JP5266414B2 - Ethyl alcohol detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ethyl alcohol detector which detects ethyl alcohol in the blood from infrared rays emitted from a driver and is utilized for preventing driving under the influence of liquor. <P>SOLUTION: An imaging control part 42 captures a first subject image of a first wavelength band containing the absorbing wavelength &lambda;1 of ethyl alcohol from the infrared radiated light of a subject 20 or reflected light and a second subject image of a second wavelength band containing the other absorbing wavelength &lambda;2 of a disturbance substance having an absorbing wavelength in the same first wavelength band as ethyl alcohol by replacing a filter 16 and stores them in a memory 38. A reference image registration part 40 stores a first subject image captured by the imaging control part 42 when a registration mode is set in a nonvolatile memory 36 as a reference image in advance. An ethyl alcohol detection part 44 calculates an ethyl alcohol-containing degree on the basis of the first subject image and the reference image, and a disturbance substance detection part 46 calculates a disturbance degree on the basis of the second subject image and the reference image. A determining part 44 determines the detection or non-detection of ethyl alcohol on the basis of the ethyl alcohol-containing degree and the disturbance degree. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

The present invention relates to an ethyl alcohol detection device that detects ethyl alcohol dissolved in blood by drinking based on infrared rays radiated from a human body and determines drunk driving or the like.

  2. Description of the Related Art Conventionally, an apparatus for preventing drunk driving is configured so that ethyl alcohol contained in a driver's breath is detected by a gas sensor so that the automobile is not started (Patent Document 1).

In general, the concentration of alcohol contained in exhaled breath is proportional to the alcohol concentration in blood. The standard for drunken driving stipulated by law is an alcohol concentration of 0.15 mg / L in exhaled breath, which corresponds to a blood alcohol concentration of 0.03%. For this reason, by measuring the alcohol concentration in exhaled breath, it is possible to detect driving and prevent driving.

Japanese Patent Laid-Open No. 8-150853

  However, in such a conventional anti-drinking device, the air in the space near the head where the driver is located is sucked by a fan and alcohol is indirectly detected by a gas sensor. Compared to the case where the alcohol concentration is directly collected and the alcohol concentration is measured, the measured value is lower than the actual alcohol concentration in the expiration, and there is a possibility that the drunk driving cannot be prevented reliably.

  In addition, since the sensitivity of gas sensors that detect alcohol changes due to the adhesion of foreign substances or oxidation during use, calibration is required to automatically adjust the sensitivity, and maintenance such as periodic cleaning and inspections must be performed. There is a problem that the detection accuracy cannot be maintained.

It is an object of the present invention to provide a maintenance-free ethyl alcohol detection device that can be used for preventing alcohol consumption by detecting ethyl alcohol in blood from infrared rays emitted by a driver.

(Apparatus using infrared image sensor)
The present invention provides an ethyl alcohol detector using an infrared imaging device. The ethyl alcohol detection device of the present invention,
An image sensor having sensitivity in the infrared wavelength band;
An optical system for forming a subject image on an image sensor;
A first filter that selectively transmits infrared light in a first wavelength band including an absorption wavelength of ethyl alcohol from a subject;
A second filter that selectively transmits infrared light in a second wavelength band including other absorption wavelengths of disturbance substances having an absorption wavelength in the same first wavelength body region as ethyl alcohol from a subject;
An imaging control unit that captures an image of a first subject image formed through the first filter and a second subject image formed through the second filter and stores the image in a memory;
A reference image registration unit that stores and holds, as a reference image, a first subject image formed through the first filter by the imaging control unit when the registration mode is set;
An ethyl alcohol detector that calculates the ethyl alcohol content corresponding to the ethyl alcohol concentration based on the first subject image in the memory and the reference image in the nonvolatile memory;
A disturbance substance detector that calculates a disturbance degree corresponding to the concentration of the disturbance substance based on the second subject image stored in the memory and the reference image of the nonvolatile memory;
A determination unit for determining the detection of ethyl alcohol based on the ethyl alcohol content and the disturbance degree,
It is provided with.

Here, the first filter selectively transmits infrared light in a wavelength band including 2.77 μm or 3.37 μm as the first wavelength band,
When the disturbance substance is menthol, the second filter selectively transmits infrared light in a wavelength band including 3.28 μm as the second wavelength band, and when the disturbance substance is stearic acid, the second filter has a second wavelength band of 5. Infrared light in a wavelength band including 88 μm is selectively transmitted.

The reference image registration unit calculates the reference received light amount as the sum or average value of the pixels constituting the reference image and stores it in the nonvolatile memory.
The ethyl alcohol detection unit calculates the ethyl alcohol content based on the first received light amount calculated as the sum or average value of the pixel values of the first subject image and the reference received light amount of the nonvolatile memory,
The disturbance substance detection unit calculates the disturbance degree based on the second subject received light amount calculated as the sum or average value of the pixel values of the second subject image and the reference received light amount of the nonvolatile memory.

The ethyl alcohol detection unit calculates the alcohol content as a subtraction value or division value of a reference light reception amount with respect to the first subject light reception amount, a subtraction value or division value multiplied by a predetermined coefficient, or a sum or average value of square error values. And
The disturbance substance detection unit calculates the disturbance degree as a subtraction value or division value of a reference light reception amount with respect to the second subject light reception amount, a subtraction value or division value multiplied by a predetermined coefficient, or a sum or average value of square error values. .

(Apparatus using infrared detection element)
The present invention provides an ethyl alcohol detector using one or more infrared detection elements. The ethyl alcohol detection device of the present invention,
An infrared sensor comprising one or more infrared light receiving elements;
An optical system that forms an object image on the infrared sensor;
A first filter that selectively transmits infrared light in a first wavelength band including an absorption wavelength of ethyl alcohol from a subject;
Selectively select infrared light in a second wavelength band including other absorption wavelengths of disturbance substances having an absorption wavelength in the same first wavelength body region as ethyl alcohol from the subject and including wavelengths that are not absorption wavelengths of ethyl alcohol A second filter to transmit;
A light reception control unit for detecting a first light reception signal of the subject received through the first filter and a second light reception signal of the subject received through the second filter by the infrared sensor, and storing them in the memory; ,
A reference light reception signal registration unit that stores and holds the first light reception signal received through the first filter by the light reception control unit as a reference light reception signal when the registration mode is set;
An ethyl alcohol detector that calculates an ethyl alcohol content corresponding to the ethyl alcohol concentration based on the first light receiving signal of the memory and the reference light receiving signal of the nonvolatile memory;
A disturbance substance detection unit that calculates a disturbance degree corresponding to the concentration of the disturbance substance based on the second light reception signal of the memory and the reference light reception signal of the nonvolatile memory;
A determination unit for determining the detection of ethyl alcohol based on the ethyl alcohol content and the disturbance degree,
It is provided with.

Here, the first filter selectively transmits infrared light in a wavelength band including 2.77 μm or 3.37 μm as the first wavelength band,
When the disturbance substance is menthol, the second filter selectively transmits infrared light in a wavelength band including 3.28 μm as the second wavelength band, and when the disturbance substance is stearic acid, the second filter has a second wavelength band of 5. Infrared light in a wavelength band including 88 μm is selectively transmitted.

The ethyl alcohol detection unit calculates the ethyl alcohol content based on the first subject light reception signal of the memory and the reference light reception signal of the nonvolatile memory,
The disturbance substance detection unit calculates a disturbance degree based on the second subject light reception signal in the memory and the reference light reception signal in the nonvolatile memory.

The ethyl alcohol detection unit calculates the ethyl alcohol content as a subtraction value or division value of a reference light reception signal with respect to the first subject light reception signal, a subtraction value or division value multiplied by a predetermined coefficient, or a sum or average value of square error values. Calculate
The disturbance substance detection unit calculates the disturbance degree as a subtraction value or division value of a reference light reception signal with respect to the second subject light reception signal, a subtraction value or division value multiplied by a predetermined coefficient, or a sum or average value of square error values. .

In the infrared sensor, the first filter, each of the one or more second filters, and the infrared light receiving element are combined and arranged in the sensor housing.

  According to the present invention, a characteristic absorption spectrum due to ethyl alcohol in the capillary is detected from infrared radiation from the human body due to the temperature of the driver, in particular from infrared radiation from the face where the skin is exposed, It is possible to obtain the ethyl alcohol content corresponding to the blood alcohol concentration, and accurately determine the driver's drunk driving etc. from this ethyl alcohol content and take appropriate measures such as alerting and driving prevention it can.

  In addition, menthol contained in cosmetics causes disturbance due to having an absorption spectrum at the same wavelength as that of ethyl alcohol, but by detecting the absorption spectrum of menthol's intrinsic wavelength not present in ethyl alcohol as the degree of disturbance, it depends on cosmetics. An erroneous detection of ethyl alcohol can be reliably prevented.

  In addition, the content of ethyl alcohol is detected as a value such as the ratio or difference between the received light amount of the absorption spectrum of the intrinsic wavelength of the ethyl alcohol and the received light amount of another wavelength without the absorption spectrum. Without being received, ethyl alcohol in the capillary can be accurately detected with a high S / N ratio.

  In addition, since the ethyl alcohol content is detected from the ethyl alcohol absorption spectrum in the infrared light from the subject, maintenance such as sensitivity adjustment and cleaning inspection such as alcohol detection with a conventional gas sensor is unnecessary, and it can be performed for a long time. It is possible to detect the ethyl alcohol content of the human body, which is the cause of drunk driving, with stable high accuracy.

Also acquired in registration mode at the start of use, based on the subject image of the ethyl alcohol absorption wavelength obtained by imaging normal subjects without ethyl alcohol in the blood used to determine the ethyl alcohol content and disturbance level By registering in advance in the non-volatile memory, it is not necessary to take a subject image in a different wavelength band where there is no ethyl alcohol absorption spectrum each time, and the menthol that causes the ethyl alcohol absorption wavelength and disturbance factors Since it is only necessary to acquire the subject image for the two wavelength bands of the absorption wavelength unique to the optical system, the optical system for capturing the infrared image of the subject and its switching control can be simplified and the cost can be reduced.

The block diagram which showed embodiment of the ethyl alcohol detection apparatus by this invention Explanatory drawing showing the infrared camera used in this embodiment Explanatory diagram showing the wavelength spectrum distribution of ethyl alcohol Explanatory drawing which showed extraction of the feature area in this embodiment The flowchart which showed the detection process of the ethyl alcohol by embodiment of FIG. The flowchart which showed the detail of the reference | standard image light reception amount registration process in FIG.5 S1 Explanatory drawing which showed the infrared camera using the filter switching unit used by this embodiment The block diagram which showed other embodiment of the ethyl alcohol detection apparatus using an infrared sensor Explanatory drawing which showed the infrared sensor of FIG. The flowchart which showed the detection process of the ethyl alcohol by embodiment of FIG. The flowchart which showed the detail of the reference | standard light reception signal registration process in step S33 of FIG. The block diagram which showed other embodiment of the ethyl alcohol detection apparatus using a multi-infrared sensor. Explanatory drawing which showed the infrared sensor of FIG. The flowchart which showed the detection process of the ethyl alcohol by embodiment of FIG. The flowchart which showed the detail of the reference | standard light reception signal registration process in step S54 of FIG. The block diagram which showed other embodiment of the ethyl alcohol detection apparatus using the multi-infrared sensor with a built-in filter Explanatory drawing which showed the infrared sensor of FIG. The flowchart which showed the detection process of the ethyl alcohol by embodiment of FIG. A flowchart showing details of the reference light reception signal registration processing in step S81 of FIG.

  FIG. 1 is a block diagram showing an embodiment of an ethyl alcohol detection device according to the present invention mounted on a vehicle. In FIG. 1, the ethyl alcohol detection device 10 is provided with a CPU 26 representative of the hardware environment of the computer. The CPU 26 is an infrared camera 12 having an optical system 22 and a CCD image sensor 24 as an image pickup device. A camera control unit 14, a wavelength tunable filter 16, and a filter driving unit 18 are provided.

  FIG. 2 is an explanatory view showing an infrared camera using a wavelength tunable filter used in the first embodiment of FIG. In FIG. 2, a wavelength tunable filter 16 is provided between the optical system including the objective lens 64 and the imaging lens 66 of the infrared camera 12, and the transmission wavelength of the wavelength tunable filter 16 is controlled by the filter driving unit 18.

  A CCD imaging device 24 having sensitivity in the infrared wavelength band is disposed in the infrared camera 12 and picks up an infrared image in the wavelength band that has passed through the wavelength tunable filter 16 imaged by the imaging lens 66.

  The wavelength tunable filter 16 is known as a Fabry-Perot interference filter. For example, a pair of glass substrates on which a transparent metal film serving as a reflective film such as Au having a thickness of about 200 to 300 angstroms is deposited on opposite surfaces are formed. A pair of glass substrates are arranged opposite to each other with a piezoelectric element interposed therebetween, and a minute interval is set therebetween. The piezoelectric elements between the glass substrates can change the distance between the substrates by receiving a DC voltage applied by the filter driving unit 18.

  The wavelength tunable filter 16 transmits light with a plurality of transmission spectra distributed to the incident light from the one glass substrate side due to interference action caused by multiple reflections between the transparent metal films. As such a tunable filter 16, for example, one disclosed in Japanese Patent Laid-Open No. 8-285688 can be used.

  Referring to FIG. 1 again, the CPU 26 provided in the ethyl alcohol detection apparatus 10 is connected to the IF 30, the output IFs 32 and 34, the nonvolatile memory 36 using flash memory and EEPROM, and the memory 38 using RAM via the bus 28. Is connected.

  The camera control unit 14 is connected to the IF 30, and when an ethyl alcohol detection request is generated such as when the vehicle engine is started, the image of the driver 18 captured by operating the wavelength tunable filter 16 and the infrared camera 12 is digitally displayed. The image data is converted and stored in the memory 38 as a λ1 image 56 and a λ2 image 58. The image capturing control operation using the infrared camera 12 is performed by the image capturing control unit 42 provided in the CPU 26.

  A display unit 60 is connected to the output IF 32, and a control unit 62 is connected to the output IF 34. The display unit 60 displays the detection result processed by the ethyl alcohol detection device 10, for example, whether or not the driver 20 is drunk. The display unit 60 is also provided with an audio output function. When the ethyl alcohol detector 10 determines that the driver 20 has drunk driving, the control unit 62 performs drunk driving prevention control or the like so that the engine cannot be started, for example.

  The CPU 26 is provided with a reference image registration unit 40, an imaging control unit 42, an ethyl alcohol detection unit 44, a disturbance substance detection unit 46, and a determination unit 48 as functions realized by executing the program.

  In the ethyl alcohol detection device 10 of the present embodiment, the ethyl alcohol contained in the capillaries directly under the skin such as the face is detected based on the drunk state of the driver 20. The detection of ethyl alcohol contained in capillaries is based on detecting the attenuation by the absorption spectrum of a specific wavelength due to ethyl alcohol in infrared radiation or infrared reflected light from the human body due to the body temperature of the driver.

FIG. 3 is an explanatory diagram showing the wavelength spectrum distribution of ethyl alcohol detected in the present embodiment. Ethyl alcohol C ₂ H ₅ OH has an absorption spectrum derived from its molecular structure at specific wavelengths such as 2.77 μm, 3.37 μm, and 9.5 μm. For example, the absorption spectrum at a wavelength of 2.77 μm is a wavelength band in which ethyl alcohol molecules absorb as the —CH ₃ bond stretches in ethyl alcohol.

  Therefore, the wavelength tunable filter 16 is controlled by the λ1 filter as the first filter that selectively transmits the first wavelength band including λ1 = 2.77 μm as the absorption wavelength λ1 of ethyl alcohol out of the infrared light from the driver. When the infrared light is monitored, in the state where ethyl alcohol is contained in the capillary blood vessel, that is, in the drunken state, the infrared light in the first wavelength band including λ1 = 2.77 μm becomes the ethyl alcohol concentration in the capillary blood vessel. The amount of received light I1 obtained from each pixel in the λ1 image captured by the image sensor at this time is small.

  Further, in the present embodiment, the registration mode when starting to use the apparatus includes a wavelength λ1 = 2.77 μm that gives an absorption spectrum of normal ethyl alcohol in which no ethyl alcohol is contained in the capillaries. A λ1 image captured by controlling the wavelength tunable filter 16 as a λ1 filter is stored in the nonvolatile memory 36 as the reference image 50, and the received light amount Ith obtained from the reference image 50 is stored in the nonvolatile memory 36 as the reference received light amount 52. Yes.

Here, in the state before using the apparatus, the reference light reception amount obtained as the design value at the stage of manufacturing the apparatus is stored in advance in the nonvolatile memory 36 as the default value (Ith) ₀ , and the registration mode is executed. The default value (Ith) ₀ is updated to the user-specific value Ith.

  As the reference received light amount Ith obtained from the reference image in the registration mode, a received light amount corresponding to an infrared radiation amount radiated (or reflected) from the human body in a normal state without ethyl alcohol is obtained.

Here, assuming that λ1 received light amount during drinking with an absorption spectrum of ethyl alcohol is I1, the ethyl alcohol content A is given by the following equation as a ratio with the normal received light amount Ith.
A = Ith / I1 (1)

  Since the λ1 received light amount I1 in the equation (1) decreases as the ethyl alcohol concentration increases, the ethyl alcohol content A has a relationship of increasing according to the ethyl alcohol concentration. Further, since the λ1 received light amount I1 is substantially equal to the reference received light amount Ith in the normal state, the alcohol content level H becomes a value in the vicinity of A = 1.

If the ethyl alcohol content A given by the equation (1) is equal to or greater than a predetermined threshold Ath, it can be determined that ethyl alcohol has been detected, and if it is less than the threshold, it can be determined that ethyl alcohol has not been detected. The threshold Ath in this case is Ath = αA ₀ when the normal alcohol content is A ₀ and is multiplied by a predetermined coefficient α of 1 or more to absorb the error.
What should I do? For example, if α = 1.2, Ath = 1.2A ₀ is given.

  The calculation of the ethyl alcohol content A in this embodiment is performed by the reference image registration unit 40, the imaging control unit 42, and the ethyl alcohol detection unit 44 provided in the CPU 26 of FIG.

  The reference image registration unit 40 controls the camera control unit 14 by the imaging control unit 42 and sets the wavelength variable by the operation of the filter driving unit 18 when setting the registration mode for starting use of the ethyl alcohol detection device 10 mounted on the vehicle. The filter 16 is switched to a λ1 filter that selectively transmits the first wavelength band including the absorption wavelength λ1 = 2.77 μm of ethyl alcohol, and the subject image formed through the wavelength tunable filter 16 is nonvolatile as the reference image 50. Store in the memory 36.

  Further, the reference image registration unit 40 calculates the total or average value of the pixels constituting the reference image 50 as Ith, and stores this value Ith in the nonvolatile memory 36 as the reference received light amount 52.

In the stage before the start of use for performing registration, a default reference received light amount (Ith) ₀ obtained as a design value is registered in advance in the nonvolatile memory 36. For this reason, when the registration process by setting the registration mode is not performed, the default reference received light amount (Ith) ₀ is used for the ethyl alcohol detection process.

  Further, the reference image registration unit 40 generates a feature region extraction image 54 for extracting a driver's feature region used for ethyl alcohol detection from the reference image 50, and stores this as a template. The feature region extraction image 54 is also used for extracting a feature region when obtaining a reference light reception amount from the reference image 50.

  The imaging control unit 42 operates when an ethyl alcohol detection request is generated when the vehicle engine is started. The imaging driver 42 functions as a λ1 filter by the switching operation of the wavelength tunable filter 16 by the filter driving unit 18 and as a λ2 filter that will be clarified later. While switching to the wavelength band, an image of the driver's face was picked up by the infrared camera 12 and formed through the λ1 image 56 and the λ2 filter, which are the first subject images formed through the λ1 filter. The λ2 image 58 that is the second subject image is stored in the memory 38.

  Here, in this embodiment, by detecting the absorption spectrum characteristic of the infrared rays emitted from the human body due to body temperature due to ethyl alcohol in the blood, the ethyl alcohol content corresponding to the blood alcohol concentration is obtained. When the signal amount of the CCD image sensor is insufficient, an infrared light source can be used as an auxiliary light source.

  The reason why the signal amount of the CCD image sensor is insufficient is that there are restrictions on the camera arrangement, such as the distance between the infrared camera 12 and the human body being long, and the lens diameter of the infrared camera 12 being not sufficiently large. When an infrared light source is used, the ethyl alcohol content A corresponding to the blood alcohol concentration can be obtained by detecting the reflection spectrum characteristics of the infrared light reflected by the human body due to the blood ethyl alcohol.

  The ethyl alcohol detection unit 44 uses the reference received light quantity 52 (= Ith) obtained from the λ1 image 56 stored in the memory 38 and the reference image 50 stored in the nonvolatile memory 36 to correspond to the ethyl alcohol concentration. The ethyl alcohol content A given by the equation (1) is calculated.

  FIG. 4 shows a driver characteristic region extraction image 54 generated by the reference image registration unit 40 of FIG. 1 and used when the ethyl alcohol detection unit 44 calculates the ethyl alcohol content A. In order to detect the concentration of ethyl alcohol in the capillary of the driver 20 from the amount of received infrared light, the capillary on the driver's face appears on the skin surface and the attenuation of the absorption spectrum by ethyl alcohol is sufficiently obtained. It is necessary to specify the location and calculate the ethyl alcohol content A.

  In the case of FIG. 4, in the reference image registration process performed in a normal state in which ethyl alcohol is not present in the blood, the reference image 50 obtained through the λ1 filter is used as a target from the capillaries. Non-volatile memory by generating a feature extraction region 72-1 with thin skin such as lips, which easily emits infrared radiation due to body temperature, and a feature region extraction image 54 in which feature extraction regions 72-2 and 72-3 are set around both eyes 36.

  If the feature area extraction image 54 can be generated for the driver, the reference image registration processing unit 40 sums or averages the pixel values of the feature extraction areas 72-1 to 72-3 set in the feature area extraction image 54. Based on the value, a reference received light amount 52 is obtained.

  Further, the ethyl alcohol detection unit 44 calculates the received light amount I1 of the λ1 image 56 for calculating the ethyl alcohol content A in the equation (1), and the feature extraction regions 72-1 to 72- of the feature region extraction image 54 are calculated. 3 is obtained, and the sum or average value of the pixel values included in 3 is obtained as I1, and Ith, which is the value of the reference received light quantity 52 already stored in the nonvolatile memory 36, is used to calculate the ethyl alcohol content from the above equation (1). A is calculated.

In the equation (1), the division value (I _th / I ₁ ) of the reference light reception amount Ith of the reference image 50 and the light reception amount I1 of the λ1 image 56 is calculated. _th -I ₁ ), square division value (I _th / I ₁ ) ² or square error (I _th -I ₁ ) ² may be calculated.

  Further, in the present embodiment, the disturbance substance detection unit 46 calculates the disturbance degree B from the λ2 image 58 that is picked up by switching the wavelength tunable filter 16 to the wavelength band as the λ2 filter, and the ethyl alcohol detection unit 44 The determination unit 48 determines whether or not the calculated ethyl alcohol content A is appropriate.

For example, when the driver 20 as a subject is a woman, for example, the face to be photographed is covered with makeup, and for example, menthol C ₁₀ H ₂₀ O exists as a substance contained in the cosmetic. However, although there is no ethyl alcohol, an absorption spectrum of λ1 = 2.77 μm exists in the λ1 image 56 for menthol, and the ethyl alcohol content A may be erroneously detected.

That is, menthol C ₁₀ H ₂₀ O contained in cosmetics and the like has absorption spectra at 2.77 μm and 3.37 μm, like ethyl alcohol. In addition to this, the wavelength λ2 = 3.28 μm derived from the menthol benzene shell also has an intrinsic absorption spectrum.

Therefore, in the present embodiment, menthol contained in cosmetics or the like is regarded as a disturbance substance for ethyl alcohol detection, and the same absorption wavelengths λ1 = 2.77 μm and 3.37 μm as those of ethyl alcohol are inherent absorption wavelengths λ2 = 3. The wavelength tunable filter 16 is switched to the wavelength band of the λ2 filter as the second filter that selectively transmits 28 μm, and the received light amount I2 is calculated from the captured image of the infrared radiation that has passed through the λ2 filter, that is, the λ2 image 58. B as a disturbance degree B for determining menthol using the reference received light amount Ith obtained from the reference image 50 from which a received light amount corresponding to an infrared radiation amount from a normal human body in which no alcohol is present in the blood is obtained. = I _th / I ₂ (2)
Is calculated.

  If the degree of disturbance B given by equation (2) is equal to or greater than a predetermined threshold Bth, it can be determined that it is menthol and not ethyl alcohol. The method for determining the threshold value Bth is the same as in the case of the ethyl alcohol content A.

  That is, the disturbance substance detection unit 46 provided in the CPU 26 in FIG. 1 receives the received light amount Ith of the reference image 50 obtained by transmitting through the λ1 filter when ethyl alcohol stored in the nonvolatile memory 36 is not present in the blood. Then, based on the received light amount I2 obtained from the λ2 image 58 obtained through the λ2 filter, the disturbance degree B is calculated according to the equation (2).

  Based on the ethyl alcohol content A detected by the ethyl alcohol detection unit 44 and the disturbance level B detected by the disturbance substance detection unit 46, the determination unit 48 detects a drunk state due to ethyl alcohol detection and methyl alcohol non-detection. Determine the normal state by.

  Specifically, the determination unit 48 determines that the ethyl alcohol is detected when the ethyl alcohol content A is equal to or higher than the predetermined threshold Ath and the disturbance level B is lower than the predetermined threshold Bth, and determines the drunken state. On the other hand, when the ethyl alcohol content A is greater than or equal to the predetermined threshold Ath and the disturbance degree B is also greater than or equal to the predetermined threshold Bth, ethyl alcohol is not ethyl alcohol but menthol contained in a disturbance substance such as cosmetics. Is determined as non-detection, and the normal state is determined.

In addition to menthol, the disturbance substance in the present embodiment is stearic acid C ₁₇ H ₃₅ COOH, which is also used in cosmetics and the like. Stearic acid has absorption spectra at the same wavelengths of 2.77 μm and 3.37 μm as ethyl alcohol, but an absorption spectrum appears at a wavelength of 5.88 μm due to -C00H, which is not in ethyl alcohol.

  Therefore, for stearic acid, the wavelength tunable filter 16 is switched to selectively transmit the wavelength λ3 = 5.88 μm to prepare a λ3 filter as a third filter, and the λ3 image captured by the infrared camera 12 in this state Is stored in the memory 38.

  The processing of the disturbance substance detection unit 46 for the λ3 image corresponding to the absorption spectrum of stearic acid calculates the amount of received light I3 from the λ3 image, and, as in the case of the λ2 image, the disturbance for stearic acid from the equation (2). The degree B is calculated, and if the disturbance degree B is equal to or greater than the predetermined threshold Bth, the determination unit 48 can determine that it is stearic acid and not ethyl alcohol.

Furthermore, in the case of glycerin C ₃ H ₅ (OH) ₃ as a disturbance substance for ethyl alcohol, the wavelength 2.77 μm of the absorption spectrum derived from —CH ₃ does not appear, and therefore glycerin per λ1 image 56 of the λ1 filter, The amount of received light I1 is not attenuated, and it can be confirmed that the alcohol content A calculated by the above equation (1) is not less than ethyl alcohol when it is not less than the predetermined threshold value Ath. Therefore, glycerin is considered as a disturbance substance. There is no need.

  In this embodiment, menthol and stearic acid, which are abundantly contained in cosmetics and the like, are taken as examples of disturbance substances. However, when substances having spectral absorption at the same wavelength as other ethyl alcohol exist, By obtaining an image of a wavelength specific to a wavelength other than the absorption wavelength of ethyl alcohol and obtaining the degree of disturbance, erroneous detection of ethyl alcohol by a disturbance substance can be reliably avoided.

In addition, there are innumerable substances having —CH ₃ and —OH. Among them, menthol and stearic acid contained in cosmetics are exemplified as substances that may be positively attached to the face. In addition, acetoacetate produced in the body of diabetics also has —CH ₃ and —OH, and has the same spectral absorption band as ethanol, but has a third absorption band of 5.83 μm that is not found in ethanol. Can be recognized as a disturbance substance.

  FIG. 5 is a flowchart showing an ethyl alcohol detection process according to the embodiment of FIG. In FIG. 5, first, at step S1, the presence or absence of an ethyl alcohol detection request is checked. For example, when the driver turns the ignition key to the on position to start the engine while sitting on the seat, a detection request signal is output to the ethyl alcohol detection device 10 and the detection process starts. Is done.

  When the detection request is determined in step S1, the process proceeds to step S2, and it is checked whether or not the initial registration of the reference image 50, the reference light reception amount 52, and the feature region extraction image 54 to the nonvolatile memory 36 has been completed.

  When the user uses the delivered vehicle for the first time, the initial registration has not been completed. Therefore, the process proceeds to step S3, and the reference image received light amount registration process is executed by the reference image registration unit 40. Details of the reference image received light amount registration processing in step S3 are shown in the flowchart of FIG.

  On the other hand, if it is determined in step S2 that the initial registration has been completed, the process proceeds to step S4 to check whether it is the update timing. As the update timing, for example, a cycle of one month is set, and the update timing is determined in step S4 every time one month elapses, and the process proceeds to step S3 to perform the registration processing of the reference image light reception amount again, and the registration contents performed last time Will be updated.

  Subsequently, in step S5, the wavelength tunable filter 16 is set to the wavelength band as the λ1 filter, and in step S6, the infrared camera 12 performs a photographing operation to acquire the λ1 image 56 and store it in the memory 38. At this time, if an infrared light source is provided, the infrared light source is turned on, the driver 20 is irradiated with infrared light as an auxiliary, and the λ1 image 56 is acquired and stored by the reflected light.

  Next, in step S7, the wavelength tunable filter 16 is set in a band as a λ2 filter, and the λ2 image 58 is stored in the memory 38 by the photographing operation in step S8.

  The memory storage by capturing the λ1 image and the λ2 image in Steps S5 to S8 may be performed once, or may be performed continuously by capturing the image n times as necessary.

  Subsequently, in step S9, as shown in FIG. 4, the non-volatile memory 36 having the feature extraction regions 72-1 to 72-3 set for locations where heat from the capillary such as the driver's lips and eyes is likely to appear. Is used for the λ1 image 56 and the λ2 image 58 stored in the memory 38, and the received light amount is calculated for the pixels included in the feature regions 72-1 to 72-3. I do.

  First, in step S10, the received light amount I1 is calculated from the λ1 image 56. Next, in step S11, the received light amount I2 is calculated from the λ2 image. Next, in step S12, the alcohol content A is calculated from the equation (1). In step S13, it is checked whether or not the calculated alcohol content A is greater than or equal to the threshold Ath. If the alcohol content A is greater than or equal to the threshold Ath, it is determined that ethyl alcohol is contained in the capillary, and the process proceeds to step S14. On the other hand, when the ethyl alcohol content A is less than the threshold value Ath, there is no spectral absorption due to ethyl alcohol, and the process returns to step S1 as non-detection of ethyl alcohol.

  In step S14 that proceeds when the alcohol content A is equal to or greater than the threshold value Ath, the disturbance degree B is calculated from the equation (2), and in the next step S15, the calculated disturbance degree B is equal to or greater than the threshold value bth. If it is determined that this is the case, it is determined that this is a false detection of the ethyl alcohol content A due to a disturbance substance other than ethyl alcohol, and the process returns to step S1 assuming that the normal state is the ethyl alcohol non-detection state.

  On the other hand, if the disturbance degree B is less than the threshold value Bth in step S15, it is determined that there is no false detection of ethyl alcohol by the disturbance substance, and the process proceeds to step S16, where it is determined that the alcoholic state is detected by the detection of ethyl alcohol. Execute.

  In response to the determination that the person is in a drunken state, in FIG. 1, a warning display that prompts the user to not drive drunkenly is displayed on the display unit 60, a voice message is output, and the ignition key is pressed by the control unit 62. Do not allow drunk driving by, for example, prohibiting the engine from starting even if it is turned to the start position.

  FIG. 6 is a flowchart showing details of the reference image light reception amount registration process in step S3 of FIG. In FIG. 6, in the reference image received light amount registration process, first, in step S <b> 17, guidance for performing the registration process is output using the display unit 60 and the audio output function. This guidance outputs, for example, “Register the driver's reference image. Put your hand on the handle when you are not using cosmetics and face the front.

  Subsequently, in step S18, the wavelength tunable filter 16 is set to the band as the λ1 filter, and in step S19, the imaging operation of the infrared camera 12 is performed, and the λ1 image is stored in the memory 38 used as a work memory.

  Next, in step S20, feature area extraction images in which feature extraction areas 72-1 to 72-3 including the eyes and lips of the driver 20 are set as shown in FIG. 4 for the λ1 image stored in the memory 38. 54 is generated and stored on the memory 38.

  In step S21, the feature region extraction image 54 created in step S20 is set for the λ1 image on the memory 38, and the sum or average value of the pixel values included in the feature extraction regions 72-1 to 72-3 is set. Λ1 image received light amount I1 is calculated.

  Subsequently, a determination process is performed as to whether or not a disturbance substance such as cosmetic menthol exists on the face of the driver to be registered. In this process, the wavelength tunable filter 16 is set in the band as the λ2 filter in step S22, and the λ2 image is stored in the memory 38 used as a work memory by the imaging operation of the infrared camera 12 in step S23.

  Next, in step S24, the feature region extraction image 54 created in step S20 is applied to the λ2 image, and the λ2 image is received as the sum or average value of the pixel values included in the feature extraction regions 72-1 to 72-3. The quantity I2 is calculated.

Next, in step S25, the disturbance degree B is calculated from the default reference received light amount (Ith) ₀ stored in advance in the nonvolatile memory 36 and the λ2 received light amount I2 calculated in step S24, using the equation (2).

  Subsequently, in step S26, if the calculated disturbance degree B is less than the threshold value Bth, the face of the driver who is the object of initial registration is not subjected to makeup, and is an appropriate image for initial registration. In step S27, the λ1 image light reception amount I1 stored in the memory 38 is stored in the nonvolatile memory 36 as the reference light reception amount Ith. Further, in step S28, the λ1 image stored in step S19 and the feature region extracted image obtained in step S20 are stored in the nonvolatile memory 36 as a reference image 50 and a feature region extracted image 54, respectively.

On the other hand, if the disturbance degree B is greater than or equal to the threshold Bth in step S26, makeup is applied to the face of the driver who is the object of initial registration, and an image having an absorption spectrum in the λ1 image having the ethyl alcohol absorption wavelength is displayed. Since the λ1 image light reception amount I1 that is the reference light reception amount is calculated for the target, in this case, an error is determined in step S29, and the default reference light reception amount (Ith) stored in advance in the nonvolatile memory 36 is _0. And the reference received light amount Ith depending on the driver by the registration process is not updated. Also in the case of this error determination, the feature region extraction image 54 is stored in the nonvolatile memory 36 in step S28.

  By the reference image light reception amount registration process as shown in FIG. 6, the reference light reception amount Ith specific to the driver as a reference obtained from the λ1 image in a normal state where ethyl alcohol is not present in the blood can be correctly acquired. Yes, by performing the update process of the reference image light reception amount registration during the subsequent operation, the correct reference light reception amount Ith following the change in the physical condition of the driver can be obtained, and the reliability of the ethyl alcohol detection process is guaranteed. be able to.

In addition, even if the reference image received light amount registration process has failed, the default reference received light amount prepared as the setting value at the manufacturing stage can be used, so compared to the reference received light amount depending on the driver. Although the detection accuracy of ethyl alcohol is somewhat inferior, even if the reference light reception amount registration process fails, basically, the ethyl alcohol detection process can be effectively performed using the default reference light reception amount (Ith) ₀ .

  FIG. 7 is an explanatory diagram showing a filter switching infrared camera using a rotating disk used in place of the wavelength tunable filter of FIG. As in FIG. 2, the infrared camera 12 has a wavelength tunable filter arranged in an optical system having an objective lens 64 and an imaging lens 66, and a CCD image sensor 24 is provided on the camera body side.

  A filter switching unit 74 is disposed in front of the infrared camera 12 in place of the wavelength tunable filter 16 in FIG. 1, and a λ1 filter 76-is used as a filter having a different band, for example, at two places on the rotating disk. 1 and the λ2 filter 76-2 are mounted, and an image of the driver's face by infrared radiation or reflected light is captured while the filters are sequentially switched by a filter driving unit equipped with a motor.

  FIG. 8 is a block diagram showing another embodiment of an ethyl alcohol detector using an infrared sensor. In FIG. 8, the infrared camera 12 provided for the ethyl alcohol detection device 10 is provided with an infrared sensor 78 instead of the CCD image pickup device 24 of FIG.

  FIG. 9 shows the infrared sensor 78 of FIG. The infrared sensor 78 has a window 92 made of glass or the like at the opening of the case 90, and an infrared detection element 94 is provided inside the window 92 as shown in a transparent state. The infrared detection element 94 is attached to an external lead 96. It is connected.

  As the infrared detection element 94, an uncooled element such as a pyroelectric element, a thermopile, a thermistor, or a bolometer can be used. A cooling element such as MCT or Insb may be used.

  Referring to FIG. 8 again, along with the provision of the infrared sensor 78 in the infrared camera 12, a sensor light reception control unit 77 is provided instead of the camera control unit 14 in FIG. 18 is operated, and a band is set in the wavelength tunable filter 16.

  The CPU 26 of the ethyl alcohol detection device 10 is provided with a reference light reception signal registration unit 80 and a light reception control unit 82 corresponding to the infrared sensor 78. The ethyl alcohol detection unit 44, the disturbance substance detection unit 46, and the determination unit 48 provided in the CPU 26 are the same as those in FIG.

  The reference light reception signal registration unit 80 operates when the vehicle is first used, and the filter driving unit 18 is operated by the light reception control unit 77 so that the wavelength tunable filter 16 is λ1 = 2. The light reception signal detected by the infrared sensor 78 of the infrared camera 12 in a state where the λ1 filter including 77 μm is set is stored in the nonvolatile memory 36 as a reference light reception signal 84 (value is Ith).

  The light reception control unit 82 stores the λ1 light reception signal 86 detected by the infrared sensor 78 of the infrared camera 12 in the memory 38 with the wavelength variable filter 16 set to the λ1 filter. Further, the λ2 light reception signal 88 obtained by the infrared sensor 78 is stored in the memory 38 with the wavelength tunable filter 16 set to the λ2 filter.

  That is, when the infrared sensor 78 is used, I1 as the λ1 received light amount 86 and I2 as the λ2 received light amount 88 are obtained directly in the memory 38 by the light receiving control accompanying the switching of the filter band by the wavelength tunable filter 16. be able to.

  For this reason, the ethyl alcohol detection unit 44 uses the reference light reception signal Ith stored in advance in the nonvolatile memory 36 and the λ1 light reception amount I1 stored in the memory 38 to determine the ethyl alcohol content according to the above equation (1). A is calculated. The disturbance substance detection unit 46 calculates the disturbance degree B from the reference light reception signal Ith stored in the nonvolatile memory 36 and the λ2 light reception signal I2 stored in the memory 38 by the above equation (2), and finally From the ethyl alcohol content A and the disturbance B, the determination unit 48 can determine whether or not ethyl alcohol is detected.

  FIG. 10 is a flowchart showing the ethyl alcohol detection process according to the embodiment of FIG. In FIG. 10, when the detection request is determined in step S31, it is checked in step S32 whether or not the initial registration has been completed. If the initial registration has not been completed, the process proceeds to step S33 to execute the reference light reception signal registration process. Details of the reference light reception signal registration processing are shown in the flowchart of FIG.

  If the initial registration has been completed in step S32, it is checked in step S34 whether or not it is an update timing. For example, if it is an update timing of one month cycle, the reference light reception signal registration process is executed again in step S33. Then, the reference light reception signal is updated. If it is not the update timing, the process of step S33 is skipped.

  Next, in step S35, the wavelength tunable filter 16 is set to the λ1 filter, and in step S36, the λ1 light reception signal I1 is acquired from the infrared sensor 78 of the infrared camera 12 and stored in the memory 38. Next, in step S37, the wavelength tunable filter 16 is set to the λ2 filter, and in step S38, the λ2 light reception signal I2 is acquired from the infrared sensor 78 and stored in the memory 38.

  Next, in step S39, the ethyl alcohol content A is calculated by the equation (1). Next, if the content A is less than the threshold value Ath in step S40, ethyl alcohol is not detected, and the process returns to step S31. If the content A is equal to or greater than the threshold Ath, the process proceeds to step S41, and the disturbance degree B1 is calculated by the above equation (2).

  Next, if the disturbance degree B is greater than or equal to the threshold value Bth in step S42, it is not the alcohol content A due to ethyl alcohol but the alcohol content A due to a disturbance substance such as menthol, so that the process returns to step S31 as non-detection of ethyl alcohol. If the disturbance level is less than the threshold value bth in step S42, it is determined that ethyl alcohol has been detected, and in step S43, it is determined that the state is drunk, and corresponding processing is performed.

  FIG. 11 is a flowchart showing details of the reference light reception signal registration process in step S33 of FIG. In FIG. 11, the reference light reception signal registration process is performed in step S44 after the display or voice guidance for performing the reference light reception signal registration process to the driver, and then in step S45, the wavelength tunable filter 16 is set to the λ1 filter. In step S46, the λ1 light reception signal I1 from the infrared sensor 78 is acquired and stored in the memory 38 as a work memory.

  In step S47, the wavelength tunable filter 16 is set to the λ2 filter. In step S48, the λ2 light reception signal I2 is acquired from the infrared sensor 78 and stored in the memory 38 as a work memory. Next, in step S49, the disturbance degree B is calculated by the above (2) using the default reference light receiving signal Ith stored in advance in the nonvolatile memory 36.

  Next, when the disturbance degree B is less than the strong base Bth in step S50, the driver is in a state suitable for the reference light reception signal registration process in which makeup is not applied, and is stored in the memory 38 in step S51. In step S46, the λ1 light reception signal I1 is stored in the nonvolatile memory 36 as the reference light reception signal Ith.

On the other hand, if the disturbance degree B is equal to or greater than the threshold value Bth in step S50, makeup is applied to the driver's face to be registered, and the ethyl alcohol absorption spectrum is generated by the disturbance substance. In step S52, an error is determined. In step S53, the default reference light reception signal (Ith) ₀ stored in advance in the nonvolatile memory 36 is validated. When returning to the main routine of FIG. 10, the default reference light reception signal is used. The ethyl alcohol content A and disturbance degree B can be calculated.

  As described above, even when the infrared sensor is used for the infrared camera 12, the reference light receiving signal Ith used for the calculation of the ethyl alcohol content A and the disturbance B is the infrared ray emitted from the face of the driver 20 or an infrared light source. It is possible to set based on the actual received light signal of the reflected infrared rays, and the system for the ethyl alcohol detection process can be enhanced by using the reference received light signal depending on the driver.

  FIG. 12 is a block diagram showing another embodiment of an ethyl alcohol detector using a multi-infrared sensor. In FIG. 12, the infrared camera 12 is provided with a multi-infrared sensor 98 following the optical system 22.

  FIG. 13 shows the multi-infrared sensor 98 of FIG. In the multi-infrared sensor 98, four infrared detecting elements 94-1 to 94-4 are arranged in this embodiment as shown transparently inside a case 90 provided with a window 92 on the light receiving side. .

  For this reason, when an image of the subject as the driver is formed on the multi-infrared sensor 98, the infrared detection elements 94-1 to 94-94 are divided into four regions divided into the subject image, that is, the image of the driver's face. -4 is obtained. Therefore, the λ1 received light amount I1 and the λ2 received light amount I2 can be obtained by calculating the sum or average value of the received light signals obtained from the four divided infrared detecting elements 94-1 to 94-4.

  Further, in the registration process by the reference light reception signal registration unit 100, by calculating the sum or average value of the four light reception signals obtained from the four divided infrared detection elements 94-1 to 94-4, The obtained λ1 received light amount I1 is set as a reference received light amount Ith. This process is performed by the reference light reception signal registration unit 100 and the light reception control unit 102 provided in the CPU 26 of FIG. The other configuration is the same as that of the embodiment using the single infrared detection element shown in FIG.

  FIG. 14 is a flowchart showing an ethyl alcohol detection process according to the embodiment of FIG. In FIG. 14, steps S54 to S57 are the same as steps S31 to S34 of FIG. Steps S64 to S68 in FIG. 14 are the same as steps S39 to S43 in FIG.

  The difference is that in steps S58 to S63 of FIG. 14, the received light amount is calculated from the received light signals of the four infrared detecting elements 94-1 to 94-4 shown in FIG. That is, in step S58, the wavelength tunable filter 16 is set to the λ1 filter, and in step S58, the λ1 light reception signal group 106 including four light reception signals is acquired from the infrared detection elements 94-1 to 94-4 of the multi-infrared sensor 98. Save to memory 38.

  Next, in step S60, the wavelength tunable filter 16 is set to the λ2 filter, and the λ2 received light signal group 108 including the four received light signals from the infrared detecting elements 94-1 to 94-4 of the multi-infrared sensor 98 is acquired and stored in the memory 38. Save to.

  Next, in step S62, the received light amount I1 is calculated as the sum or average value of the four received light signals from the λ1 received light signal group 106, and similarly received in step S63 as the sum or average value from the four signals of the λ2 received light signal group 108. The quantity I2 is calculated.

  As described above, for example, by using the multi-infrared sensor 98 including the four infrared detection elements 94-1 to 94-4, the λ1 received light signal group 106 and the λ2 received light signal group 108 are obtained from the sum or average value of a plurality of received light signals. By obtaining, the infrared detection sensitivity and resolution can be increased as compared with the case where the single infrared detection element 94 of FIG. 9 is used. Note that the number of infrared detection elements may be increased to 8 elements, 16 elements, and 32 elements as necessary in addition to the four elements.

  FIG. 15 is a flowchart showing details of the reference light reception signal registration process in step S56 of FIG. This reference received light signal registration process includes steps S69 to S80, which are basically the same as those in the case of the single infrared detecting element 94 shown in FIG. 11, but are applied to the wavelength tunable filter 16 as in steps S70 to S72. The λ1 filter is set, the λ1 received light signal group including a plurality of received light signals is acquired and stored in the work memory, and then the λ1 received light signal I1 is calculated from the λ1 received light signal group, and the wavelength in steps S73 to S75. A difference is that a λ2 filter is set in the variable filter 16, a λ2 light reception signal including a plurality of light reception signals is acquired, and a λ2 light reception amount I2 is calculated therefrom.

  FIG. 16 is a block diagram showing another embodiment of an ethyl alcohol detection device using a multi-infrared sensor with a built-in filter. The infrared camera 12 is provided with a multi-infrared sensor 112 incorporating a filter following the optical system 22.

  FIG. 17 shows the internal structure of the multi-infrared sensor 112 shown in FIG. In the multi-infrared sensor 112, for example, three infrared light receiving elements 94-1 to 94-3 are arranged in a case 90 having a window 92 on the light receiving side, and a λ1 filter 126-1, a λ2 filter 126-2, and A λ3 filter 126-3 is arranged.

  The λ1 filter 126-1 is a filter that transmits the spectral absorption wavelength λ1 = 2.77 μm of ethyl alcohol. The λ2 filter 126-2 is a filter that transmits a wavelength λ2 = 3.28 μm unique to menthol, which is a disturbance substance. Further, the λ3 filter 126-3 is a filter that transmits the wavelength λ3 = 5.88 μm that is unique to stearic acid, which is a disturbance substance.

  In this way, according to the multi-infrared sensor 112 in which the filter and the infrared light receiving element are combined corresponding to 1: 1, the filter control by the wavelength variable filter 16 as shown in the embodiment of FIGS. The infrared sensor 112 itself can directly detect the received light signals corresponding to the wavelengths λ1, λ2, and λ3, and the apparatus configuration can be simplified correspondingly, and the processing by the CPU 26 can be simplified to reduce the processing load. it can.

  FIG. 18 is a flowchart showing ethyl alcohol detection processing according to the embodiment of FIG. In FIG. 18, steps S81 to S83 are the same as steps S54 to S56 of FIG. In the next steps S85 to S87, since the multi-infrared sensor 112 itself has a built-in filter as shown in FIG. 17 without providing the wavelength variable filter, the λ1 light reception signal I1 and the λ2 light reception signal I2 are directly provided. Further, the λ3 light reception signal I3 can be acquired and stored in the memory 38.

  Subsequently, the alcohol content A is calculated in step S88. If the content A is greater than or equal to the threshold Ath in step S89, the disturbance B1 is calculated in step S90. If the disturbance B1 is less than the threshold Bth in step S91. In step S92, the disturbance level B2 is calculated. In step S93, if the disturbance level B2 is less than the threshold value Bth, it is determined that alcohol has been detected, and in step S94, the drunk driving is determined and corresponding processing is performed.

  FIG. 19 is a flowchart showing details of the reference light reception signal registration process in step S83 of FIG. In this reference light reception signal registration processing, guidance for registration processing is performed in step S95, and then in steps S96 and S97, the λ1 filter 126-1 and the λ2 filter 126-2 of the multi-infrared sensor 112 are supported. The λ1 light reception signal I1 and the λ2 light reception signal I2 are acquired directly from the infrared detection elements 94-1 and 94-2 and stored in the memory 38 as a work memory.

Subsequently, in step S98, the disturbance degree B is calculated from the equation (2) using the default reference light reception signal Ith and the λ2 light reception signal I2. If the disturbance degree B is less than the threshold value Bth in step S99, the process proceeds to step S100. Since there is no influence by disturbance substances, the λ1 light reception signal is stored in the nonvolatile memory 36 as the reference light reception signal Ith. If the disturbance degree B is greater than or equal to the threshold value Bth in step S99, it is determined that there is an error in step S101, the default reference received light signal (Ith) ₀ is validated in step S102, and the process returns to the main routine of FIG.

  In addition, although said embodiment took filter switching by the wavelength variable filter and the mechanical filter switching unit as an example, in addition to this, by the spectroscope using an analysis grating etc., the target spectral band is obtained. You may make it measure an image or received light quantity.

Further, the present invention includes appropriate modifications that do not impair the object and advantages thereof, and is not limited by the numerical values shown in the above embodiments.

10: Ethyl alcohol detection device 12: Infrared camera 14: Camera control unit 16: Wavelength variable filter 18: Filter drive unit 20: Driver 22: Optical system 24: CCD image pickup device 26: CPU
28: Bus 30, 32, 34: IF
36: Non-volatile memory 38: Memory 40: Reference image registration unit 42: Imaging control unit 44: Ethyl alcohol detection unit 46: Disturbing substance detection unit 48: Determination unit 50: Reference image 52: Reference received light amount 54: Feature region extraction image 56 : Λ1 image 58: λ2 image 60: Display unit 62: Control unit 64: Objective lens 66: Imaging lens 72-1 to 72-3: Feature extraction region 74: Filter switching unit 76-1, 126-1: λ1 filter 76-2, 126-2: λ2 filter 77: sensor light reception control unit 78: infrared sensors 80, 100, 114: reference light reception signal registration processing units 82, 102, 116: light reception control units 84, 104: reference light reception signal 86: λ1 light reception signal 88: λ2 light reception signal 90: Case 92: Window 94, 94-1 to 94-3: Infrared detector 96: Lead 98, 112: Multi-infrared Sensor 106 and 120: .lambda.1 received signal group 108,122: λ2 received signal group 124: [lambda] 3 light reception signal group 126-3: [lambda] 3 filter

Claims (9)

An image sensor having sensitivity in the infrared wavelength band;
An optical system for forming a subject image on the image sensor;
A first filter that selectively transmits infrared light in a first wavelength band including the absorption wavelength of ethyl alcohol from the subject;
Infrared light in a second wavelength band including other absorption wavelengths of disturbance substances having an absorption wavelength in the same first wavelength body region as the ethyl alcohol from the subject and including a wavelength that is not the absorption wavelength of ethyl alcohol. A second filter that selectively transmits;
Imaging control for imaging the first subject image formed through the first filter and the second subject image formed through the second filter by the imaging device and storing them in a memory And
A reference image registration unit that stores a first subject image formed through the first filter by the imaging control unit as a reference image in a nonvolatile memory when setting a registration mode;
An ethyl alcohol detector that calculates an ethyl alcohol content corresponding to the ethyl alcohol concentration based on a first subject image in the memory and a reference image in the nonvolatile memory;
A disturbance substance detecting unit that calculates a disturbance degree corresponding to the concentration of the disturbance substance based on a second subject image stored in the memory and a reference image of the nonvolatile memory;
A determination unit that determines the detection of the ethyl alcohol based on the ethyl alcohol content and the disturbance level;
An ethyl alcohol detector characterized by comprising:
In the ethyl alcohol detection device according to claim 1,
The first filter selectively transmits infrared light in a wavelength band including 2.77 μm or 3.37 μm as a first wavelength band;
The second filter selectively transmits infrared light in a wavelength band including 3.28 μm as the second wavelength band when the disturbance substance is menthol, and when the disturbance substance is stearic acid, the second filter An ethyl alcohol detection device that selectively transmits infrared light in a wavelength band including 5.88 μm as a wavelength band.
In the ethyl alcohol detection device according to claim 1,
The reference image registration unit calculates a reference received light amount as a sum or an average value of the pixels constituting the reference image and stores it in the nonvolatile memory,
The ethyl alcohol detection unit calculates the ethyl alcohol content based on a first subject received light amount calculated as a sum or an average value of pixel values of the first subject image and a reference received light amount of the nonvolatile memory,
The disturbance substance detection unit calculates the disturbance degree based on a second subject received light amount calculated as a sum or an average value of pixel values of the second subject image and a reference received light amount of the nonvolatile memory. An ethyl alcohol detector.
In the ethyl alcohol detection device according to claim 3,
The ethyl alcohol detection unit is configured to determine whether the ethyl alcohol content is a subtraction value or a division value of a reference light reception amount with the first subject light reception amount, a subtraction value or a division value multiplied by a predetermined coefficient, or a sum of square error values, or Calculated as an average,
The disturbance substance detection unit is configured to calculate the disturbance degree by subtracting or dividing a reference received light amount from the second subject received light amount, a subtracted value or divided value multiplied by a predetermined coefficient, or a sum or average value of square error values. An ethyl alcohol detection device, characterized by:
An infrared sensor comprising one or more infrared light receiving elements;
An optical system for forming a subject image on the infrared light receiving sensor;
A first filter that selectively transmits infrared light in a first wavelength band including the absorption wavelength of ethyl alcohol from the subject;
Infrared light in a second wavelength band including other absorption wavelengths of disturbance substances having an absorption wavelength in the same first wavelength body region as the ethyl alcohol from the subject and including a wavelength that is not the absorption wavelength of ethyl alcohol. A second filter that selectively transmits;
The infrared sensor detects a first light reception signal of a subject received through the first filter and a second light reception signal of a subject received through the second filter, and stores the received light in a memory. A control unit;
A reference light reception signal registration unit that stores and holds the first light reception signal received through the first filter by the light reception control unit as a reference light reception signal when the registration mode is set;
An ethyl alcohol detector that calculates an ethyl alcohol content corresponding to the ethyl alcohol concentration based on the first light reception signal of the memory and the reference light reception signal of the nonvolatile memory;
A disturbance substance detection unit that calculates a disturbance degree corresponding to the concentration of the disturbance substance based on the second light reception signal of the memory and the reference light reception signal of the nonvolatile memory;
A determination unit that determines the detection of the ethyl alcohol based on the ethyl alcohol content and the disturbance level;
An ethyl alcohol detector characterized by comprising:
In the ethyl alcohol detection device according to claim 5,
The first filter selectively transmits infrared light in a wavelength band including 2.77 μm or 3.37 μm as a first wavelength band;
The second filter selectively transmits infrared light in a wavelength band including 3.28 μm as the second wavelength band when the disturbance substance is menthol, and when the disturbance substance is stearic acid, the second filter An ethyl alcohol detection device that selectively transmits infrared light in a wavelength band including 5.88 μm as a wavelength band.
In the ethyl alcohol detection device according to claim 5,
The ethyl alcohol detection unit calculates the ethyl alcohol content based on a first subject light reception signal of the memory and a reference light reception signal of the nonvolatile memory,
The said disturbance substance detection part calculates the said disturbance degree based on the 2nd subject light reception signal of the said memory, and the reference | standard light reception signal of the said non-volatile memory, The ethyl alcohol detection apparatus characterized by the above-mentioned.
In the ethyl alcohol detection device according to claim 7,
The ethyl alcohol detection unit is configured to determine whether the ethyl alcohol content is a subtraction value or a division value of a reference light reception signal with respect to the first subject light reception signal, a subtraction value or a division value multiplied by a predetermined coefficient, or a sum of square error values or Calculated as an average,
The disturbance substance detection unit is configured such that the disturbance degree is a subtraction value or division value of a reference light reception signal with respect to the second subject light reception signal, a subtraction value or division value multiplied by a predetermined coefficient, or a sum or average value of square error values. An ethyl alcohol detection device, characterized by:
  6. The ethyl alcohol detection device according to claim 5, wherein the infrared sensor is configured by combining a first filter, each of one or a plurality of second filters, and an infrared light receiving element in a sensor housing. An ethyl alcohol detector.

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