Device and method for protecting an operational area, computer program

Abstract

The invention relates to a device for protecting an operational area, comprising N sensors measuring N pieces of information (INF2, INF4, INF6) regarding the presence of a human being in the area, a circuit for converting the information into Boolean signals, a calculator for calculating an instantaneous mass for each of the 2N N-tuples, 2N conditional probabilities, a conditional probability, the maximum (M) of these probabilities, comparing the maximum (M) to a threshold (S), and, if the maximum (M) is greater than or equal to the threshold, sending an indication (IND1) of a human violation alert to the information display interface (8), and, if the maximum (M) is less than the threshold, sending an indication (IND2) of no zone violation alert to the interface (8). Figure 5

Description

Title of the invention: Device and method for protecting an operating area, computer program

[0001] The invention relates to a device for protecting an operating or caution zone, a method for protecting the operating or caution zone and a computer program for implementing this method.

[0002] The field of the invention relates to industrial radiography using gamma rays or X-rays, called radiological shots, for the non-destructive testing of welds on metal parts in nuclear power plants for producing electricity.

[0003] The non-destructive testing method using gamma or X-ray emission is used on concrete and a wide variety of welds of metal parts such as those of gas pipelines, water pipes, tanks and structural elements. In particular, this technique is commonly used to check the strength of welds on thick metal parts whose integrity is essential for the safety of the installation and / or its availability. The operators carrying out these industrial radiography operations are called radiologists and they operate in the field in teams of at least 2 people.

[0004] The principle of industrial radiography consists of exposing an object to be radiographed by an X-ray or gamma ray source and placing a detector behind this object. The latter will reveal the different densities of the radiographed object and identify potential defects. In industrial radiography, the density of metal parts is such that it is necessary to use sealed radioactive sources of very high activity (which may be, for example, cobalt 60, iridium 192 or selenium 75). Depending on the radioelement used and its activity, the dose rates can reach several hundred milliSv per hour at one meter from the source.

[0005] The use of such sources can potentially induce harmful health effects (burns, necrosis, death) for workers accidentally exposed. For example, for a worker exposed to a dose rate of around 600 mSv / h at 1 m from the source, in the space of only 2 minutes, he will reach the annual regulatory limit of 20 millisieverts (whole body dose) and for an exposure of one hour, cellular modifications (reversible), nausea and vomiting can occur. In fact, these industrial radiography operations can be very dangerous, particularly for workers working near the firing zones. This is why these activities are governed by very strict regulatory texts. They are often supplemented by specific requirements for each company which has use of this non-destructive testing method.

[0006] Industrial radiography therefore has the particularity of using radioactive sources with a dose rate of several hundred mSv / h, which can lead to very serious health consequences if workers are accidentally exposed to them.

[0007] To overcome this, a so-called operation zone delimits a physical area that is prohibited from crossing.

[0008] The various rules are dedicated to protecting the workers and thus avoiding situations of overexposure of workers. This involves delimiting the physical area known as the operating zone around the device emitting X or gamma radiation, which is prohibited to unauthorized persons, the only persons authorized to enter being the radiologists carrying out the checks. This operating zone includes physical markings to visibly materialize the prohibition of access to the operating zone.

[0009] However, despite the physical marking of the operating area, deviations from the rules are noted.

[0010] Two families of events producing these deviations can be distinguished.

[0011] A first family of events corresponds to the confinement of workers not authorized to work in the operating area during the installation of the marking, the radiologists not having seen them during the installation of the marking.

[0012] A second family of events corresponds to the voluntary or involuntary crossing of the physical markings by an unauthorized person during the activity of firing gamma rays or X-rays.

[0013] An objective of the invention is to obtain a device for protecting an operating or caution zone, a method for protecting the operating or caution zone and a computer program for implementing this method, which make it possible to reinforce the protection of the operating or caution zone, which are reliable and which make it possible to warn radiologists in real time of the presence or penetration of people into the operating or caution zone during radiological shooting activities.

[0014] To this end, a first object of the invention is a device for protecting an operating or caution zone, characterized in that the device comprises N sensors for measuring N information on the presence of a human being in the operating or caution zone, where N is a natural number greater than or equal to 2, and an information presentation interface, characterized in that the protection device comprises, in association with the N sensors, N circuits configured to convert the N information from the N sensors into N Boolean signals Bi t for i being a first integer ranging from 1 to N and for each instant you, each boolean signal Bife can take either a human presence value in the area of ​​operation or caution, or a value of absence of human beings in the area of ​​operation or caution, the protection device comprises a calculator configured to take into account 2 N N-tuples / n of the Boolean signals corresponding to the combinations of the N Boolean signals Bit each taking either the value of human presence or the value of absence of human being, the calculator being configured to calculate an instantaneous mass (j of each of the 2N N-tuples Çp yN of the Boolean signals Bit for the instant te, where where Bj, te is another of the Boolean signals 2n for j being a second integer ranging from 1 to N and i being different from j, the calculator being configured to calculate 2N first conditional probabilities ml ( S )2Y 1 for the 2N N-tuples of the Boolean signals for the instant te as a function of the instantaneous mass / » vv \ of the N-uplet / » m\\ J} V of the Boolean signals B for the instant te and as a function of the instantaneous mass ml(B- \ of the N-uplet (g 7 of the Boolean signals Bj^, having been de- finished for a moment te i previous, where m ( (%X1) " m ( +m ( -rn( (B^^ -m{ where k is a third integer ranging from 1 to 2N, the calculator (7) being configured to calculate for each of the f?|v combinations of two of the first 2N conditional probabilities a second pro OR conditional reliability k=2\ k=tl=kk*l where ( / ç \2A \ is another of the first conditional probabilities ( ( S 1I For 1 being a fourth integer ranging from 1 to 2N and k being different from 1, the calculator being configured to calculate the maximum of the second pro conditional abilities m U=2Ar; l=2N;k*l\, Sl< the calculator being configured to compare the maximum to a prescribed threshold and to, in the case where the maximum is greater than or equal to the prescribed threshold, send to the information presentation interface a first indication of an alert of violation of the operating zone or of caution by a human being, in the case where the maximum is less than the prescribed threshold, send to the information presentation interface a second indication of no alert of violation of the operating zone or of caution by a human being.

[0015] Thanks to the invention, a system is obtained which makes it possible to warn in a greater number of cases that an intruder is in the operating area or has entered the operating area in a greater number of cases. The invention thus increases prevention.

[0016] According to an embodiment of the invention, the N sensors comprise at least one weight detection mat by pressure on a surface of the mat, providing as information a value of weight present on the surface, the mat being associated with a first circuit configured to compare the weight value provided by the weight detection mat with a pre-recorded value of weight of presence of human being on the surface, and to provide as first Boolean signal Bi,te either the value of presence of human being in the operation or caution zone in the case where the weight value provided by the weight detection mat is greater than a prescribed and pre-recorded value of weight on the surface, or the value of absence of human being in the operation or caution zone in the case where the weight value provided by the weight detection mat is less than or equal to the prescribed and pre-recorded value of weight on the surface.

[0017] According to one embodiment of the invention, the N sensors comprise at least one stereovision sensor providing as information an image of the operation or caution zone, the stereovision sensor being associated with a second circuit configured to recognize a human being in the image and to provide as a second Boolean signal either the value of presence of a human being in the operation or caution zone in the case where the second circuit recognizes a human form in the image, or the value of absence of a human being in the operation or caution zone in the case where the second circuit does not recognize a human form in the image.

[0018] According to one embodiment of the invention, the N sensors comprise at least one distance measurement sensor, providing as information, at least one distance measured by reflectometry of a beam emitted from a determined fixed emission point located in the operation or caution zone in at least one determined direction towards at least one other determined fixed point, which is distant from the determined fixed emission point and is configured to reflect the beam towards the sensor of

[0019]

[0020] distance measurement, the distance measuring sensor being associated with a third circuit configured to compare the distance provided by the distance measuring sensor with a pre-recorded threshold of distance of absence of human being between the other determined fixed point and the distance measuring sensor and to provide as third Boolean signal B^e either the value of presence of human being in the operation or caution zone in the case where the distance provided by the distance measuring sensor is less than the pre-recorded threshold of distance of absence of human being, or the value of absence of human being in the case where the distance provided by the distance measuring sensor is greater than or equal to the pre-recorded threshold of distance of absence of human being. According to one embodiment of the invention, the N sensors comprise at least one distance measuring sensor, providing as information, several distances measured by reflectometry of several beams emitted from a determined fixed emission point located in the operation or caution zone in several distinct determined directions towards several other determined fixed points, which are distant from the determined fixed emission point, are distinct from each other and are configured to reflect the beam towards the distance measuring sensor, the distance measuring sensor being associated with a third circuit configured to generate a perimeter surrounding the measured distances, to compare the generated perimeter to a pre-recorded perimeter of absence of human beings and to provide as a third Boolean signal B3fe either the value of presence of human beings in the operating or caution zone in the case where the generated perimeter is modified with respect to the pre-recorded perimeter of absence of human beings, or the value of absence of human beings in the case where the generated perimeter is identical to the pre-recorded perimeter of absence of human beings. According to one embodiment of the invention, N=3, the calculator is configured to take into account the 8 triplets (fi. y1 = (BB^t B^jj of the first, second and third Boolean signals B^ and Bjj corresponding to the 8 combinations of the first, second and third Boolean signals B^ B -, and B^ which each take either the value of presence of human being, or the value of absence of human being, the calculator is configured to calculate the instantaneous mass Boolean signals B^ and for the moment te, where / d tj D \ cal- D^te ) - ---------------------g------------ ÇSk )8 j For the 8 triplets B~>^ of the First, Second and third Boolean signals B-^ B2tc and B^c for the instant te as a function of the mass instantaneous m{B\Je, B2.te- B3 ^ ) of the triplet function of the instantaneous mass m^By B2t , B3t । I am for the moment you and in j Boolean signals By.\, By.i, of the triplet , B^ having been determined for the previous moment, where m ( Su J = m ( 0,0,0 ) + m ( B^ B^r B^ )-((1(0,0,0)- / (1(5^, m(Su) = m( 0,1,0) + m(Bu^ B^, •> m(S3ti) = m{Q,Q, 1)+m(Byel, By? •> m(S^e) = m(0,l, 1) + m(B^p •> m(S5je) = m(l,l, l)+m(BÜE!, By^, m(S6jJ = m(l,0, 0) + m(Bu^ B^, m ( 5¾ ) ~ m ( 1,1, 0 ) + m ( BUi,, B^, B-^ ) -m(0,l, 0)-m(B^ B^, B3^ ) B^4 ) -m(0,0, 1) -rr^B^ B^ B3^ ) B^)-m(Q,tl)-m(Bu^ B^ B3^ ) B3tA ) -m(UB^ B^ ) B3M )-m( 1,0,0) -mfB^, 5^p B^ ) By-x ) ~m(l,l, 0) •m(Bu |, B^^, B^t.[ ) m(S^ = m(1,0,1)+™^, B.^, B^)-m(l,0,1)- / «(B^, B^,, B3^ ) the calculator is configured to calculate for each of the 28 combinations of two of the first 8 conditional probabilities )8 j the second probability conditional / r _ ml k~& / -8; k^l \ , Qu Ü. A-=8; (=8; k^l\ / 8 \ / / \ 8 \ / / \ 8 \ / / \ 8 \ Skt, S}f] =m S*; ) )+m((Su) )-m[(Sk() 4=1; 1=};M / V -eJk=U \V Ue / k=UV \V u'Jk=\) where j8 j is the other of the first conditional probabilities j8 j for 1 being the fourth integer from 1 to 8 and k being different from 1, the calculator is configured to calculate the maximum (M) of the 28 second conditional probabilities / rni . । .¾ t ' i 11 I

[0021] According to an embodiment of the invention, the instantaneous mass / / DX of the N-uplet / d Vv of the Boolean signals Bjj ] for the previous instant Ui equal to an initial instant t0 is initialized to a determined value, recorded in a memory of the computer.

[0022] According to one embodiment of the invention, the determined value is equal to zero.

[0023] A second object of the invention is a method of protecting an operating or caution area, in which N information on the presence of a human being in the operation or caution zone is measured by N measuring sensors, where N is a natural integer greater than or equal to 2, characterized in that the method further comprises the following steps: conversion, by N circuits associated with the N sensors, of the N information from the N sensors into N Boolean signals BiJe for i being a first integer ranging from 1 to N and for each instant te, each Boolean signal Bife can take either a value of presence of human being in the operation or caution zone, or a value of absence of human being in the operation or caution zone, a calculator being configured to take into account in the calculation 2N N-tuples t )N of the Boolean signals Bite corresponding to the combinations of the N Boolean signals B^ each taking either the value of presence of human being, or the value of absence of human being, calculation, by the calculator, of an instantaneous mass j of each of the 2N Tuples of the Boolean signals Bitc for the instant te, where :-—----

[0024] where B, h is another of the Boolean signals Bile for j being a second integer ranging from 1 to N and i being different from j, calculation, by the calculator, of 2N first conditional probabilities m ( ( S ) 2 1 for the 2N N-tuples . Vv of the Boolean signals for the instant te as a function of the instantaneous mass ( p . yN j of the N-tuple yv of the Boolean signals for the instant te and as a function of the instantaneous mass yV j of the N-tuple of Boolean signals Bjje (having been determined for a previous instant Ui, where m (U-JL1) = m ( (¾) m) where k is a third integer ranging from 1 to 2N, calculation, by the calculator, for each of the (J2N combinations of two of the 2N first conditional probabilities of a second probability conditional / rm\ k=2N-, 7=2*';^ , WHERE *=1; / m SjJ =m( (Sk! ) )+^7((5½) )-ml(S / f) ) z / Jl=iM ^'k^dv ^^d \v *^4=1 / \v '^d^d where ( / ç \ d \ is another of the first conditional probabilities n\ of) k=1) ( ( S )2À I For 1 being a fourth integer ranging from 1 to 2N and k being different from 1, ZU k^-'k=J calculation, by the calculator, of the maximum of the Ç2N second conditional probabilities k=2\ l=2N-,k*lk=tl=ï k*l comparison, by the calculator, of the maximum to a prescribed threshold and for in the event that the maximum is greater than or equal to the prescribed threshold, send to the information presentation interface a first alert indication of violation of the operating zone or caution by a human being, in the event that the maximum is lower than the prescribed threshold, send to the information presentation interface a second indication of absence of violation alert of the

[0025]

[0026]

[0027]

[0028] area of ​​operation or caution by a human being. A third subject of the invention is a computer program for implementing the method of protecting an operating or caution zone as described above, comprising code instructions for implementing the calculation and comparison steps, when executed by a computer. The invention will be better understood upon reading the description which follows, given solely by way of non-limiting example with reference to the figures below of the attached drawings. [Fig.l] represents a schematic perspective view of an installation on which the device for protecting an operating or caution zone can be installed, a method for protecting the operating or caution zone and a computer program for implementing this method, according to the invention. [Fig.2] represents a schematic perspective view of an installation on which the device for protecting an operating or caution zone can be installed, a method for protecting the operating or caution zone and a computer program for implementing this method, according to the invention.

[0029] [Fig.3] represents a schematic view from above of an installation on which the device for protecting an operating or caution zone can be installed, a method for protecting the operating or caution zone and a computer program for implementing this method, according to the invention.

[0030] [Fig.4] represents a schematic view of a device for protecting an operating or caution zone according to an embodiment of the invention.

[0031] [Fig.5] represents a flowchart of a method for protecting an operating or caution zone according to an embodiment of the invention.

[0032] Figures 1 to 3 show an installation on which the device 100 for protecting an operating or caution zone Z is installed. This installation may be, for example, a nuclear power plant for producing electricity. In this operating or caution zone Z there is an industrial radiography device 1000 as mentioned above, comprising a source 1001, or apparatus 1001, emitting X-rays or gamma rays (or radioactive source 1001), for example a gammagraphy device or other, in which this source is stored, to carry out a radiographic shot. The industrial radiography device 1000 comprises a detector 1001b of the X-rays emitted by the source 1001 or of the gamma rays emitted by the source 1001. The detector 1001b is placed at a distance from the source 1001 and behind an object O to be radiographed by the X-rays emitted by the source 1001 or by the gamma rays emitted by the source 1001.The detector 1001b may be of the film or digital type or other. The object may be metallic such as for example a metal part, a metal weld, such as those of gas pipelines, water pipes, tanks and structural elements or other.

[0033] The operating zone Z is delimited by physical marking 1002 informing people of the danger linked to the industrial radiography device 1000 in operation. The operating zone Z delimits a prohibited crossing zone. This physical marking 1002 may comprise vertical walls 1003 or walls 1003, one (or more) signage support(s) 1004. The signage support(s) 1004 may comprise the following signaling elements: signs 1005 or signage posters 1005, one (or more) light beacon 1006, such as for example a light triangle 1006, one (or more) barrier tape 1007 delimiting the operating zone Z (a person presence detector, which triggers a flashing light of the signaling element (light-emitting diode(s) or other) may be provided). A luminous triangle 1006 can be placed at the right of the marking 1002.The barrier(s) and / or more generally the physical marking 1002 is / are located at a distance from the source 1001 for which the dose rate is 25 pSv / h. The operating zone Z can be delimited in a two-dimensional or three-dimensional space. The source 1002 must be indicated by a dedicated beacon 1008, called . sentinel, whose function is to spatially identify where the industrial radiography device is located in the operating zone Z and which may be a flashing beacon 1008, the beacon 1008 being placed near the source 1002. An audible warning device may be provided (emitting an audible radiological shooting call, or a pre-recorded audible message) to warn workers working near the operating zone Z that radiographic shooting activities are about to begin. The workers who carry out industrial radiography operations are called radiologists. They work in teams of at least 2 people. In the following, workers other than radiologists who are either confined in the operating zone or who cross it will be called "intruders".

[0034] The caution zone is beyond the operating zone Z and surrounds the operating zone, as shown by way of example in [Fig.3].

[0035] In the following, the invention is described for a method, a device and a computer program for the protection of the operating zone Z. Of course, the invention could also be applied to a method, a device and a computer program for the protection of the caution zone (the terms "operation zone" to be replaced in this case by the terms "caution zone").

[0036] In [Fig. 4], the device 100 for protecting the operating zone Z according to the invention comprises N sensors 2, 4, 6, which measure during the first step E1 N information INF2, INF4, INF6 on the presence of a human being in the operating zone Z, and an information presentation interface 8. N is a natural number greater than or equal to 2. The N sensors 2, 4, 6 are arranged in the operating zone Z or in view of the operating zone Z. [Fig. 5] represents a flowchart of the method for protecting the operating zone Z according to the invention, implemented using the protection device 100. The information presentation interface 8 can be located in the operating zone Z or outside the operating zone Z.

[0037] In the following, for any Boolean B, the symbol B denotes the complement of B, as is known to those skilled in the art for Booleans.

[0038] The protection device 100 comprises N circuits 72, 74, 76 which convert during the second step E2 respectively the N information INF2, INF4, INF6 of the N sensors 2, 4, 6 into N Boolean signals Bi)e (or binary signals). The first natural integer i ranges from 1 to N for each present measurement instant te, where the sensor has carried out the measurement. Each Boolean signal B^ can take either a value 1 of presence of a human being in the operating zone Z, or a value 0 of absence of a human being in the operating zone Z. The N circuits 72, 74, 76 are associated respectively with the N sensors 2, 4, 6. The N circuits 72, 74, 76 can be integrated respectively with the N sensors 2, 4, 6 or be connected respectively with the N sensors 2, 4, 6.

[0039] The protection device 100 comprises a calculator 7, which takes into account in the calculations of the 2N N-tuples (yN) of the Boolean Bite signals corresponding to the 2N combinations of the N Boolean Bite signals each taking either the value 1 of presence of human being, or the value 0 of absence of human being for the first natural integer i ranging from 1 to N.

[0040]

[0041]

[0042] For the first natural integer i ranging from 1 to N and for the second natural integer j ranging from 1 to N and i being different from j, the calculator 7 calculates during the third step E3 an instantaneous mass j N j of each of the 2N N-tuples of the Boolean signals BiJe for the present instant k, where n \ “2N The Boolean signal Bj te is therefore another of the Boolean signals Bite, In the equations, B, t denotes the Boolean (or binary) complement of B In the equations, Bj tc denotes the Boolean (or binary) complement of Bj^, During the fourth step E4, for the third natural integer k ranging from 1 to 2N, the calculator 7 calculates 2N first conditional probabilities / / ç \ 2A \ for the 2N N-tuples / p. p Boolean signals Bj^ for the moment te as a function of the instantaneous mass j of the N-tuple Çg of the Boolean signals Bjte for the instant f, and as a function of the instantaneous mass j of the N-uplet (B - ) V of the Boolean signals Bj^ ] having been determined for an instant Li

[0043]

[0044] previous, where The instant Li is an instant, which is before the instant k of measurement. The first pro- conditional powers m \ are the conditional probabilities between the events at the previous instant te_i and at the present instant te. During the fifth step E5, for the third natural integer k ranging from 1 to 2N and for the fourth natural integer 1 ranging from 1 to 2N with k different from 1, the calculator 7 calculates for each of the combinations of two of the first 2N probabilities conditional 2a \ a second conditional probability

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] SO, 1 Z=2'\ M \ / , , \ / vx 2n \ / / \ \ / / 1, =m \ +m XL H XLJ - m ; e> k=ti=kM / \ ^=1 / \ ^=1 / V k=i / \ / ç 12 ' j is another of the first conditional probabilities As a reminder, The second conditional probability m । k=2!' ; l=2' :k*i\ is the pro- * II conditional ability of the two singletons / / ex 2^\ and / / o \ \. m kje J ] J m J i ) During the sixth step E6, the calculator 7 calculates the maximum M of the second conditional probabilities । k=2\ l-2!v: kri \, that is to say S>T ! I k=l; l=hM / / / rik=2'1=2 , M M = Max m ] Skt, S1t During the seventh step E7, the computer 7 compares the maximum M to a prescribed threshold S. In the case where in the seventh step E7 the computer 7 has determined that the maximum M is greater than or equal to the prescribed threshold S, the computer 7 sends to the information presentation interface 8 a first indication IND1 alerting a violation of the operating zone Z by a human being. The device 100 and the method according to the invention have thus determined that a human being is in the operating zone Z or has entered the operating zone Z. An alert is thus sent to the information presentation interface 8, for the person(s) located in the operating zone Z or outside the operating zone Z. Step E7 can be implemented by a decision module of the computer 7. The decision module then develops an alert from the maximum values ​​of the conditional probabilities on the detection events.

[0051]

[0052] In the case where in the seventh step E7 the computer 7 has determined that the maximum M is lower than the prescribed threshold S, the computer 7 sends to the information presentation interface 8 a second indication IND2 of absence of alert of violation of the operating zone Z by a human being. The device 100 and the method according to the invention have thus determined that no human being is in the operating zone Z or has entered the operating zone Z. The invention thus allows an alert system and restitution of data from the calculator 7 intended for radiologists, co-activity workers or any other worker involved in site monitoring (Risk Prevention Supervision Station (PSPR)). The invention makes it possible to improve co-activity in the installations of electricity production during maintenance phases.

[0053] The information presentation interface 8 is one (or more) perception and alert peripherals compatible with the constraints of the environment, and may comprise, for example: - One (or more) visual perception devices: rotating beacon(s) or light-emitting diode(s) or indicator light(s) and / or screen(s) (computer, tablet, mobile phone, portable terminal), or other, - One (or more) auditory perception devices: loudspeaker and / or audible alarm device, - One (or more) haptic and / or tactile perception devices: vibrating bracelet(s) worn by people and / or bone conduction interface, or other.

[0054] The information presentation interface 8 may be provided on a monitoring station or center or on any portable terminal, carried by people.

[0055] In the case where the information presentation interface 8 is provided on a supervision station or center or on any portable terminal, carried by people, this makes it possible to make the device 100 and the method according to the invention communicate and to interact with the radiologists or with the intruders to alert them of the unauthorized penetration of the intruder into the operating zone Z.

[0056] The first indication IND1 of alert of violation of the zone Z of operation by a human being is an alert of crossing the marking or an alert of intruders being locked in the zone Z of operation. The first indication IND1 of alert of violation of the zone Z of operation by a human being can be sent to the radiologists via a wireless transmission on their bracelet for example. This information can also be transmitted to the supervision station or to any other person or system connected with the radio firing operations. In addition, a restitution of the data IND1 from the computer 7 by a tablet type means or any other appropriate means indicating information linked to the intruder and / or to the proper functioning of the device is also communicated to the radiologists and to all other persons and systems previously mentioned.Messages concerning the intruder could also be transmitted to the intruder himself if the latter is equipped with a means of communication capable of interacting with the computer 7.

[0057] Above, radiologists may not be distinguished from intruders or may be distinguished from intruders.

[0058] Furthermore, radiologists are required in their work to regularly enter and leave the operating zone Z. According to a variant, the fact that radiologists ignore the alert associated with their movement in the operating zone Z allows them to focus their vigilance solely on intruders. This variant consists of identifying radiologists to distinguish them from intruders so that IND1 alert messages are not sent for radiologists located in or outside the operating zone Z. For this, one of the radiologist recognition systems that would be retained is to generate a Bluetooth message by a transmitter worn by each radiologist. This message would be received and processed by the computer 7. In this case, the IND1 alert messages concerning them would be ignored. Furthermore, it would be possible to locate radiologists using triangulation using Bluetooth Mesh technology (registered trademark) by adding gyroscopes.

[0059] The calculations mentioned above, carried out by the calculator 7, make it possible to calculate the Bayesian probabilities mentioned above. The Decision module activates the emission of an alert (IND1) or not (IND2) depending on the values ​​of the conditional / Bayesian probabilities of the detection events at times Ci and te.

[0060] According to one embodiment, as in the examples indicated below, in order to optimize the energy autonomy of the entire method and the device 100, a pre-processing of the data at the sensors is implemented. Indeed, if this is not the case, a data flow is continuously generated by the sensors and the computer 7 which is costly in energy whether there is detection or not by the sensors. This pre-processing can consist of recording only the information INF2, INF4, INF6 of the sensor which corresponds to a detection (change of state compared to the previous instant) and / or retaining to record only the Boolean signals Bije which correspond to a detection (change of state at the present instant te compared to the previous instant te l).

[0061] According to the embodiment shown in Figure 4, the N sensors comprise a mat 6 for detecting weight by pressure on a surface 60 of the mat 6, providing as information INF6 a value of weight present on the surface 60. The mat 6 for detecting weight by pressure and the surface 60 of the mat 6 are arranged in the operating zone Z, for example horizontally or otherwise. The mat 6 is associated with a first circuit 76.The first circuit 76 compares during step E2 the weight value provided by the weight detection mat 6 to a pre-recorded weight value of the presence of a human being on the surface 60, and provides as first Boolean signal By (also referenced T) either the value 1 of the presence of a human being in the operating zone Z in the case where the weight value provided by the weight detection mat 6 is greater than a prescribed and pre-recorded weight value on the surface 60, or the value 0 of the absence of a human being in the operating zone Z in the case where the weight value provided by the weight detection mat 6 is less than or equal to the prescribed and pre-recorded weight value on the surface 60. The first circuit 76 can for example be integrated into the mat 6. Of course, several weight detection mats 6. weight / pressure could be provided in the operating zone Z. The prescribed and pre-recorded weight value is for example greater than or equal to 5 kg and less than or equal to 70 kg, in particular less than or equal to 20 kg. For example, the prescribed and pre-recorded weight value is equal to approximately 10 kg. The first Boolean signal provided from the mat 6 is sensitive to the passage or presence on its surface 60 of a person.

[0062] According to the embodiment shown in Figure 4, the N sensors comprise a stereovision sensor or stereovision camera 4, providing as information INF4 an image of the operating zone Z, containing distance information provided by the stereovision. An infrared stereovision sensor and a color monovision sensor (in red, green, blue) may be provided. The stereovision camera or sensor 4 is arranged in the operating zone Z or aims at the operating zone Z. The stereovision sensor or stereovision camera 4 is associated with a second circuit 74.The second circuit 74 recognizes a human form in the image and provides as a second Boolean signal (also referenced C) either the value 1 of presence of a human being in the operating zone Z in the case where the second circuit 74 recognizes a human form in the image, or the value 0 of absence of a human being in the operating zone Z in the case where the second circuit 74 does not recognize a human form in the image. Of course, several cameras 4 or stereovision sensors could be provided in the operating zone Z or in view of the operating zone Z, for example two stereovision cameras 4. The second circuit 74 can use a three-dimensional depth map obtained by the stereovision camera or sensor 4 and a one-dimensional image obtained by the monovision sensor.

[0063] According to the embodiment shown in [Fig. 4], the N sensors comprise one (or more) distance measuring sensor(s) 2, providing as information INF2, a distance measured by reflectometry of a beam emitted from a determined fixed emission point 21 of this sensor 2, located in the operating zone Z. The determined fixed emission point 21 emits the beam in one (or more) determined direction(s) towards another determined fixed point (prescribed target or other), which is distant from the determined fixed emission point 21 and is configured to reflect the beam towards a receiver 22 of the distance measuring sensor 2. The distance is measured by reflectometry of the beam, which was emitted by the sensor 2 then reflected towards the sensor 2, i.e. by analyzing the time of flight of the beam emitted by the sensor 2 then reflected towards the sensor 2.

[0064] The beam(s) may be light and / or laser. The distance measuring sensor 2 may be of the LIDAR type (acronym for light or laser distance detection and estimation). The other fixed point determined may be in the zone Z of operation.

[0065] The distance measuring sensor 2 is associated with a third circuit 72.

[0066] According to a first possibility of this example, the third circuit 72 compares the distance provided by the distance measuring sensor 2 to a pre-recorded threshold of distance of absence of human being between the other determined fixed point and the distance measuring sensor 2. The third circuit 72 provides as third Boolean signal (also referenced L) either the value 1 of presence of human being in the zone Z of operation in the case where the distance provided by the distance measuring sensor 2 is less than the pre-recorded threshold of distance of absence of human being, or the value 0 of absence of human being in the case where the distance provided by the distance measuring sensor 2 is greater than or equal to the pre-recorded threshold of distance of absence of human being. The pre-recorded threshold of distance of absence of human being is equal to the distance between the fixed point 21 determined of emission and the other determined fixed point. Of course, several distance measuring sensors 2 could be provided.

[0067] According to a second possibility of this example, the N sensors comprise one (or more) distance measuring sensor(s) 2, providing as information INF2, several distances measured by reflectometry of several beams emitted from a determined fixed emission point 21 located in the operating zone Z. The determined fixed emission point 21 emits the beams in several distinct determined directions towards several other determined fixed points, which are distant from the determined fixed emission point 21, are distinct from each other and are configured to reflect the beam towards a receiver 22 of the distance measuring sensor 2. The distances are measured by reflectometry of the beams, which have been emitted by the sensor 2 and then reflected towards the sensor 2, that is to say by the analysis of the time of flight of the beam emitted by the sensor 2 and then reflected towards the sensor 2.The measured distances provide indications of the shape and geometry of the premises in which the operating zone Z is located.

[0068] The distance measuring sensor 2 is associated with a third circuit 72.

[0069] The third circuit 72 generates a calculation of the perimeter surrounding the measured distances (distance field), then compares the generated perimeter to a pre-recorded perimeter of absence of human beings. The third circuit 72 provides as a third Boolean signal either the value 1 of presence of human beings in the operating zone Z in the case where the generated perimeter is modified with respect to the pre-recorded perimeter of absence of human beings, or the value 0 of absence of human beings in the case where the generated perimeter is identical to the pre-recorded perimeter of absence of human beings.

[0070] The information provided by sensors 2 and 6 and signals obtained from sensors 2 and 6 make it possible in certain cases to detect a person in zone Z. operation, which could not be recognized by sensor 4 alone because of hidden parts in the images of sensor 4.

[0071] The computer 7 may be or comprise one (or more) computer(s), one (or more) processor(s), one (or more) microprocessor(s), one (or more) control circuit(s) or others. The computer 7 may have been programmed by a computer program, comprising code instructions for implementing the method, when it is implemented on this computer 7.

[0072] According to an embodiment shown in Figure 4, the circuits 72, 74, 76 performing the conversions during the second step E2 can be implemented by a calculation interface 72, 74, 76 (for example a calculation card, which may have one or more microprocessors, or other), which is respectively associated with each sensor 2, 4, 6 or connected to each sensor 2, 4, 6 or which is part of each sensor 2, 4, 6. The calculation interface 72, 74, 76 makes it possible to recover the electrical signals from the sensors 2, 4, 6 and to transform them into high-level digital information (Boolean signals ^¾.) by specific programming.

[0073] The computer 7 can be distributed over several physical parts. Thus, according to an embodiment shown in Figure 4, the part 70 of the computer 7 performing the steps E3, E4, E5, E6 and E7 is distinct and distant from the parts 72, 74, 76 performing the conversions of the second step E2. The part 70 of the computer 7 can be in the form of a central unit or computer platform (in English: hub). For example, the parts 72, 74, 76 carrying out the conversions of the second step E2 are each connected to their respective transmitter 72a, 74a, 76a with antenna, which sends by a wireless communication link data comprising the respective Boolean signal Bl!e to a receiver 70b with antenna connected to the part 70 of the computer 7. The wireless communication link can be according to the IEEE 802.15 standard, for example of the Bluetooth type or other.Alternatively, the parts 72, 74, 76 performing the conversions of the second step E2 are connected to the part 70 of the computer 7 by wires sending data comprising the respective Boolean signal. The data comprising the respective Boolean signal Bit may also comprise for each sensor the measurement time te (for example a timestamp) and / or the N information INF2, INF4, INF6 of the N sensors / or the nature of the sensor and / or the identification of the sensor and / or the status (energy level of the sensor) and / or the quality of the wireless communication link when it is provided. This data may be provided in a vector. Contextual labeling of the data may be done by the computer 7.

[0074] The sensors 2 and 4 can be integrated into the various modules constituting the beaconing 1002. These can be the sentinel beacon 1008, the triangles 1006 for preventing radio shots, the posts supporting the barrier tape 1007 or any other material used for the beaconing 1002. It can also be considered according to the beaconing plan to use dedicated support equipment for sensors 2 and 4. Sensor(s) 6 can be used in particular in passages at the level of crinoline ladders or door entrances.

[0075] In nuclear power plants for the production of electricity, the radiologists, after having recovered all the equipment necessary for their gamma firing operation, head towards their worksite. Before installing the beaconing comprising the device 100, the radiologists must pair the different sensors 2, 4, 6 with the part 70 of the computer 7. To do this, they can carry out a simple action using a dedicated remote control or using a module of their data restitution means (tablet, etc.) by activating a button / application. Then, they deploy the beaconing 1002 by referring to the previously established beaconing plan. The latter integrates the positioning of sensors 2, 4, 6. If an intruder is locked in the operating zone Z inside the 1002 marking or is about to cross it, then an alert can be sent to the radiologists via a connected bracelet system and / or a tablet and / or the PSPR and / or an audio system.

[0076] According to an embodiment shown in Figure 4, the instantaneous mass ( / n yv \ of the N-tuple / d . yv of the Boolean signals Bp for the moment Ci 171 ( \ Z>. / A : / j=[J 3 ' j=l equal to the initial time t0 (for example t0 = 0) is initialized to a determined value, recorded in the memory 71 of the computer 7.

[0077] For example, this determined value is zero. Thus, at startup, that is to say at the instant te i = t0 = 0, the instantaneous mass is initialized to 0, because the system has not yet detected any presence of the intruder.

[0078] The case of the embodiment example mentioned above and shown in Figures 4 and 5, in which N=3, is described in more detail.

[0079] The calculator 7 takes into account in the calculations the 8 triplets ( p ) 3 = ( B^tJ) of the first, second and third Boolean signals By^ B^ and B%jc corresponding to the 8 combinations of these first, second and third Boolean signals B ^2.t, and 7?^., which each take either the value 1 of presence of human being, or the value 0 of absence of human being.

[0080] Q = TxCxL is the discernment framework (the set of events / hypotheses that can be taken by the set of sensors 2, 4, 6 in the example above). Each triplet of Q is coherently timestamped each time an event of T, C and L occurs at a time te. Let 2Q be the set of parts A of Q. We have Card(Q) = 8 and Card (2Q) = 28=256.

[0081] The instantaneous mass çq j is a mass function on Q, which is defined by m : 2Q [0, 1] such that m(4>) = 0 and £ m(A) = L where ¢) denotes the set empty.

[0082] The instantaneous mass g. j or m(A) is interpreted as the confidence carried strictly in the subset A.

[0083] The computer 7 calculates during the third step E3 the instantaneous mass m( (By)3 J = m(B^ B2„ B3t ) of each of the 8 triplets B^, 5¾. of the Boolean signals B^, and B^ for the instant te, where / n DD \ 51. / ,:52, / ,.+51. / ,52 / ,+5:1 / .:53,2,.+51, / ,:53, / ,+52,4:53, / ,.+52 / / 53,+ m{Bye, B^ B3jc ) — g

[0084] . During the fourth step E4, for the third natural integer k ranging from 1 to 8, calculator 7 calculates the first 8 conditional probabilities ( ( $ \8 1 AVA=i / for the 8 triplets (Bif, B2je, B^) of the first, second and third Boolean signals By^ B2je and B3( for the instant te as a function of the instantaneous mass m(B^ B2;. B3j ) of the triplet Bu„ B^ B2t for the instant te and as a function of the instantaneous mass m( . To of the triplet By 4, B2ry, B2. / of the signals Booleans By B^-i, B^y. for the moment Li, having been determined, where m(Sy) - m(Q,Q,0) +m(By^ By^ ByA) -w(0,0,0) • m(Byei, B^, ByA] m(S2.te) = m(0,l,0)+m(By;i, B^, m(S3y = m(0,0,1)+m(Bu,, B^, •> m(Sye) = m( 0,1,1) +m(Bye], B^, m(S5y = m(l,l, 1) +m(Byei, B^, •> m(s6y = m( 1,0, 0) +m(By^, By^ •> m ( S21e ) = m ( 1,1, 0 ) + m ( B p P m(sy = m(l,0,1) +m(Byei, By^ B3^ )-^(0,1,0)-^(51^, B2^, ) 3^1 ) -«<0,0, 1) -miBy^ B^ ByA ) <u-i )-m(0,l, 1)-m^by^ byec bya ) )-m( 1,1,1)-miBy^ By^, By} ) <u-1 )-m( 1,0,0)-m(by^ b2^, byea ) 5^1 )-m(U,0)-mtBy^ B2^ ByeA ) B^a )-m( 1,0, 1)-mtBy^ B2^ ByA )

[0085] It follows from the above calculations that:

[0086] m(o,o, 0) = | ,

[0087] m(0,L0)=| ,

[0088] m(0,0,l)=| ,

[0089] / 77(0,1,1)=1 ,

[0090] / / 7(1,1,1)=1 ,

[0091] / 77(1,0,0)=1

[0092] / 77(1,1,0)=1 ,

[0093] / 77(1,0,1)=1 . conditional

[0094] During the fifth step E5, for the third natural integer k ranging from 1 to 2N and for the fourth natural integer 1 ranging from 1 to 2N with k different from 1, the calculator 7 calculates for each of the 28 combinations of two of the first 8 probabilities \ 8 X the second conditional probability iW, where 1; M / (1 V k=& 1=8, M \ / . . « \ . s \ / . . s \ / , . s \ ]5\.f, S,. | )+ / n((S / f) I

[0095] So, j8 ) is the other of the first conditional probabilities

[0096] During the sixth step E6, the calculator 7 calculates the maximum M of the 28 second conditional probabilities Â=8; 1=8; tel k=}; l=l,M

[0097] According to an embodiment shown in Figure 4, the instantaneous mass, B^, B3f?4) of the triplet BB^i, 5¾., of the Boolean signals B2it.], B^f for the instant te_i equal to the initial instant t0 (for example t0 = 0) is initialized to a determined value, recorded in the memory 71 of the computer 7.

[0098] For example, this determined value is zero. Thus, at startup, that is to say at the instant te4 = t0 = 0, the instantaneous mass of the 8 triplets Bit,. B2Je is initialized to 0, because the system has not yet detected any presence of the intruder. The device 100 and the method according to the invention are adaptable and easy to deploy by radiologists themselves and not by specialists. The device 100 and the method according to the invention can be dismantled quickly and easily at the end of the gamma shooting worksite. The device 100 and the method according to the invention can be integrated into the usual equipment for signaling the operating area.The device 100 and the method according to the invention can communicate with radiologists via simple and perceptible means in dark and noisy environments.

[0099] The device 100 and the method according to the invention may be capable of detecting both the approach of an operator near the marking and their crossing. For this, two zones can be distinguished in [Fig.3]: - the “caution” zone corresponding to an approach, for example, of approximately 2 m from a worker as close as possible to the markings without crossing them (for which there is an increased risk of potentially crossing the markings), - the operating zone Z for which the worker would cross the markings.

[0100] Radiologists may be warned by the device 8 in a differentiated manner depending on the zone Z or the caution zone in which an unauthorized person is located.

[0101] If the system must detect the "caution" zone, it must not detect further outside this zone. Indeed, in the case of co-activities, workers can operate beyond the caution zone without increasing the risk of crossing the markings. However, infrared sensors (current state of the art) are not capable of filtering detections according to distance. If this type of sensor were used, radiologists would receive all alerts without distinction of those which are relevant in the context of monitoring their site. From an ergonomic point of view, the feedback of information in quantity without filtering the alerts to the radiologists would be counterproductive and would at the very least be a hindrance to the use of the device.Home security alarm systems are not suitable for the purposes of the invention because they all use infrared motion detectors that sense heat emanating from a person or associated object at a given distance. However, these infrared sensors cannot filter the detection information based on distance. Indeed, in the case of intrusion into homes, the alarm is triggered when there is a significant change / variation in the infrared radiation field and in this case the notion of distance is not important. In industrial environments covered by the invention, indicated above, this type of system is not suitable because of the many possible heat sources.

[0102] The device 100 and the method according to the invention can have an energy autonomy of at least 24 hours.

[0103] In a variant, the sensor 2 can be used to determine the position of the intruder. In terms of visualization on the alert means 8 and restitution of the data available to the radiologists, the latter will have the possibility of visualizing a signal (of the dynamic point type) indicating the position of the intruder as it moves. For this, a manual version or an automated version are possible. For the manual version, the radiologists will have to pair each sensor 2, 4, 6 with a point located on the digital plan of the site available on the means 8 alert and data restitution. For the automated version, the pairing will be done automatically using a three-dimensional plan / image of the room where the gamma shooting operation will take place, previously recorded in the computer 7. Thus, by superimposing the previously recorded image (incorporating physical markers) and the photo of the stereovision sensor 4 taken in situ, each sensor 2, 4, 6 will then be automatically located in the digital plan.

[0104] In a variant, each sensor could be equipped with an alert device which could be of the sound and / or light and / or hologram and / or smoke and / or odor type. Its objective would be to alert the intruder once the first indication IND1 of alert of violation of the operating zone Z or of the caution zone by a human being has been sent by the computer 7.

[0105] The invention can also be implemented for all installations (nuclear power plants being dismantled, nuclear power plants under construction, conventional power plants (thermal, etc.), hydraulic dams or any other installations requiring the use of the industrial radiography process.

[0106] Furthermore, the invention can be adapted to the problems of crossing the orange zone encountered on nuclear sites (for radiation protection and corresponding to a radiological zone whose dose rate is greater than 2 mSv / h).

[0107] Furthermore, it can be used for intrusion detection purposes in a complex industrial environment.

[0108] Of course, the embodiments, features, possibilities and examples described above can be combined with each other or selected independently of each other.

Claims

Claims

1. Device for protecting an operating or caution zone (Z), characterized in that the device comprises N sensors (2, 4, 6) for measuring N information (INF2, INF4, INF6) on the presence of a human being in the operating or caution zone (Z), where N is a natural number greater than or equal to 2, and an interface (8) for presenting information, characterized in that the protection device comprises, in association with the N sensors (2, 4, 6), N circuits (72, 74, 76) configured to convert the N information (INF2, INF4, INF6) from the N sensors (2, 4, 6) into N Boolean signals Bite for i being a first integer ranging from 1 to N and for each instant te, each Boolean signal being able to take either a value (1) of presence of a human being in the operating or caution zone (Z), or a value (0) of absence of human being in the zone (Z) of operation or caution,the protection device comprises a calculator (7) configured to take into account 2N N-tuples of the Boolean signals corresponding to the combinations of the N Boolean signals Bife each taking either the value (1) of presence of a human being, or the value (0) of absence of a human being, the calculator (7) being configured to calculate an instantaneous mass m^B- )N j of each of the 2N N-tuples of the Boolean signals Bile for the instant te, where / m \ , where t is another of the Boolean signals Büe for j being a second integer ranging from 1 to N and i being different from j,the calculator (7) being configured to calculate 2N first conditional probabilities m )2* j for the 2N N-tuples p _ yv of the Boolean signals Bjje for the instant te as a function of the instantaneous mass yv j of the N-tuple of the Boolean signals for the instant te and as a function of the instantaneous mass mi (B ) V | of the N-tuple (g of the Boolean signals Bjj^, having, was determined for a previous instant te_i, where = +m(~m( (B^=l) where k is a third integer ranging from 1 to 2N, the calculator (7) being configured to calculate for each of the combinations of two of the first 2N conditional probabilities / / ç \ 2A \ a second conditional probability m\ \ykje) k=ïJ .A~2a'; ^7 fi '-h > k=k / =1; M OR where 1 (SX \ is another of the first conditional probabilities-\ k=i / tional / / ç. \ 2V \ for 1 being a fourth integer ranging from 1 to 2 m[ X ^kjJk=J N and k being different from 1, the calculator (7) being configured to calculate the maximum (M) of the (jl second conditional probabilities / r „ ) k=2N; k^i \, w %, S'

2. the calculator (7) being configured to compare the maximum (M) to a prescribed threshold (S) and to in the case where the maximum (M) is greater than or equal to the prescribed threshold (S), sending to the information presentation interface (8) a first indication (IND1) of alert of violation of the zone (Z) of operation or caution by a human being, in the case where the maximum (M) is less than the prescribed threshold (S), sending to the information presentation interface (8) a second indication (IND2) of absence of alert of violation of the zone (Z) of operation or caution by a human being. Device according to claim 1, characterized in that the N sensors comprise at least one mat (6) for detecting weight by pressure on a surface (60) of the mat (6), providing as information (INF6) a value of weight present on the surface (60), the mat (6) being associated with a first circuit (76) configured to compare the weight value provided by the weight detection mat (6) with a pre-recorded value of the weight of the presence of a human being on the surface (60), and to provide as a first Boolean signal either the value (1) of the presence of a human being in the operating zone (Z) or

3.

4. caution in the case where the weight value provided by the weight detection mat (6) is greater than a prescribed and pre-recorded weight value on the surface (60), or the value (0) of absence of human being in the operating zone (Z) or caution in the case where the weight value provided by the weight detection mat (6) is less than or equal to the prescribed and pre-recorded weight value on the surface (60).Device according to any one of the preceding claims, characterized in that the N sensors comprise at least one stereovision sensor (4) providing as information (INF4) an image of the operation or caution zone (Z), the stereovision sensor (4) being associated with a second circuit (74) configured to recognize a human being in the image and to provide as a second Boolean signal either the value (1) of presence of a human being in the operation or caution zone (Z) in the case where the second circuit (74) recognizes a human form in the image, or the value (0) of absence of a human being in the operation or caution zone (Z) in the case where the second circuit (74) does not recognize a human form in the image. Device according to any one of claims 1 to 3, characterized in that the N sensors comprise at least one distance measuring sensor (2), providing as information (INF2), at least one distance measured by reflectometry of a beam emitted from a determined fixed emission point (21) located in the operation or caution zone (Z) in at least one determined direction towards at least one other determined fixed point, which is distant from the determined fixed emission point (21) and is configured to reflect the beam towards the distance measuring sensor (2),the distance measuring sensor (2) being associated with a third circuit (72) configured to compare the distance provided by the distance measuring sensor (2) with a pre-recorded threshold of distance of absence of human being between the other determined fixed point and the distance measuring sensor (2) and to provide as a third Boolean signal either the value (1) of presence of human being in the zone (Z) of operation or caution in the case where the distance provided by the distance measuring sensor (2) is less than the pre-recorded threshold of distance of absence of human being, or the value (0) of absence of human being in the case where the distance provided by the distance measuring sensor (2) is greater than or equal to the pre-recorded threshold of distance of absence of human being, human.

5. Device according to any one of claims 1 to 3, characterized in that the N sensors comprise at least one distance measuring sensor (2), providing as information (INF2), several distances measured by reflectometry of several beams emitted from a determined fixed emission point (21) located in the zone (Z) of operation or caution in several distinct determined directions towards several other determined fixed points, which are distant from the determined fixed emission point (21), are distinct from each other and are configured to reflect the beam towards the distance measuring sensor (2), the distance measuring sensor (2) being associated with a third circuit (72) configured to generate a perimeter surrounding the measured distances,to compare the generated perimeter to a pre-recorded perimeter of absence of human beings and to provide as a third Boolean signal B^ either the value (1) of presence of human beings in the zone (Z) of operation or caution in the case where the generated perimeter is modified in relation to the pre-recorded perimeter of absence of human beings, or the value (0) of absence of human beings in the case where the generated perimeter is identical to the pre-recorded perimeter of absence of human beings.,

6. Device according to claims 2 to 4 taken together or according to claims 2, 3 and 5 taken together, characterized in that N=3, the calculator (7) is configured to take into account the 8 triplets Ÿ = (B B2t B^ ) of the first, second and third Boolean signals B^ B^, and B^ corresponding to the 8 combinations of the first, second and third Boolean signals B^ B^, and B^, which each take either the value (1) of presence of human being, or the value (0) of absence of human being, the calculator (7) is configured to calculate (E3) the instantaneous mass B^ of each of the 8 triplets (B B3l B^^ of the Boolean signals By^ and B^j for the instant te, WHERE B*e ) = ........s ' , the calculator (7) is configured to calculate (E4) the first 8 conditional probabilities ( / ç \ 8 \ for the 8 triplets (B B-> t B^j ) of the first, second and third Boolean signals Bi^, and B3I for the moment you according to the instantaneous mass m^B^, B^, ih, ) of the triplet j for the instant k and in function of the instantaneous mass ÿit , , By \ of the triplet B2 1 B2j ) Boolean signals By^, B^ ] having been determined for the previous moment, where ^(¾) = m(0,0, 0)+m(% B^., By^) - / / / (0,0, 0) B^ B^ ) miS^) = 0) + m(B^f B^ •> m(S3jf( = 7 / / (0,0, 1) + m(Bup., B^, •> = m(0,1,1) +m(BUi r B^ •> m(S5yl) = m( 1,1, 1)+ / 7)(¾.r •> = / 7 / (1,0,0)+ / / / (¾^ B2Sf •> m{Su) = 7 / 7(1,1,0) +m(Bïf^ Bt^ •> = / 7 / (1,0,1)+ / / / (¾. B^, B*^ )-m(0,L0) -m{B^f B^, B3jA ) B^ ) -m(0,0, 1) -m^B^, B^ B3t^ ) B%-1 )-^(0,1, 1) -^(¾. B^ B^ ) ) -m(l,l 1) -m^B^ B^ B^ ) B3^ )-m( 1,0,0) B2.^ B^ ) / ¾ )-m( 1,1,0) -^ / .(¾. B^ B3^ ) B^ ) -m{ 1,0, 1) -m(B^ B^ f B3^} ) the calculator (7) is configured to calculate (E5) for each of the 28 combinations of two of the first 8 conditional probabilities m( (%)L) the second conditional probability %) / =& M \ A-J; 1=1; MJ OR ï! 1 -;=& 4*' \ / ? ,8\i,\8\ / , ,8\,8\ ( 1¼ ) ■«( (+o t ,) + "'( -«t -«n (+jJ is the other of the first conditional probabilities for 1 being the fourth integer from 1 to 8 and k being different from 1,

7. A-:=8; / =8; M ) *=1; 1=1; k*l I the calculator (7) is configured to calculate (E6) the maximum (M) of the 28 second conditional probabilities / f,, „ Device according to any one of the preceding claims, ca-

8.

9. characterized in that the instantaneous mass j of the N-tuple Boolean signals (for the previous instant te i equal to an initial instant t0 is initialized to a determined value, recorded in a memory of the computer (7). Device according to claim 7, characterized in that the determined value is equal to zero. Method of protecting an operating or caution zone (Z), in which we measure (El) by N sensors (2, 4, 6) measuring N information (INF2, INF4, INF6) on the presence of a human being in the zone (Z) of operation or caution, where N is a natural integer greater than or equal to 2, characterized in that the method further comprises the following steps: conversion (E2), by N circuits (72, 74, 76) associated with the N sensors (2, 4, 6), of the N information (INF2, INF4, INF6) of the N sensors (2, 4, 6) into N Boolean signals B^e for i being a first integer ranging from 1 to N and for each instant te, each Boolean signal Bite being able to take either a value (1) of presence of a human being in the zone (Z) of operation or caution, or a value (0) of absence of a human being in the zone (Z) of operation or caution, a calculator (7) being configured to take into account in the calculation 2N N-tuples f of the Boolean signals Bite corresponding to the combinations of the N Boolean signals Bife each taking either the value (1) of presence of human being, or the value (0) of absence of human being, calculation (E3), by the calculator (7), of an instantaneous mass m^(B j of each of the 2N N-tuples of the signals Boolean Bit for now te, where ( / D H f---- where B, is another of the Boolean signals Bi t for j being a second integer ranging from 1 to N and i being different from j, calculation (E4), by the calculator (7), of 2N first conditional probabilities (B )A j of the N-tuple f yv of the Boolean signals Bj4e for the instant te and as a function of the instantaneous mass / / n Vv \ of the N- tuple t yv of Boolean signals B( having been determined for a moment before, where m ( □ +m ( (^-X) ~ m { ' K — L / \ J 1 / \ J 1 / \ J 1 / \ J * where k is a third integer ranging from 1 to 2N, calculation (E5), by the calculator (7), for each of the (J^N combinations of two of the first 2N conditional probabilities ( / ? \2N A \ I / of a second conditional probability k=2N: l=2N-k^lk=k 1=%M. OR m ( (¾. XX) = X^X) +m ( ^XJX ( 5 XJ "X \ is another of the first conditional probabilities- tional ( / $ \ 2A \ for 1 being a fourth integer ranging from 1 to 2 m \ A k'tg 'k=U k—kl—l; kïl )

10. N and k being different from 1, calculation (E6), by the calculator (7), of the maximum (M) of the Q^N second conditional probabilities / r comparison (E6), by the calculator (7), of the maximum (M) to a prescribed threshold (S) and for in the case where the maximum (M) is greater than or equal to the prescribed threshold (S), sending to the information presentation interface (8) a first indication (IND1) of alert of violation of the zone (Z) of operation or caution by a human being, in the case where the maximum (M) is less than the prescribed threshold (S), sending to the information presentation interface (8) a second indication (IND2) of absence of alert of violation of the zone (Z) of operation or caution by a human being. Computer program for implementing the method for protecting an operating or caution zone (Z) according to claim 9, comprising code instructions for implementing the calculation (E3, E4, E5) and comparison (E6) steps, when they are executed by a computer (7).

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