RU2571921C2 - Method of filtering binaural effects in audio streams - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: method comprises calculating the difference between frequencies of left side and right side channels of an audio stereo signal; presenting the digitised audio signal in the form of a certain set of amplitude readings derived through defined time intervals and representing a certain number of binary bits, and via Fourier transform, presenting the audio signal in the form of coefficients which correspond to amplitude and phase values of fundamental harmonics, after which malicious frequency effects in the audio file are identified. This enables to protect users of mass-communication equipment from open malicious effect of multimedia (audio) content in real time.

EFFECT: enabling detection of malicious binaural effects in audio streams.

4 dwg, 1 tbl

Description

The invention relates to means for protecting individual, group and mass consciousness of citizens from hidden harmful influences in audio streams.

The most common options for hidden malicious influences in audio streams circulating on the Internet, taking into account the restrictions imposed by modern characteristics of the technical channels of information transfer and physiological features of the auditory analyzer, are binaural beats in the field of bioeffective frequencies. Consider the content of this type of impact.

Binaural stimulation is listening to artificially generated monotonous sound signals in stereo headphones with the aim of creating “pure” binaural rhythms of a given frequency in the listener's brain. The term "binaural rhythm" ("binaural beating") (from Latin bird - "two" and auris - "ear") is the sound effect that occurs when listening to stereo sounds of close frequency through different channels (right and left). At the same time, a person feels the beating of a pulsating tone with a frequency equal to the difference in frequencies perceived by the left and right ear. For example, when one ear hears a pure tone with a frequency of 300 Hz, and the other 308 Hz (the frequency difference should not exceed 25 Hz), the hemispheres of the human brain begin to work synchronously, and as a result, the listener feels a special sound beat with a "difference" frequency equal to 8 Hz (308-300 = 8 Hz). When sound signals of two different frequencies are present in the right and left ears, the brain calculates the phase difference between these signals (the brain superimposes the data of the two signals), which results in a third - “difference” - frequency, audible and perceived as a binaural rhythm.

The binaural rhythm frequency is the difference between the frequencies of the left and right channels of the stereo audio signal. By artificially superimposing binaural beats on top of each other, it is possible to form the rhythmic activity of the brain in the so-called bioeffective frequency range and thus cause a person to have the desired picture of electromagnetic wave vibrations in the brain, and with it the desired state of consciousness, which is characteristic of this picture. The characteristics of the main bioeffective frequencies are presented in table 1, known from the article by O. Khabarov Bioeffective frequencies and their relationship with the natural frequencies of living organisms // Biomedical Technologies and Radioelectronics, 2002, No. 5, pp. 56-66.

Table 1 Title frequency Hz Amplitude, μV Description Delta rhythm 0.3-4 50-500 The rhythm of a sleeping person Theta rhythm 4-8 10-30 The rhythm of a completely relaxed state and transition to a state of sleep, anesthesia Alpha rhythm 9-13 30-60 The rhythm of a waking person; connected with the ability to abstract thinking Beta 1 rhythm 13-25 3-10 Wake rhythm Beta 2 rhythm 25-35 (dominates the frontal parts of the brain) Gamma rhythm 35-100 5-15 Sporadic wakefulness

In the natural environment surrounding a person, such a phenomenon as “pure” binaural beats is absent. Therefore, under certain conditions, binaural stimulation can cause serious harm.

The world practice approach to protecting the psyche of users from potentially hazardous materials includes mainly legislative measures, as well as software and hardware methods.

The legislative methods for protecting the rights of minors on the Internet are most fully implemented in the United States, the country that is the world leader in the number of legislative acts in this area. Among the existing laws, it is worth mentioning the 1998 Act on the Protection of the Private Life of Minors, which enshrines the mandatory classification of web resources for children under 13 years of age in order to provide more effective control by parents of the work of children on the Internet. Another bill, the Act on the Protection of the Private Life of Minors, establishes a rule according to which the dissemination of private information about children under the age of 16 is possible only after the appropriate consent of their parents. Minors cannot have their Internet address, personal channel, etc. The Federal Communications Commission. This Act requires within 1 year to develop special rules to regulate the activities of minors in the Internet sphere. The Children's Internet Protection Act restricts access to a number of online resources containing obscene information in public places, such as schools and public libraries. Commercial filtering software packages are used for filtering, however, in some states, for example, in Pennsylvania, blocking of IP addresses at the provider level is used. Also in the United States and Canada, a rule has been introduced for the production and sale of devices that allow adults to block for children access to Internet resources containing obscene content, as well as scenes of violence, debauchery, cruelty, and murder.

In Germany, in accordance with the provisions of the State Agreement on Media Services concluded by the government with representatives of the media, a special body has been established - the Commission for the Protection of Minors in the Media, which monitors information in television and radio broadcasting and the Internet throughout the country, also distribution of DVD, CD, VHS, etc. The list of prohibited materials, according to the Law on the distribution of materials harmful to youth, includes propaganda of violence, Nazi ideology, Holocaust denial, child porn afiyu, sexual discrimination against women, sadism, sexual rape and others. In addition, Germany has a "voluntary monitoring of multimedia service providers association", performing self-regulatory body of the function. Most search engines, including Google, Lycos Europe, MSN Deutschland, AOL Deutschland, Yahoo !, T-Online and T-info, have joined the Voluntary Self-Control for Multimedia Service Providers agreement, which filters list-based websites. , compiled and published by the German Federal Department of Media Resources Harmful to Youth.

In the UK and Australia, the same tasks are carried out mainly through government programs. In the United Kingdom, Internet regulation is based on a program called the Internet Child Protection Plan for the Internet, which brings together government, the Internet industry and human rights organizations. To coordinate the activities of all participants created "Center for the protection of children from online exploitation." One of the main activities of the Center is the fight against pedophilia on the Internet, for which a team has been created to study online pedophilia. In addition to the above, in order to combat the spread of pornographic information on the Internet, a public organization called the Internet Observation Fund has been created, in which Internet service providers actively contribute to its financing.

Canada has adopted a national strategy to protect children from sexual exploitation on the Internet, designed to combine the efforts of representatives of the Internet industry and law enforcement agencies, as well as aimed at developing forms of self-regulation.

In the Russian Federation, amendments to the Federal Law of the Russian Federation “On Communications” and the Federal Law of the Russian Federation “On Information, Information Technologies and Information Protection” may become the primary legislative protection measures:

- introduction of the definition of the Internet and the Internet operator (provider) in the Federal Law "On Communications";

- Supplementing the Federal Law “On Communications” with a norm obligating telecom operators providing access to the Internet (providers), to install, at the user's request, software filters and other means that suppress access to information prohibited from dissemination by the legislation of the Russian Federation;

- Supplement of the Federal Law “On Information, Informatization and Information Protection” with a norm obliging state bodies and local self-government bodies in accordance with their powers to carry out functions to protect children from illegal information distributed on the Internet.

The main public protection measures in the Russian Federation include:

- Creation of hot lines to combat illegal Internet content, their integration into international systems for monitoring illegal content (IN-HOPE, etc.);

- educational activities aimed at increasing the level of awareness of the problem of aggressive Internet content in government bodies, the Internet community (round table conferences, etc.);

- educational activities aimed at improving the culture of using the Internet - guidance for parents, teachers and children on using the Internet in schools and at home;

- social advertising on television and the Internet, aimed at increasing the vigilance of adult users of Internet services with regard to monitoring the Internet activity of minors;

- creation of a network of Internet resources for young users (up to 12-16 years old), including educational and gaming resources, a search system, the possibility of safe correspondence and on-line communication between children among themselves - "Internet space for children", school social networks and advertising these resources among parents;

- financing and organization of research activities aimed at the development of monitoring systems and protection against hidden malicious effects of multimedia content on the Internet, the introduction of these products on the communications market.

One of the main drawbacks of legislative and organizational and administrative measures regarding protection against the spread of malicious multimedia content on the Internet is the high inertia of existing legal mechanisms regarding the emergence of new types of threats. So, at the end of September 2009, the Legislative Assembly of St. Petersburg approved an amendment to the law “On the standards for the distribution of printed materials, audio and video products, and other products not recommended for children” in St. Petersburg, which, among other things, prohibited to distribute “audio drugs and binaural beats” among minors. However, in November 2009, the Governor of St. Petersburg V. Matvienko returned the bill without signing, citing the fact that audio drugs are not included in the federal law “On Narcotic and Psychotropic Substances”. In turn, the head of the State Drug Control Department V. Ivanov confirmed that “sound drugs really affect the auditory receptors, and a person has a feeling of inadequate perception, but there are no legal grounds for dealing with them ...”.

At the same time, software and hardware methods and means of filtering hidden malicious content on the Internet are currently underdeveloped. The main organizations conducting research in the field of psychotechnology in Russia are the Department of Psychoecology of the Peoples' Friendship University of Russia, the Research Institute of Psychoecology of the Russian Academy of Natural Sciences, the research group of the Department of Psychiatry of the Moscow Medical Academy named after THEM. Sechenov, All-Russian Research Institute of Television and Radio Broadcasting. However, information on the availability in the Russian Federation of existing systems for technical monitoring of Internet channels in the interests of protection against the hidden transmission of malicious information in open sources is not available. Their closest analogue is the ODSV-1 device (an experimental detector of hidden inserts), developed in 2002 by VNIITR together with the National Research Center for Television and Radio commissioned by the Ministry of the Russian Federation for Press, Broadcasting and Mass Media. The device itself looks very simple: a TV, a small detector box and a computer. ODSV-1 records television programs on video tape, after which it searches for video inserts of the “25 frame” type for a duration of less than 113 ms. The decision on the harmfulness of the identified inserts is made by an expert group during subsequent review. Using the ODSV-1 device, it was found that the 25th frame was used during a mode demonstration. This shot showed the website of the company whose models were presented. One of the NTV-Plus employees confirmed the presence of hidden advertising using the 25th frame in most entertainment programs. Only one case is known when the Ministry of Press caught in the past a television company using the 25th frame. We are talking about using an invisible frame with the text: "Sit and watch only ATN." The Yekaterinburg company of the same name was deprived of a license for this for two months. The production and (or) distribution of television, video and film programs, documentaries and feature films containing hidden inserts that affect the subconscious of people is considered an administrative offense in the AK of the Russian Federation.

The obvious drawback of the described approach is the low efficiency and low productivity. Thus, there is an urgent need to develop and equip software and hardware with protection against malicious multimedia content (similar to antivirus software) for secondary and higher education institutions.

The claimed invention solves the problem of rapid and high-performance detection of malicious binaural effects in audio streams.

The essence of the claimed invention as a technical solution is expressed in the following set of essential features.

According to the invention, a method for filtering binaural influences in audio streams, including detecting binaural influences in audio files, is characterized in that the difference between the frequencies of the left and right channels of the stereo audio signal is calculated, then the digitized audio signal is presented in the form of a certain set of samples of amplitudes produced at certain intervals of time and presented a certain number of binary bits, and by means of the Fourier transform, they represent the audio signal in the form of coefficients, corresponding to the amplitudes and phases of the main harmonics, after which harmful frequency effects are detected in the audio file.

This is the totality of the essential features of the claimed technical solution, providing a technical result in all cases to which the requested amount of legal protection applies.

The technical result achieved by using the claimed invention is that due to the implementation of all the essential features of the claimed technical solution, it becomes possible to protect users of mass communication from the hidden malicious effects of multimedia (audio) content in real time.

The invention is illustrated by a drawing, in which Fig. 1 the claimed technology is illustrated by the algorithm diagram for the example of detecting binaural rhythm in a digital stereo audio signal, Fig. 2 shows the results of discrete Fourier transform for a binaural stereo signal, Fig. 3 shows the combination of channels of a compromised stereo audio fragment to obtain monophonic signal that does not have the effect of binaural beats, figure 4 shows the separation of the received monophonic s Nala again into two channels to obtain a pseudo-stereo signal not containing binaural beats.

The claimed technology is as follows.

A correctly decoded digital audio signal x (nТ) is input to the algorithm. The result of the algorithm is a decision on the presence or absence of binaural beats in the analyzed audio signal with a frequency f.

To bring the time dependence to the set of frequency harmonics and identify the frequency of the fundamental tone for each of the channels of the stereo signal, the discrete Fourier transform is used:

where T is the sampling period; n is the reference number of the sampled signal, n = 0, 1, 2, ..., N-1; k is the harmonic number of the signal, k = 0, 1, 2, ..., N-1, the harmonic frequency is k / T _ISM (T _ISM is the measurement period); W is an auxiliary function. The presence of binaural frequency differences between the channels is determined by the ratio:

The conclusion about the potential danger of the analyzed audio stream for the psychophysiological state is based on the decision rule:

Demonstrate the results of the discrete Fourier transform for a stereo signal containing a "clean" binaural rhythm masked by white noise (figure 2).

The graph clearly shows the frequency shift of the main harmonics of the right and left channels of the stereo signal by about 24 Hz, which corresponds to binaural beating in the region of the beta rhythm.

Thus, an objective sign of the presence of hidden binaural rhythms in the audio stream that affect the psychophysiological state of a person is the difference in the carrier frequencies of the right and left stereo channels, lying in the range from 0 to 25 Hz. A filter based on a discrete Fourier transform allows detecting the presence of such sections in the audio stream, listening to which can lead to a forced synchronization of the frequency of the brain with a frequency that causes a deterioration in the psychophysiological state.

Due to the peculiarities of implementation, malicious audio information is often inseparable from the audio stream of the carrier, against which it is masked. An attempt to eliminate malicious content in such cases can lead to a complete distortion of the structure and properties of the original audio stream. In such cases, the best way to neutralize the harmful effects is to completely block the compromised audio information.

At the same time, in some cases, it is possible to carry out transformations that neutralize the effects of malicious audio information while preserving the structure and basic properties of the audio stream in a mode “transparent” to the user. So, for example, if there are signs of binaural beats in the analyzed audio stream, the developed technology involves the following sequence of steps to neutralize them while maintaining the integrity and basic properties of the original audio object:

1. The channels of the compromised stereo audio fragment are combined to obtain a monaural signal that does not have the effect of binaural beats (figure 3).

2. Separation of the received monophonic signal again into two channels with obtaining a pseudo-stereo signal that does not contain binaural beats (figure 4). The figure shows the absence of displacement of the samples of the right and left channels relative to each other compared to the original signal (figa), due to the absence of binaural beats in the final audio signal.

Claims (1)

A method for filtering binaural influences in audio streams, including detecting binaural influences in audio files, characterized in that the digitized sound signal is represented as a set of amplitude samples produced at regular intervals and represented by a set of binary bits, then the sound signal is represented as coefficients by the Fourier transform, corresponding to the amplitudes and phases of the main harmonics, and calculate the difference between the frequencies of the left and right channels of the stereo audio signal, after e conclude that the dangers of analyzed audio stream for the psychophysiological state is carried out on the basis of a decision rule:

where f = | max (X _lion ) -max (X _right ) |, and max (X _lion ) and max (X _right ) are the pitch frequencies of the left and right stereo channels, determined on the basis of the discrete Fourier transform.

Images