2. Alcohol consumption limits

Common means of identifying drunkenness is by a breathalyzer or a blood test. Both methods require the person under test to come in touch with the device and to stand for an invasive test. Both procedures are time-consuming, especially the blood test, and they have a considerable cost. These techniques cannot be applied or used to monitor intoxication remotely and prevent drunk persons from being engaged in tasks that require the operator' s attention and are associated with security. For example, it is not efficient to perform a test with a breathalyzer before a football match if it is desirable to prevent the drunk persons entering the stadium. The material in this chapter presents ways for identifying intoxication by means of thermal infrared

Specific algorithms are presented in this chapter and their discrimination capabilities are explained [1–13]. The original idea lies on the fact that the blood vessels' network of the face will present increased activity when the person has consumed alcohol, changing in this way, the temperature distribution on the person's face. Accordingly, a commercial system can be derived which could be used for a fast assessment of the intoxication situation. In case of a positive inference, a breathalyzer can be employed for verifying the results. Obviously, it is not possible to obtain a thermal map of the face by means of visible light. Acquiring images from faces in thermal infrared spectrum, information related to the temperature of the face is obtained which mainly depends on the physiological condition of the person (illness, exercises, and drunkenness). The human face being in a mean temperature around 300 K, radiates according to the Wien's Law as a perfect black body, with maximum at 10 μm wavelength.

Drunkenness is a challenging physiological condition to be investigated using infrared imagery. However, most of the publications in the literature refer only to automotive anti-drunk driving systems, which utilize electrical signals from the heart or brain [14]. Extensive review of the relevant literature is given throughout the material which is being developed in this Chapter. Seven different approaches are discussed in this chapter for identifying intoxication

1. A feature vector is formed for drunk person identification by simply taking 20 different

2. The temperature differences which are presented on the face after alcohol consumption

4. Neural networks are tested on infrared images of faces for discriminating drunk persons. 5. Temperature distribution on the eyes of sober and drunk persons is studied by means of thermal infrared images. The iris and the sclera are of the same temperature for the sober

6. Isothermal regions on the face of sober and intoxicated persons are extensively studied for

7. Markov procedures are employed for the discrimination of drunk persons. This approach

3. The activity of blood vessels on the face when the person is drunk is examined.

person. For the intoxicated person, the iris becomes darker.

by means of thermal infrared images. Specifically:

points on the face of each person.

drunk person identification.

is applied only on the forehead.

are discussed.

images of the face.

146 Human-Robot Interaction - Theory and Application

Alcohol that enters our body mainly during meals, if of course not too much, do not endanger us, unless there are health reasons that prohibit its consumption. However, excessive alcohol consumption may be particularly dangerous for someone who manages machinery or drives a vehicle and may have consequences on other persons as well. The effects and symptoms that alcohol brings to the human body vary according to the amount of alcohol present in the body (milligrams). The way alcohol affects the human body begins with the absorption of ethyl alcohol into the digestive system and its final appearance in the blood and exhaled air, where authorities can measure with the well-known alcoholmeters (breathalyzers).

Each country has set its own limits on alcohol consumption, and there are countries where zero limits have been established, such as Slovakia, the Czech Republic, Romania, and Hungary. Estonia, Poland, and Sweden have placed the blood alcohol limit at 0.2 mg/mL, while Lithuania at 0.4 mg/mL. In Austria, Belgium, Bulgaria, Cyprus, Denmark, Finland, France, Germany, Italy, Luxembourg, the Netherlands, Portugal, Slovenia, and Spain, the limit is at 0.5 mg/mL. If the blood alcohol concentration exceeds 0.5 or 0.25 mg/L of exhaled air, the driver will be fined in proportion to the level of violation of the permissible limits. These limits are reduced in the case of special vehicle drivers such as ambulances, busses, trucks over 3.5 tons, motorcycles, and mopeds [15–21].

Drinks are categorized according to the amount of alcohol they contain. Blood alcohol concentration (BAC) is different for men and women depending on their weight, the amount of drinks they consume and at different time instances after consumption. The effects on each individual according to the indication of the BAC are as follows:

• 0.2–0.3 mg/mL: The person has a slight euphoria and shyness, a laxity, a loss of coordination and perhaps a little dizziness.

of thermal infrared. At the same time, our body absorbs thermal radiation from the environment. The skin emits as nearly perfect black body (emissivity = 0.98) and based on the Wien's law, the wavelength for the maximum of its emission is at 9.5 μm. Therefore, thermal imaging devices such as thermal infrared cameras designed for human body inspection operate in the

Intoxication Identification Using Thermal Imaging http://dx.doi.org/10.5772/intechopen.72128 149

The use of infrared radiation has become popular as infrared thermography [22] in medicine, since the 1960s to record the temperature of human skin. Infrared thermography is the technique that measures the heat (infrared radiation) emitted by the body and displays the temperature distribution on the surface of the body. Measurements are made with special cameras that detect infrared without coming into contact with the body. The intensity of the thermal radiation is transformed into an electrical signal and this in a color thermogram, in which the hottest spots are presented in stronger colors. An infrared image is an optical map of surface skin temperature that can provide accurate temperature measurement but cannot quantify blood flow on the skin. In order to explain the thermographic images, it is necessary to have a good understanding of the physiological mechanism of blood flow on the skin and the factors that affect the heat transfer to it. From our understanding regarding blood flow on the skin, heat transfer between tissues and skin temperature has changed rapidly over the past 40 years, allowing us to better represent and understand thermal measurements. At the same time, the improvement in camera sensitivity coupled with improved CCD technology and the development of computational imaging sys-

Modern technology provides accurate temperature measurement with accuracy better than 0.05C without getting in or touching the skin. These systems produce high-resolution images at high speed and the measurements are quantitative. When measuring the temperature of the skin under the influence of a cold environment, its temperature distribution is heterogeneous. On the contrary, the temperature distribution of the skin is more homogeneous in warm conditions. During exposure to heat or intensive exercise, the blood flow in the skin may be increased in order to increase the consumption potential. When the human being is exposed to a cold environment, the surface of the skin restricts the flow of blood and thus becomes a perfect insulator. In

Another procedure for controlling blood flow to the skin is dynamic thermography which includes local cooling or heating of the skin [23]. The ability of blood to transfer heat between the various levels of tissues to the skin can be predicted by models. These models are based not only on conductivity, tissue density, specific heat, and temperature of the tissues, but also their metabolic needs as well as the speed flow of the blood. A disadvantage of infrared thermography is that it cannot directly demonstrate that the increase in temperature is due to the increase in blood flow. One way to prove this is to combine infrared thermography with other direct

The Thermo Vision Micron A10 Model infrared camera was used to capture the thermal images from the face. This camera has an operating wavelength range from 7.5 to 13 μm, and

these hypothermic conditions, our skin works to maintain the core body temperature.

tems have improved the noninvasive thermography method.

blood flow control techniques such as Laser Doppler.

4. Experimental procedure and the database

range of 7–14 μm.


Driving with a blood alcohol concentration of 0.8–2.9 mg/mL is a criminal offense and if the person is legally drunk. Also, if the alcohol concentration in the blood is above 3.0 mg/mL, death occurs from alcohol poisoning.

The relationship between alcohol concentration in the blood and alcohol in the exhaled air should be highlighted. The amount of alcohol contained in 1 mL of blood is the same as the amount of alcohol contained in 2100 mL alveolar air. This corresponds to 0.24 mg/L of alveolar air. According to the above, for an average adult weighing 300–400 mL of pure alcohol, death occurs.

Alcohol contained in a drink is almost absorbed by the gastric tube. The absorption rate of alcohol depends mainly on:


Alcohol is distributed more rapidly to the tissues that have the greatest perfusion, but over time, it is redistributed everywhere. The greater the amount of water contained in a tissue, the more it is influenced by alcohol, for example, blood and nervous tissue. Conversely, it occurs in fat and bone tissues.
