Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
  • G01V8/00—Prospecting or detecting by optical means
  • G01V8/10—Detecting, e.g. by using light barriers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16P—SAFETY DEVICES IN GENERAL; SAFETY DEVICES FOR PRESSES
  • F16P3/00—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body
  • F16P3/12—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine
  • F16P3/14—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine the means being photocells or other devices sensitive without mechanical contact
  • F16P3/142—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine the means being photocells or other devices sensitive without mechanical contact using image capturing devices
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V10/00—Arrangements for image or video recognition or understanding
  • G06V10/10—Image acquisition
  • G06V10/12—Details of acquisition arrangements; Constructional details thereof
  • G06V10/14—Optical characteristics of the device performing the acquisition or on the illumination arrangements
  • G06V10/145—Illumination specially adapted for pattern recognition, e.g. using gratings
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V20/00—Scenes; Scene-specific elements
  • G06V20/50—Context or environment of the image
  • G06V20/52—Surveillance or monitoring of activities, e.g. for recognising suspicious objects

Definitions

• the present invention relates to a vision sensor for security systems and its method of operation.
• security systems which monitor the area at risk in order to signal an alarm situation and/or to deactivate or control as appropriate the machine or system when a condition of intrusion of an object or a person inside the area at risk is detected.
• Some of the aforementioned security systems are equipped with a vision sensor including a telecamera, which is able to acquire, moment by moment, the image of the area at risk being monitored, and a processing unit, which has the function of processing the image acquired by the video camera so as to signal the presence/absence of objects or persons inside the area at risk to a controller; if an intrusion is signalled, said controller, in turn, "secures” or controls as necessary the system or machine that is "at risk", so as to terminate the condition of danger.
• a vision sensor including a telecamera, which is able to acquire, moment by moment, the image of the area at risk being monitored, and a processing unit, which has the function of processing the image acquired by the video camera so as to signal the presence/absence of objects or persons inside the area at risk to a controller; if an intrusion is signalled, said controller, in turn, "secures” or controls as necessary the system or machine that is "at risk", so as to terminate the condition of danger.
• the risk zone which corresponds to the area being protected is currently equipped with a predetermined graphic image which is typically referred to as a "reference pattern".
• This graphic image is created by painting or tracing out in coloured paint the geometrical shape corresponding to the reference pattern on the surface of the risk zone that needs to be monitored.
• the reference pattern corresponding to the aforementioned graphic image has the disadvantage of having particularly high production and maintenance costs, as in the long term the geometric shape is likely to deteriorate, mainly due to the accumulation of dirt on the surface of the risk zone being monitored. It is clear that such deterioration leads to a gradual reduction in the definition of the geometrical shape as it appears in the images acquired by the telecamera, resulting in the lower effectiveness and sensitivity of the security system.
• the aforesaid reference pattern also has the disadvantage of being difficult or even impossible to trace out and attach to the surface of the zone being monitored in certain working environments.
• the purpose of the present invention is therefore to provide a vision sensor for security systems that overcomes the aforementioned disadvantages.
• a vision sensor for security systems as Claimed in claim 1 and, preferably, in any one of the following Claims depending directly or indirectly on Claim 1.
• a security system as Claimed in Claim 7.
• an operation method for the vision sensor as Claimed in Claim 8 and, preferably, in any one of the subsequent Claims that depend directly or indirectly on Claim 8.
• figure 1 shows schematically a security system realized according to the specifications of the present invention
• figure 2 shows a variation of the security system shown in figure 1.
• number 1 indicates as a whole a security system suitable for monitoring a risk zone 2, to signal a condition of alarm, and/or to opportunely monitor a machine or a system 3 when the system detects a condition of intrusion of an object or a person inside said risk zone 2.
• the security system 1 essentially comprises a vision sensor 4, which in turn comprises an acquisition device 5 suitable for acquiring moment by moment the image of the risk zone 2, and a processing unit 6, which is able to receive in input the images acquired from the acquisition device 5, and is suitable for processing said images in order to signal the condition of intrusion when it detects the presence of an object or a person inside the risk zone 2.
• a vision sensor 4 which in turn comprises an acquisition device 5 suitable for acquiring moment by moment the image of the risk zone 2, and a processing unit 6, which is able to receive in input the images acquired from the acquisition device 5, and is suitable for processing said images in order to signal the condition of intrusion when it detects the presence of an object or a person inside the risk zone 2.
• the image acquisition device 5 can comprise preferably, but not necessarily, a camera, or a video or telecamera, or any other type of similar image acquisition apparatus, which can be commanded to acquire images of the risk zone 2 to appropriately encode them into an electric signal, while the processing unit 6 can be made up of a microprocessor suitable for processing the electric signal that contains the image acquired to check whether or not the latter fulfils a certain relation of similarity to a reference image; the reference image of the risk zone 2 is memorized during a learning phase, while said zone is in a condition of non intrusion, in other words without any objects or persons inside it.
• the processing unit 6 based on the comparison of the images, is able to establish the presence/absence of objects or persons inside the area or risk zone ' 2, and generates an information signal that encodes the condition of intrusion/non intrusion.
• the processing unit 6 is suitable for providing the information signal to a circuit or controller 7 of a known type which, should there be a condition of intrusion, "secures" the machine or system 3.
• the securing of the machine or system 3 by the circuit or controller 7 may for example involve the generation of an acoustic and/or visual signal indicating a state of alarm, and/or the immediate deactivation of the machine or system 3, and/or the check of certain parameters of operation (such as the reduction of the speed of the implemented process) of the machine or system 3, the variation of which leads to a decrease of the degree of danger of the machine or system.
• the vision sensor 4 comprises a projection device 8, which is able to project a predetermined image onto the surface of the risk zone 2, so as to show on said surface a reference pattern defined by a certain geometrical shape 9.
• the projection device 8 comprises a projector or any other type of similar image projection apparatus, which is able to generate a predetermined bright image, and project it onto the surface of the risk zone 2.
• the image projected by the projection device 8 onto the surface of the risk zone 2 may have any kind of geometrical shape and may be characterised by a series of wavelengths included in the spectrum of visible rays, so as to render the projected geometrical shape 9 visible to the human eye.
• the projector may also operate in the spectrum of electromagnetic radiations that are not visible, such as infrared, for example.
• the reference pattern i.e. the projected geometrical shape 9 may have a regular spatial geometric structure comprising several sub-sections that are adjacent to each other and shaped according to a certain geometrical form.
• the reference pattern i.e. the projected geometrical figure 9 has an overall geometrical configuration with the form of a chessboard, which has a number of adjacent areas, essentially of a square shape and of a predetermined size, which alternate with different colours, preferably, but not necessarily, black and white.
• the projection device 8 may be able to vary the reference pattern that it projects, so that it can be adapted to the size and shape of the risk zone 2 being monitored.
• the processing unit 6 may comprise a memory (not illustrated) containing several reference patterns with different geometrical shapes and structure, which can be projected by projection device 8 according to the geometric configuration of the risk zone 2 being protected.
• the processing unit 6 may have the option of allowing an operator to select, through a control keyboard (not illustrated) comprised in the vision sensor 4, a certain reference pattern, and it may transmit the chosen pattern to the projection device 8 which will then project it on the surface of the risk zone 2.
• the projection device 8 of the security system 1 is able to prpject a number ⁇ of reference patterns, i.e. predetermined geometrical shapes 9a, onto respective risk zones 2a that need protection, which are distinguished from each other so as to allow the vision sensor 4 to signal a condition of intrusion of an object or person in each of the risk zones 2a being monitored.
• projection device 8 When in use, projection device 8 generates the image to project the geometrical chessboard shape 9 which defines the reference pattern onto the corresponding surface of the risk zone 2 being monitored. This projection may take place continuously and independently from controls sent to other devices included in vision sensor 4, or it may be activated/deactivated depending on a control signal generated by processing unit 6.
• the acquisition device 5 acquires, moment by moment, the image projected onto the surface of risk zone 2 and sends it to the processing unit 6, which then processes it to determine whether or not there is a condition of intrusion inside risk zone 2.
• This processing may comprise a comparison between the geometrical shape in the acquired image and the geometrical shape in the reference image, or it may comprise checking any distortions or irregularities in the projected image. For example, if geometrical shape 9 corresponds to a chessboard, processing unit 6 checks the structural regularity of the areas that define said chessboard pattern; if it detects one or more irregularities in the geometric configuration of at least one area, it identifies a condition of intrusion to signal to controller 7.
• the vision sensor 4 makes it extremely simple to "generate" the reference pattern on the surface of the zone being monitored, regardless of the degree of complexity of the geometrical structure that defines said pattern.
• the vision sensor 4 is extremely versatile and adaptable to any type of environment and area being monitored, as it allows the shape and/or geometrical structure of the reference pattern being projected to be changed and redefined at any time.

Landscapes

• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Multimedia (AREA)
• Geophysics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Artificial Intelligence (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Burglar Alarm Systems (AREA)
• Alarm Systems (AREA)
• Geophysics And Detection Of Objects (AREA)

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• 2005
  • 2005-08-18 EP EP05794557A patent/EP1929333A1/de not_active Withdrawn
  • 2005-08-18 WO PCT/IT2005/000495 patent/WO2007020666A1/en active Application Filing

Non-Patent Citations (1)

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