504, the first light signal is split via the first beam selector54(or206) and directed to (i) the touch probe56(or208), and (ii) the second beam selector62(or214). The first light signal may be transmitted to the second beam selector62via the reference reflector58.

At506, the touch probe56(or208) emits the first light signal at an area on a person and receives a first reflected light signal. At508, the first light signal may be (i) reflected by the reference reflector58to the second beam selector62to provide a second reflected light signal, or (ii) directly transmitted to the second beam selector62. When directly transmitted, the first light signal is referred to the forwarded light signal. Operation506may be performed while operation508is performed.

At510, the second beam selector62(or214) selects for a first period of time a first selected one of (i) the first reflected light signal, or (ii) one of the second reflected light signal or the forwarded first light signal. At512, the impairment sensor64(or216) receives the output of the second beam selector62. At514, the second beam selector62(or214) selects for a second period of time a previously not selected (or second selected) one of (i) the first reflected light signal, or (ii) one of the second reflected light signal or the forwarded first light signal. At516, the impairment sensor64(or216) receives the second selected one of (i) the first reflected light signal, or (ii) one of the second reflected light signal or the forwarded first light signal.

At518, the normalization module262normalizes the first reflected light signal based on the second reflected light signal or the forwarded light signal. The second reflected light signal or the forwarded light signal is used as a reference signal. At520, the impairment module264determines an impairment type and/or impairment level based on the normalized first reflected light signal and parameters of the first reflected light signal. At522, the countermeasure module266may perform a countermeasure based on the impairment level. For example, if the impairment level is greater than a predetermined threshold, one or more countermeasures may be performed. This may include any of the above-stated countermeasures. The method may end at524.

FIG. 11shows an impairment and countermeasure method corresponding to the examples ofFIGS. 3 and 6. The method ofFIG. 11is described as if the shutter212ofFIG. 6is not included and the first light signal out of the first beam selector206is provided to the second beam selector214without passing through the shutter212. The first beam selector54(or206) may be a DMD or other beam selector. Although the following operations are primarily described with respect to the implementations ofFIGS. 3 and 6-7, the operations may be modified to apply to other implementations of the present disclosure. The operations may be iteratively performed. The method may begin at600. At602, the emitter52(or204) generates a first light signal.

At604, the first light signal is transmitted via the first beam selector54(or206) to the touch probe56(or208) or to the second beam selector62(or214) for a first period of time. At606, the second beam selector62(or214) receives one of a reflected light signal from the touch probe56(or208) or the first light signal from the first beam selector54(or206) and forwards the received signal to the impairment sensor64(or216).

At608, the first light signal is transmitted via the first beam selector to the other one of the touch probe56(or208) or the second beam selector62(or214) for a second period of time. At610, the second beam selector62(or214) receives the other one of the reflected light signal or the first light signal and forwards the received signal to the impairment sensor64(or216).

At612, the normalization module262normalizes the reflected light signal based on the first light signal. The first light signal is used as a reference signal. At614, the impairment module264determines an impairment type and/or impairment level based on the normalized first reflected light signal and parameters of the first reflected light signal. At616, the countermeasure module266may perform a countermeasure based on the impairment level. For example, if the impairment level is greater than a predetermined threshold, one or more countermeasures may be performed. This may include any of the above-stated countermeasures. The method may end at618.

FIG. 12shows an impairment and countermeasure method corresponding to the examples ofFIGS. 4 and 6. The method ofFIG. 12is described as if the shutter114(or212) ofFIGS. 4 and 6is included. Although the method ofFIG. 12is described as including the shutter114(or212) as being located between the reference reflector112and the second beam selector116or between the first beam selector206and the second beam selector214, the method ofFIG. 12may be modified for when the shutter114(or212) is located between the first beam selector106(206) and the touch probe108(or208) or between the touch probe108(or208) and the second beam selector116(or214). The first beam selector106(or206) and the second beam selector116(or214) may be configured respectively as a beam splitter and a beam combiner. Although the following operations are primarily described with respect to the implementations ofFIGS. 4 and 6-7, the operations may be modified to apply to other implementations of the present disclosure. The operations may be iteratively performed. The method may begin at700. At702, the emitter104(or204) generates a first light signal. At704the shutter114(or212) is opened.

At706, the first light signal is transmitted for a first period of time to both (i) the touch probe108(or208), and (ii) the second beam selector116(or214). At708, the touch probe emits the first light signal and receives a first reflected light signal. At709, the first light signal may be reflected off of the reference reflector112and passed through the shutter114prior to being received at the second beam selector116to provide a second reflected light signal.

At710, the first reflected light signal and either the first light signal or the second reflected light signal are received at the second beam selector116(or214). At711, the second beam selector116(or214) combines (i) the first reflected light signal and (ii) either the first light signal or the second reflected light signal.

At712, the control module102(or202) detects and stores a combined multi-spectral output from the impairment sensor118(or216). The combined multi-spectral output is based on the combination of (i) the first reflected light signal and (ii) either the first light signal or the second reflected light signal.

At714, the shutter114(or212) is closed. At716, the first light signal is transmitted from the emitter104(or204) to at least the touch probe108(or208). At718, the first light signal is emitted from the touch probe108(or208) and a reflected light signal (or third reflected light signal) is received at the touch probe108(or208). The third reflected light signal may match (i.e. have same power, frequencies, duty cycles, etc.) as the first reflected light signal. At719, the second beam selector116(or214) receives the third reflected light signal received at716.

At720, the third reflected light signal is forwarded to the impairment sensor118(or216) and an output of the impairment sensor118(or216) representative of the third reflected light signal is provided to the control module102(or202). At722, the control module102(or202) determines differences between (i) the output of the impairment sensor118(or216) that is representative of the third reflected light signal, and (ii) the combined multi-spectral output, to determine the second reflected light signal and/or parameters of the second reflected light signal. The parameters of the second reflected light signal are used as reference parameters.

At724, the normalization module262normalizes the first reflected light signal based on the second reflected light signal and/or corresponding properties of the second reflected light signal. The second reflected light signal or the forwarded light signal is used as a reference signal. The above-described operations706,708,709,710,711,712,716,718,719,720,722,724may be changed accordingly if the shutter114(or164) is located in a different location. At726, the impairment module264determines an impairment type and/or impairment level based on the normalized first reflected light signal and parameters of the first reflected light signal. At728, the countermeasure module266may perform a countermeasure based on the impairment level. For example, if the impairment level is greater than a predetermined threshold, one or more countermeasures may be performed. This may include any of the above-stated countermeasures. The method may end at730.

The above-described operations ofFIGS. 9-12are meant to be illustrative examples; the operations may be performed sequentially, synchronously, simultaneously, continuously, during overlapping time periods or in a different order depending upon the application. Also, any of the operations may not be performed or skipped depending on the implementation and/or sequence of events.

The above-described systems and methods account for drift in touch probe outputs and drift in sensor sensitivity by including reference channels having outputs indicative of parameters of light signals provided to the touch probes. This allows the outputs of the touch probes to be normalized and correlated to provide impairment levels. The reference channels also provide feedback to correct measured values for system diagnostics and system response adjustment. For example, the control module disclosed herein may adjust parameters of emitted signals based on detected outputs of the disclosed impairment sensors to account for drift and to assure that the parameters utilized are appropriate for the type of chemical and/or drug scanning being performed. The systems utilize a single light source and multi-spectral sensor to provide both reference samples and user samples without operator action to change a configuration of the systems. The use of a single light source and sensor minimize system complexity, size and costs. Also, components of the system may be located on a single side of a housing away from a touch probe. The systems and method provide enhanced reliability of impairment detection including compensating for laser, fiber optic and environmental variation over time.