Device and method for detecting the blood-alcohol content, bac, of a person

Abstract

The invention relates to a method for determining the blood-alcohol content, BAC, of a person in a vehicle (1), comprising the steps of: recording one or more images of the person in the vehicle (1) by means of one or more imaging units (2) arranged in the vehicle; analysing the images by means of a data-processing unit (3) and determining body data and facial data using a database (5); calculating, from the facial data, three-dimensional target vectors V1 and / or V2 of the mouth and / or the nose of the person with respect to an air-alcohol-measuring instrument (4) arranged in the vehicle (1), in particular an infrared laser spectrometer designed for directional and contactless measuring; activating the air-alcohol-measuring instrument (4) and measuring the breath alcohol content BRAC of the person in the region of the mouth and / or nose, taking into account the target vectors V1 and / or V2; and calculating a correction factor K taking into account the body data, in particular the sex, the weight, the age and / or the height of the person; and determining the blood-alcohol content BAC = K * BRAC.

Description

[0001] Device and method for detecting the blood alcohol content BAC of a person

[0002] The invention relates to a device and a method for detecting the blood alcohol content BAC of a person.

[0003] A person's alcohol level can be measured by the blood alcohol concentration (BAC) and the breath alcohol concentration (BRAC). This is particularly relevant for determining a driver's alcohol level.

[0004] The actual impairment of a person due to alcohol can only be reliably determined from the BAC value, but the BRAC value can be determined much more easily and, above all, non-invasively. The BAC value can be approximately calculated from the BRAC value, given various human data.

[0005] The BRAC value can be measured using analyzers that directly contact the person's mouth, allowing the person's breath to flow directly into the analyzer. However, there are also contactless analyzers that do not need to be placed directly next to the person's mouth. With these, the measurement is usually performed using a directed infrared laser spectrometer. Such analyzers are also suitable for measuring the BRAC of a driver. However, to accurately determine the BAC value from the measured BRAC value, a variety of other driver data must be taken into account. Another problem with using contactless analyzers is that there is no certainty as to whether the person is using the analyzer correctly and whether the conditions for a valid measurement are even met.

[0006] The object of the invention is therefore to provide a method and a device for detecting the alcohol intoxication of a vehicle driver, which allows the use of a contactless analysis device for measuring the alcohol concentration in the breath of the vehicle driver BRAC, and yet provides an accurate and reliable estimate of the alcohol concentration in the blood of the vehicle driver BAC.

[0007] These and other objects are achieved according to the invention by a method and a device according to one of the independent patent claims.

[0008] A method according to the invention for determining the blood alcohol content of a person in a vehicle comprises the following steps.

[0009] First, a 2D or 3D image capture unit located in the vehicle captures one or more images or videos of the person in the vehicle, in particular the driver. The image capture unit can be configured, in particular, as a 3D camera.

[0010] A data processing unit arranged in the vehicle determines a plurality of body data of the person from the image or video. To determine the body data from the images, the data processing unit can use an abstracted body data model, preferably in the form of a graph, and compare the body data model with a plurality of reference models taken from the database. The body data model can include the positions of defined key points, such as the wrist, arm joint, sternum, shoulder joint, knee joint, elbow joint, hip joint, or head center, as well as the distances between these key points. The body data determined by the data processing unit can be at least the height, body weight, age, and / or gender of the person. The data processing unit also determines a plurality of facial data of the person.To determine the facial data from the images, the data processing unit can determine an abstracted facial data model, preferably in the form of a graph, and compare the facial data model with a plurality of reference models taken from the database. The facial data model can include the positions of defined key points, such as the nose, corners of the mouth, upper lip, lower lip, forehead, eyes, ears, and chin, as well as the distances between these key points. The facial data determined by the data processing unit can include at least the three-dimensional position of the nose, the mouth, the opening state of the mouth, and the gaze direction vector BV of the person's head relative to an internal vehicle coordinate system, in particular relative to an air-alcohol measuring device arranged in the vehicle. Furthermore, it can be detected whether the person is wearing a mask covering the mouth and / or nose.

[0011] To determine the body data and / or facial data, a matching algorithm or a classification method from the field of machine learning can be applied, in particular a neural network trained with reference images. However, predetermined heuristics can also be applied, for example, the distance between the person's detected upper and lower lips to determine the opening state of the mouth.

[0012] The data processing unit calculates from the facial data three-dimensional target vectors Vi and / or V2 of the person's mouth and / or nose relative to an air alcohol measuring device arranged in the vehicle, in particular an infrared laser spectrometer designed for directed and contactless measurement.

[0013] The target vectors V1 and V2 denote the three-dimensional distance and angle between the detected position of the mouth and the detected position of the nose and the known position of an air alcohol measuring device located in the vehicle.

[0014] The air alcohol measuring device is designed to detect the alcohol in the air at a specific three-dimensional distance and angle from the measuring device, for example, using a targeted infrared laser spectrometer. Such laser spectrometers are based on the absorption of laser light by specific molecules to be detected as the light passes through a gas sample. By analyzing the absorption spectrum, the ethanol or alcohol content in a gas sample can be determined.

[0015] The data processing unit then activates the air alcohol detector and initiates the measurement of the person's breath alcohol concentration (BRAC) at the positions determined by the target vectors. The distance and angle to the driver's mouth and nose (target vectors V1 and V2) are thus transmitted to the air alcohol detector, and infrared laser spectroscopy measurements of the gas sample are performed at the three-dimensional position of the driver's mouth and nose to determine the local BRAC value.

[0016] Finally, the data processing unit calculates a correction factor K, taking into account the person's physical data, in particular the person's gender, weight, age, and / or height, and determines the blood alcohol content, namely the estimated amount of alcohol in grams in the person's blood. For this purpose, the measured BRAC value is multiplied by a standard correction factor K, so that BAC = K * BRAC.

[0017] The value of K depends on the measured body data. Various calculation models are available in the literature. In particular, the so-called Widmark formula can be used. This distinguishes between men and women and is as follows: BAC for men = Amount of alcohol consumed in grams / (body weight in kilograms x 0.68) and BAC for women = Amount of alcohol consumed in grams / (body weight in kilograms x 0.55). The standard correction factor K is therefore K = 1 / (body weight in kilograms x 0.68) for men and K = 1 / (body weight in kilograms x 0.55) for women. The standard correction factor K is usually in the range of 0.01 - 0.05.

[0018] Additional calculation models are available in the literature that incorporate the person's age or height into the correction factor in addition to body weight and gender. For example, the value of K can be increased if the driver is determined to be younger, for example, under 30 years old, and decreased if the driver is determined to be older, for example, over 30 years old. Likewise, the value of K can be decreased for tall people, for example, over 180 cm, and increased for short people, for example, under 180 cm.

[0019] According to the invention, it can further be provided that the standard correction factor K is expanded by a confidence value A, so that the data processing unit calculates the value BAC = K * A * BRAC. The confidence value A reflects the accuracy of the measurement conditions and can depend, for example, on the determined position of the mouth and nose and the person's gaze direction vector BV.

[0020] According to the invention, it can be provided that the air alcohol measuring device is activated taking facial data into account. For example, it can be provided that the air alcohol measuring device is not activated if it has been determined that the person's mouth is not open or only slightly open, the person is wearing a mask or the mouth is covered in some other way, or if it has been determined that the person's head is not directed toward the air alcohol measuring device.

[0021] According to the invention, the data processing unit can also determine environmental data during operation using one or more image recording units and activate or deactivate the air alcohol measuring device based on the environmental data. The environmental data can be determined by querying systems located in the vehicle, whereby the environmental data can include, for example, the person's driving time, the current time, the lighting conditions, the humidity, or the opening status of the vehicle windows.

[0022] According to the invention, the data processing unit can only activate the air alcohol measuring device when predetermined conditions of the environmental data are met, for example, a predetermined opening state of the vehicle windows is reached. Different activities of the people in the vehicle can also be analyzed and detected. For example, the system can determine when people are eating and drinking, or the system can determine whether alcohol is being consumed based on previously defined properties of the containers and bottles used for eating and drinking.For this purpose, the data processing unit can continuously detect whether the person is consuming food or drinks by regularly activating the image recording units and can only activate the air alcohol measuring device when a predetermined period of time has elapsed after the consumption of food or drinks, for example a period of 15 minutes.

[0023] Such predetermined rules can be regularly reviewed by the data processing unit and prevent measurements under unfavorable conditions. This drastically minimizes the number of invalid measurements and thus also increases the accuracy of the measurement systems. The data processing unit can be configured to activate a warning unit in the vehicle if these predetermined environmental data are not met. The warning unit can also be activated if the measured BRAC value or the calculated BAC value exceeds a predetermined value in one or, if necessary, several consecutive measurements. In this case, vehicle operation can also be prevented.

[0024] The invention further relates to a computer-readable storage medium comprising instructions that cause a data processing unit to execute a method according to the invention.

[0025] The invention further relates to a device for determining the blood alcohol content (BAC) of a person in a vehicle, comprising an image acquisition unit, a data processing unit, an air alcohol measuring device, and a database, wherein the device is configured to carry out a method according to the invention. Such a device comprises a 2D or 3D image acquisition unit configured to acquire one or more images of a person in the vehicle and transmit them to a data processing unit.

[0026] The data processing unit is designed to analyze the captured images and, using a database, to determine the person's body data and facial data.

[0027] Furthermore, the data processing unit is designed to calculate from the facial data three-dimensional target vectors V1 and / or V2 from the mouth and / or nose of the person to an air alcohol measuring device arranged in the vehicle, in particular an infrared laser spectrometer designed for directed and contactless measurement.

[0028] The data processing unit is further configured to activate the air alcohol measuring device so that the person's breath alcohol content BRAC can be measured in the area of ​​the mouth and / or nose, taking into account the target vectors V1 and / or V2.

[0029] Furthermore, the data processing unit is configured to calculate a correction factor K taking into account the person's physical data, in particular the person's gender, weight, age, and / or height. Finally, the data processing unit is configured to calculate the blood alcohol content (BAC) using the formula BAC = K * BRAC.

[0030] Optionally, the data processing unit can be configured to calculate the blood alcohol content (BAC) using the formula BAC = K * A * BRAC, where the value A represents a confidence value that determines the accuracy of the measurement, taking into account the facial data, in particular the opening state of the mouth and the gaze direction vector BV of the person's head. Further features of the invention emerge from the patent claims, the description of the exemplary embodiment, and the figures. They show:

[0031] Fig. 1 is a schematic representation of a device for determining the BAC using cameras in a vehicle;

[0032] Fig. 2 is a schematic representation of a photo taken by an image recording unit in a vehicle.

[0033] Fig. 1 shows a schematic representation of a device for determining the alcohol content of a driver in a vehicle 1 using the method according to the invention. The device comprises an image recording unit 2 in the form of a 3D camera, a data processing unit 3 in the form of a computer, an air alcohol measuring device 4 in the form of an infrared laser spectrometer designed for directed and contactless measurement, and a database 5. Furthermore, the three-dimensional target vectors Vi and V2 calculated by the data processing unit 3, which extend from the air alcohol measuring device 4 to the mouth and nose of the vehicle driver, are schematically shown. The air alcohol measuring device 4 can use these target vectors to specifically determine the air alcohol content in the area of ​​the mouth and nose of the vehicle driver.

[0034] Fig. 2 shows a schematic representation of a photograph taken by an image acquisition unit 2 in a vehicle 1. Shown are again the three-dimensional target vectors V1 and V2 calculated by the data processing unit 3, which extend from the air alcohol measuring device 4 to the mouth and nose of the driver.

[0035] Furthermore, the facial data models determined by the data processing unit 3 are displayed in the form of graphs for the driver and the passenger. The facial data models include key points such as the upper lip, lower lip, nose, and eyes. From the facial data models, the data processing unit 3 calculates a gaze direction vector BV of the respective person relative to an internal vehicle coordinate system. In one embodiment of the method according to the invention, in a first step, the image recording unit 2 arranged in the vehicle 1 takes an image of the persons in the vehicle 1.

[0036] The data processing unit 3 determines body data and facial data of the vehicle driver using an internal vehicle database 5.

[0037] From the facial data, the data processing unit 3 calculates three-dimensional target vectors Vi and V2 from the mouth and nose of the person to an air alcohol measuring device 4 arranged in the vehicle 1, which is an infrared laser spectrometer designed for directed and contactless measurement.

[0038] The data processing unit 3 then activates the air alcohol measuring device 4 so that the person's breath alcohol content BRAC is measured in the area of ​​the mouth and nose, taking into account the target vectors V1 and V2.

[0039] The data processing unit 3 corrects the measured BRAC value to obtain an estimate of the blood alcohol content by multiplying the BRAC value by a correction factor K. The correction factor K is taken from the database 5 and increased or decreased taking into account the body data and the facial data of the driver.

[0040] However, the invention is not limited to the exemplary embodiment outlined here, but encompasses all methods and devices within the scope of the following patent claims.

Claims

Patent claims 1. Method for determining the blood alcohol content BAC of a person in a vehicle (1), comprising the steps of a. recording, by one or more image recording units (2) arranged in the vehicle (1), one or more images of the person in the vehicle (1), b. analysis of the images by a data processing unit (3) and determination, using a database (5), of body data and facial data, c. calculation, from the facial data, of three-dimensional target vectors Vi and / or V2 from the mouth and / or nose of the person to an air alcohol measuring device (4) arranged in the vehicle (1), in particular an infrared laser spectrometer designed for directed and contactless measurement, d. activation of the air alcohol measuring device (4) and measurement of the breath alcohol content BRAC of the person in the region of the mouth and / or nose, taking into account the target vectors V1 and / or V2, e.Calculation of a correction factor K taking into account the physical data, in particular the sex, weight, age and / or height of the person, and determination of the blood alcohol content BAC = K * BRAC.

2. Method according to claim 1, characterized in that the data processing unit (3) determines an abstracted body data model, preferably in the form of a graph, for determining the body data from the images and compares the body data model with a plurality of reference models taken from the database (5).

3. Method according to claim 2, characterized in that the body data model comprises the positions of defined key points, such as wrist, arm joint, sternum, shoulder joint, knee joint, elbow joint, hip joint, or head center, as well as the distances between these key points.

4. Method according to one of claims 1 to 3, characterized in that the body data determined by the data processing unit (3) are at least the body height, the body weight, the age and / or the sex of the person.

5. Method according to one of claims 1 to 4, characterized in that the data processing unit (3) determines an abstracted facial data model, preferably in the form of a graph, for determining the facial data from the images and compares the facial data model with a plurality of reference models taken from the database (5).

6. The method according to claim 5, characterized in that the facial data model includes the positions of defined key points, such as nose, corners of the mouth, upper lip, lower lip, forehead, eyes, ears and chin, as well as the distances between these key points.

7. Method according to one of claims 1 to 6, characterized in that the facial data determined by the data processing unit (3) are at least the three-dimensional position of the nose, the mouth, the opening state of the mouth and the gaze direction vector BV of the person's head relative to a vehicle-internal coordinate system.

8. Method according to one of claims 1 to 7, characterized in that the data processing unit (3) calculates the blood alcohol content BAC taking into account a confidence value A as BAC = K * A * BRAC, wherein the confidence value A is determined taking into account the facial data, in particular taking into account the opening state of the mouth and the gaze direction vector BV of the person's head.

9. The method according to claim 8, characterized in that the data processing unit (3) determines environmental data and increases or decreases the confidence value A also taking into account the environmental data.

10. Method according to claim 9, characterized in that the environmental data are determined by querying systems located in the vehicle (1), the environmental data being, for example, the travel time of the person, the current time, or the opening state of the vehicle windows.

11. Method according to claim 9 or 10, characterized in that the data processing unit (3) activates the air alcohol measuring device (4) only when a. predetermined conditions of the environmental data are met, for example a predetermined opening state of the windows of the vehicle (1) is reached, and / or b. predetermined conditions of the facial data are met, for example the opening state of the mouth or the gaze direction vector BV of the person.

12. Method according to one of claims 9 to 11, characterized in that the data processing unit (3) continuously detects whether the person is consuming food or drinks by regularly activating the image recording units (2), and only activates the air alcohol measuring device (4) when a predetermined period of time has elapsed after the consumption of food or drinks, for example a period of 15 minutes.

13. Method according to one of claims 1 to 12, characterized in that the data processing unit (3) activates a warning unit in the vehicle (1) or blocks the operation of the vehicle (1) if the measured BRAC value or the calculated BAC value exceeds a predetermined value in one or, if appropriate, in several consecutive measurements.

14. Method according to one of claims 1 to 13, characterized in that a matching algorithm or a classification method from the field of machine learning is used to determine the body data and / or the facial data, in particular a neural network trained with reference images.

15. Method according to one of claims 1 to 14, characterized in that a predetermined heuristic is used to determine the body data and / or the facial data, for example the distance between the detected upper lip and lower lip of the person to determine the opening state of the mouth.

16. A computer-readable storage medium comprising instructions that cause a data processing unit (3) to execute a method according to one of claims 1 to 15.

17. Device for determining the alcohol content of a person in a vehicle (1), comprising an image recording unit (2), a data processing unit (3), an air alcohol measuring device (4) and a database (5), characterized in that the device is set up to carry out a method according to one of claims 1 to 15.

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