WO2012145800A1

WO2012145800A1 - Monitoring the water safety of at least one person in a body of water

Info

Publication number: WO2012145800A1
Application number: PCT/AU2012/000446
Authority: WO
Inventors: Bruce Leigh Kiehne
Original assignee: Preservation Solutions Pty Ltd
Priority date: 2011-04-29
Filing date: 2012-04-27
Publication date: 2012-11-01

Abstract

A method of monitoring water safety of one or more persons in a body of water having a water surface is disclosed. The method includes monitoring each person within the water on an ongoing basis by repeatedly sensing for thermal IR (infrared radiation) emitted by a part of a person that is above the surface of the water within a detection zone. Conveniently producing thermal information on the IR emitted by each object within the detection zone includes producing a thermal image or thermogram showing the intensity of the IR emission of different objects in the detection zone by means of different colours. This unique thermal signature of human beings enables this technology to identify each person within the detection zone and their position within the detection zone. The method includes registering a danger signal when the person has been submerged beneath the water surface for the predetermined period of time. The method further includes an alarm that is set off in response to a danger signal being relayed. A system for carrying out the method is also disclosed.

Description

MONITORING THE WATER SAFETY OF AT LEAST ONE PERSON IN A

BODY OF WATER

FIELD OF THE INVENTION

This invention relates to a method for monitoring the water safety of at least one person in a body of water. This invention also relates to a system for monitoring the safety of one or more persons in a body of water. Yet further the invention extends to a body of water including a system for monitoring the water safety of bathers within the body of water.

This invention relates particularly but not exclusively to an apparatus for monitoring the safety of a plurality of swimmers swimming in a swimming pool. It will therefore be convenient to hereinafter describe the invention with reference to this example application. However it must also be recognized that the invention is capable of broader application. The invention extends to water safety in other bodies of water which have containment such as water features in amusement parks, tanks, dams, or reservoirs. It also needs to be borne in mind that the invention also extends to bodies of water which do not have containment such as the sea.

DEFINITIONS

In this specification the term "body of water" shall be interpreted broadly and shall include within its scope swimming pools, water features in amusement parks, tanks, dams, or reservoirs. It shall also include bodies of water that do not have containment such as the open sea.

In this specification the term "water safety" shall be interpreted broadly and shall include within its scope all issues that are related to the use of water. In particular it shall include within its scope include reducing the risk of people sinking under the surface of a body of water and the consequent risk of drowning.

In this specification the term "supervisor" shall be interpreted broadly and shall include within its scope any person having responsibility for oversight of a body of water. It might include a life guard but is not limited to such as person. It shall be interpreted to include a person without a title who is informally responsible for swimming activities within a body of water such as a swimming pool. In this specification the term "thermal IR" shall be interpreted broadly and shall include within its scope all IR (infra-red radiation) that is emitted by a body as a result of the temperature of the body.

In this specification the term "emergency situation" shall be interpreted broadly and shall include within its scope a situation where a person has been identified as having submerged beneath the water surface unintentionally and to be at risk of injury or drowning. This is to be contrasted with a situation where a person intentionally and voluntarily dives under the water surface in a situation where they are in control of their body and faculties and they can return to the water surface for fresh air when required.

In this specification the term "water installation" shall be interpreted broadly and shall include within its scope all containment structures containing water. It includes swimming pools and also features at water parks. It also includes the features around the actual body of water such as pool surround and pool fence.

BACKGROUND TO THE INVENTION

Applicant estimates that about 400,000 people die around the world each year in drowning deaths and of these approximately 9000 occur in the USA alone. Drowning is the major cause of death of children between the ages of 1 -5 years and it is also a major cause of death of people in the age group of 20-25 years. Consequently accidents in and around bodies of water that can lead to drowning is a major concern to communities around the world. Governments and regulators have recognised this problem and they have implemented strict rules for swimming pool owners and swimming pool operators.

Applicant is aware of some prior art devices that have been devised to try and reduce the incidence of drowning in swimming pools. For example Applicant is aware of a pool fence with a gated access that is used to limit access to a swimming pool to unauthorised persons when the pool is not being supervised. This can help to reduce drowning deaths because it limits access to the pool when it is not being used and it facilitate some oversight or supervision of the swimming pool when it is being used. However a clear shortcoming of this system is that it relies on a supervisor to notice when a person sinks beneath the water when the person is swimming in the pool, typically as one person within a group of people. Applicant's research has identified that a large number of drowning deaths occur when people are present in a pool area, either as swimmers or as bystanders. Quite often the person sinks without a sound and the other people with whom they are swimming do not notice them sink. One pool alarm of which the Applicant is aware contains a microphone to listen for a sound of splashing water and a processor to analyse the sound to determine if the sound indicates that an object such as a person has fallen into the pool. One clear limitation of this system is that when a person sinks in a body of water they make very little sound and this system could not be relied on to identify or register that a person has sunk beneath the surface of the water. Further such a system is only able to identify when an unauthorised swimmer falls into a swimming pool that is not being used. However it cannot monitor safety where there is a plurality of authorised swimmers swimming in a pool because they will create lots of sounds of splashing water.

Another example prior art system provides a beam of radiation, such as laser or microwave radiation, which extends across the surface of a pool. The beam of radiation is broken when a person enters the pool and this sets off an alarm. However this system suffers from the same drawbacks as those outlined above in relation to other prior art systems. A further shortcoming of this system is that it is not able to discriminate between inanimate objects such as leaves and sticks and humans and as result can set off false alarms.

Another pool safety system of which the applicant is aware uses sonar waves to detect a dangerous situation in a swimming pool. The sonar pool alarm transmits a sound wave or sonar wave through a medium which is the body of water contained in the pool by means of a transmitter submerged underneath the water. The system has a received adjacent the transmitter that senses when the sonar wave returns to the transmitter. The system determines whether there is an unusual object contained within the body of water (which might be a body) based on the time taken for the sound wave to return to the receiver. However the transmission and return of the sonar wave underneath the water is subject to the following objects or phenomena which interfere with the sonar waves:

> Pool cleaning devices that move along an internal surface of the pool;

> Air pockets caused by human activities in the pool such as swimming; and > People in the pool positioned in front of the transducer can block the sonar waves.

In addition the transducer transmits multiple sonar waves and when successive pulses of sonar waves reflect off different internal surfaces of the pool within a confined space they can cause the transducer to register false readings. In addition the pool can have a shape that defines zones that are reached by sonar waves transmitted by a sonar transducer. A shortcoming of these sonar units is that they are simply not reliable and a more robust solution is required. There are simply too many examples of situations where they will not identify a submerged person. A further disadvantage of sonar units is that they are not available at an affordable price. Consequently Governments are not able to mandate their installation by all swimming pool owners at this stage.

Clearly it would be advantageous if a new method and system for monitoring water safety within a body of water could be devised.

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a method of monitoring water safety of one or more persons in a body of water having a water surface, including: monitoring each person within the body of water by checking that at least part of their body is positioned above the water surface.

The monitoring may include identifying when any part of a person that is being sensed is no longer above the water surface (i.e. no part of the person is or remain above the water surface) and therefore is submerged beneath the surface, measuring the length of time that the person is submerged beneath the water surface, and registering a danger signal when the person has been submerged beneath the water surface for the predetermined period of time.

The monitoring may include repeatedly sensing in an ongoing manner for thermal IR (infrared radiation) emitted by a part of a person that is above the surface of the water. Repeatedly sensing the presence of a part of a person may include sensing the presence of the person at least 1 time every second. Advantageously repeatedly sensing the presence of a part of a person includes sensing the presence of the person several time a second, e.g. 10 to 2-0 times per second. In one form the method includes sensing the person about 15 -17 times per second.

The method may be applicable to a body of water being used by a plurality of persons and the method may include monitoring the water safety of the plurality of persons within the body of water. Sensing for thermal IR emitted by the person may include sensing with a thermal IR sensor arrangement that defines an IR detection zone above the water surface and producing sensing information.

Sensing may include sensing with a thermal IR sensor arrangement having at least one IR sensor that is mounted adjacent to the body of water that senses IR within the IR detection zone that effectively extends across a full surface area of the water surface. The IR detection zone may extend from a height that is close to the water surface to a height that is at least 50 cm above the surface of the water whereby to be able to sense for a part of a person projecting up above the water surface.

Sensing for the presence of a part of a person above the water surface may include producing sensing information that includes thermal information on the IR emitted by each object within the detection zone. In particular producing an image of each object in the detection zone may include producing a thermogram showing the intensity of the IR emission of different objects in the detection zone by means of different colours.

Producing thermal information on the IR emitted by each object within the detection zone may include identifying the thermal signature of a human whereby to identify the presence of each person within the detection zone and their position within the detection zone. Sensing the presence of each person within the detection zone may include producing an image of the detection zone showing each person in the detection zone and their position. Further the image of the detection zone may be presented as a visual display on a screen.

Repeatedly sensing the presence of a part of at least one person above the water may produce repeated items of sensing information indicating the persons that are in the detection zone, and the method may also include storing the repeated items of sensing information.

The method may further include comparing a plurality of items of sensing information and counting the persons present in each item of sensing information whereby to recognise when one or more persons are no longer being sensed above the water surface and therefore by implication are submerged beneath the water surface. The items of sensing information may be images or frames of the detection zone and comparing may include comparing different images or frames that are produced of the detection zone. In particular it may include comparing successive images or frames using a processing arrangement. The predetermined period of time (for which the person is submerged beneath the water) may be selected to be in the range of 30 seconds to 120 seconds and the method may include registering the danger signal when the person has been submerged for the selected predetermined period of time. In particular the predetermined period of time may be selected to be in the range of 45 seconds say for small children and inexperienced swimmers and 75 seconds for more experienced swimmers.

The method may further include relaying the danger signal to an alarm, which then issues an alarm and the alarm that is issued may be a visual and/or an audio alarm.

The method may further include recovering a submerged person from the body of water, and thereafter implementing an emergency response. The emergency response may include playing CPR instructions through audio speakers to assist with resuscitation of the person and/or alert an emergency authority to an emergency situation and the location of the emergency situation. Alerting the emergency authority may include automatically contacting an emergency authority by wireless or landline telephone and playing a pre-recorded phone call. It may also include automatically sending an SMS to the emergency authority.

The method may further include contacting other persons in the local area of the body of water to notify them of the emergency situation. For example the method may include automatically telephoning the telephone number of predetermined neighbours to alert them to the emergency situation

The method may further include selecting a number of persons that are authorised by a supervisor to use the body of water, and comparing the selected number of authorised persons with the actual number of persons counted in the water from the sensing information, and registering a person count breach when the number of persons that is sensed to be in the body of water exceeds the number of persons authorised to bathe in the body of water.

The method may include issuing a further alarm in response to a person count breach being registered in the body of water.

The method may include adjusting the number of authorised persons to accommodate additional persons who subsequently become authorised to enter the body of water and also to accommodate persons who subsequently depart the body of water. For example the method may include automatically adjusting the number of authorised persons downward when a person leaves the body of water for a predetermined period of time.

According to another aspect of the invention there is provided a method of monitoring the water safety of at least one person within a body of water having a water surface, including: sensing the presence of a part of the person that projects above the water surface; and recognising when any part of the person is no longer being sensed above the water surface whereby to indicate that the person has become submerged beneath the water surface.

The method may include repeatedly sensing the presence of a part of a person above the water surface by sensing for thermal infra-red (IR) in a detection zone above the water surface.

The method may include measuring the time that has elapsed since a part of the person has stopped being sensed above the water surface and relaying a danger signal when the time that has elapsed reaches a predetermined period of time (recognised as a dangerous length of time). The method may further include any one or more of the features of the method defined above in the preceding aspect of the invention.

According to another aspect of this invention there is provided a method of monitoring water safety of a plurality of persons in a swimming pool having water with a water surface, including: selecting an authorised number of persons who are permitted to use the body of water; monitoring the number of persons within the swimming pool in an ongoing manner, including counting the number of persons in the swimming pool; and comparing the authorised number of persons with the actual counted number of persons in the swimming pool.

The method may include registering a person count breach in response to identifying a discrepancy between the authorised number of persons and the actual counted number of persons, and issuing an alarm in response to the person count breach because the number of persons in the body of water is different to the number of authorised persons. In particular the number of persons in the body of water may exceed the number of authorised persons The monitoring of the number of persons within the swimming pool may include sensing IR emitted by a part of a person's body which projects above the water surface.

The method may include adjusting the number of authorised persons to accommodate additional persons who are subsequently authorised to enter the body of water and to accommodate persons who depart the body of water while it is being used. Optionally the method may include automatically adjusting the number of authorised persons downward when a person leaves the body of water for a predetermined period of time.

The method may include any one or more of the features of the method defined above in the preceding aspects of the invention.

According to another aspect of this invention there is provided a method of monitoring water safety in relation to a swimming pool area including a swimming pool surround and a swimming pool, including: sensing for persons within the swimming pool surround by means of a motion sensor arrangement when the swimming pool is in a non-use surveillance mode and issuing an intruder alarm when one or more persons are detected; and monitoring the condition of each person within water of the swimming pool when the swimming pool is in swimming mode and issuing a swimmer alarm when a person is submerged beneath a surface of the water for a predetermined period of time.

According to another aspect of this invention there is provided software for monitoring the water safety of one or more persons within a body of water having a water surface, the software embodied on at least one computer readable medium and operable when executed to by at least one processor to perform the method according to any one of the aspects of the invention defined above.

According to another aspect of this invention there is provided a system for monitoring the water safety of one or more persons within a body of water having a water surface, the system including:

a sensor arrangement for sensing the presence of a part of a person projecting above the water surface and relaying sensor information; and

a controller receiving the sensor information relayed by the sensor arrangement that senses when the part of the person above the water surface can no longer be sensed and that therefore the person is submerged beneath the water, and the controller relaying a danger signal when the person remains beneath the surface for a predetermined period of time.

The controller may include a clock for measuring the length of time that the person remains submerged beneath the water and when the length of time reaches the predetermined period of time the controller registers the danger signal.

The system may further include an alarm that is operatively connected to the controller and which produces an alarm in response to the danger signal from the controller, and the alarm produces an audio alarm and/or a visual alarm.

The sensor arrangement may include at least one thermal IR sensor that senses for IR emitted by persons within a detection zone above the water surface. The thermal IR sensor/s may be mounted spaced above the water surface adjacent the water surface that faces towards a detection zone extending across the water surface. In one form the IR sensor/s may be positioned at a height of 1 .0 to 2.5m above the water surface, e.g. at a height of 1 .5m to 2.0 m above the water surface.

The controller may include a controller housing, and a user interface on the controller housing. The user interface may include a visual display unit and a key pad to enable a supervisor to enter information into the controller. The controller may permit a supervisor to enter the predetermined period of time into the controller by means of the user interface. In particular the controller may permit a user to select a predetermined period of time that is in a range of 30 seconds to 120 second into the controller. The controller may permit a supervisor to enter a number of authorised swimmers by means of the user interface.

The system may include a support and the controller housing may be mounted on the support spaced above the ground and the sensor arrangement may be mounted on the support spaced above the ground. The controller may also be mounted on the support and the alarm may also be mounted on the support. Yet further the emergency response arrangement may also be mounted on the support.

The system may include an emergency response arrangement including an audio playing device that is operatively connected to the controller and a speaker that is operatively connected to the audio playing device through which audio instructions such as emergency CPR instructions can be played, in response to a direction from the controller. The system may further include a remote control that is wirelessly connected to the controller, the remote control having a user interface that enables a supervisor to operate the system from a position that is spaced away from the controller housing.

The system may include a further sensor arrangement for sensing the motion of a person or animal in a motion sensing zone that includes the body of water and a water surround zone around the body of water, and the further sensor arrangement may be operatively connected to the controller. The further sensor arrangement may include at least one sensor that is an optical detection sensor or an acoustic detection sensor. In particular the further motion sensor arrangement may include a PIR motion detector which has a sensor that detects a disturbance in the infra-red spectrum and generates an electronic signal in response thereto which is relayed to the controller.

According to another aspect of this invention there is provided a water installation including:

a containment structure having an open top containing a body of water; and a system as defined in the preceding aspect of the invention installed on the containment structure.

The system may include any one or more of the features of the system defined in the preceding aspect of the invention. The system may be suitable for carrying out the method of monitoring water safety as defined in any one or more of the preceding aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

An apparatus and method for monitoring the safety of one or more persons in relation to a body of water to reduce the risk of drowning therein, in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe several embodiments of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings:

Figure 1 is a side perspective view of a system for monitoring water safety in relation to a body of water that is a swimming pool in accordance with one embodiment of the invention; Figure 2 is a front perspective view of the system for monitoring water safety shown in Figure 1 ;

Figure 3 is a schematic circuit diagram illustrating the main components of the system for monitoring water safety shown in Figure 1 and how they are connected to each other;

Figure 4 is a schematic drawing showing the inputs and outputs for a controller for the system in Figure 1 ;

Figure 5 is an upper perspective view from one side of the system for monitoring water safety in Figure 1 installed on a body of water that is a swimming pool; and

Figure 6 is a schematic side view of the swimming pool of Fig 4 showing a person using the swimming pool having part of their body projecting above the water surface being monitored by a sensor arrangement of the system;

Figure 7 is a schematic side view of the swimming pool of Fig 4 showing a person that has become fully submerged beneath the surface of the water; and

Figure 8 is an upper perspective view a system for monitoring water safety and the swimming pool in accordance with another embodiment of the invention;

Figure 9 is a schematic diagram of the sequence of operations in the system in Figure 8;

Figure 10 is a schematic diagram of the system shown in Figure 8;

Figure 1 1 is a schematic top plan view showing the system shown in Figure 8 in operation on the pool shown in Figure 8; and

Figure 12 is an upper perspective view of a system in accordance with another embodiment of the invention installed on a swimming pool.

In Figures 1 to 3, reference numeral 10 refers generally to a system for monitoring the water safety of one or more persons suing a body of water having a water surface that is a swimming pool.

The system 10 comprises broadly an IR sensor arrangement 12 that is arranged to sense IR heat from a body within a detection zone above the water surface and a controller 14 including a processing arrangement. The controller 14 is operatively connected to the IR sensor arrangement 12 so that it can receive and process sensing information produced by the IR sensor arrangement 12. The controller 14 registers a danger signal when certain predetermined conditions are met. The apparatus 10 also includes an alarm that is indicated generally by numeral 16 that is operatively connected to the controller 14. The alarm 16 issues an audio and/or visual alarm in response to a danger signal from the controller 14.

The apparatus 10 also includes a support in the form of a support post 20 on which the sensor arrangement 12, the controller 14 and the alarm 16 are mounted. The support post 20 has an operatively upper end 22 that is spaced about 1 .5m to 2.0m above the ground and a lower end 24 mounted on or in the ground. Each of these components will be described in more detail below.

In the illustrated embodiment the IR sensor arrangement 12 comprises a single thermal IR sensor that can passively sense thermal infrared radiation in the region of the infra-red spectrum covering wavelengths extending from 3 micron to over 30 micron. Thermal infra-red radiation is emitted by the body of a human and this IR heat is passively sensed by the thermal IR sensor. The sensors are engineered to pick up the thermal signature of a human being having a body temperature of 36-38 degrees Celsius. The IR sensor arrangement 12 is mounted on the support post 20 towards the operatively upper end 22 thereof and is directed towards an area or zone in which it is required to sense thermal IR. The sensor arrangement 12 focusses IR radiation passively received from the field of view. This focused light is scanned by a phased array of infra-red detector elements which creates a very detailed pattern of temperature in the field of view called a thermogram. The thermogram is built up from several thousand points in the field of view of the array of detector elements and the time taken to make the thermogram is about 1/30th of a second. The sensor arrangement 12 then converts the thermogram into electric impulses that are sent to a signal processing unit which converts the information into a form in which it can be interpreted by a user. In particular the thermal information of the temperatures of the different regions of the field of view can appear as different colours which are selected to indicate different intensities of infra-red emission.

The controller 14 comprises a controller housing 30 that is mounted on the support post 20 about midway up the post 20 at a height that is difficult for an infant or small child to access. The controller 14 includes a user interface indicated generally by the numeral 32 mounted on a leading face of the housing 30. The user interface 32 comprises an LCD display 34 on which the information generated by the processing arrangement 16 can be displayed. The user interface 32 also includes a keypad 36 for enabling a person to enter information into the processing arrangement 16. The key pad 32 requires literacy skills to operate so that it cannot be easily operated by a preschool child.

The controller 14 further includes a processor in the form of a microprocessor 38 that is received within the controller housing 20 that is shown in Figure 3 which is a circuit diagram, but is not shown in all the drawings. The microprocessor 38 is programmed with software that enables it to process the information from the sensor arrangement 12 and register the danger signal when certain defined predetermined conditions are met. The software algorithm in the illustrated embodiment will be described in more detail below.

The controller 14 also includes some additional features which will be described briefly below. Firstly the controller 14 includes a battery pack that is housed within the housing 30 and which is charged by a transformer which steps down a supply voltage to 12 volts DC. This allows the controller 14 to operate even if there is a power blackout and it also has the result that most of the components are inexpensive and can be purchased off the shelf. The controller 14 typically also includes an arrangement that monitors power levels in the controller 14 and indicates inadequate power by means of a visual LED light 39. The light 39 is arranged on the housing 30 so that they flash when power to any of these components is insufficient or is interrupted. The controller 14 also typically includes malfunction lights (not shown) that alert a supervisor or technician to a malfunction within the controller 14. The controller 14 also has lights (not shown) that flash when the system 10 is due to be serviced. The controller 14 also has a USB port (not shown) for operatively coupling an outside computer to the processor 38 for diagnostic and maintenance purposes. The USB port may also be used to download the latest software and to install it on the processor. As the general nature of these features would be well known to persons skilled in the art and they do not form part of the invention they will not be described in detail in this specification.

The alarm 16 is an audio alarm and a visual alarm that is designed to immediately attract the attention of other people that are present in the area. In particular the alarm includes L.E.D. lights 50 on the housing 30 that illuminate when an alarm is triggered to attract attention. The alarm 16 also includes a loudspeaker 52 mounted on the housing 30 through which the various audio alarms can be sounded. The alarm 16 can also be connected to a siren that goes off when the alarm 16 is set off. The controller 14 further includes an emergency response arrangement indicated generally by numeral 56 within the housing 30 that is operatively coupled to the processor 38 for carrying out a predetermined response when an emergency condition is entered.

The emergency response arrangement 56 includes a response button 57, and a player 58 that plays a set of CPR instructions through a loudspeaker, e.g. the loudspeaker 52, which would be audible to persons in the region of the swimming pool. The emergency response arrangement 56 further includes a communication device for communicating with certain persons to notify them of the existence of an emergency. In one form the communication device is a telephone 59 that telephones one or more predetermined numbers and plays a pre-recorded message when the telephone is answered. Some functional features of the system will now be described.

The system has a "fail to surface" feature which recognises when a swimmer remains below the surface of the water for a predetermined period of time. The "fail to surface" feature is important because Applicant has identified the situation where a swimmer within a group of swimmers sinks in a swimming pool and no-one notices that the person has sunk.

The sensor arrangement 12 repeatedly senses and monitors each of the authorized swimmers in the detection zone on an ongoing basis. This sensing information is relayed to the controller 14. Sensing the person with IR depends on part of their body being above the water surface. Accordingly if a person can no longer be detected by the thermal IR sensors, they must have sunk beneath the surface and this fact is noted by the controller 14. The controller 14 measures the time that the person is below the water surface, and when this time reaches a predetermined period of time the controller 14 generates a danger signal. The controller 14 has a feature that enables a supervisor to adjust a default predetermined time setting of say 60 seconds to a predetermined time setting of 15, 30, 45 or 90 seconds. A shorter time period of say 15 or 30 seconds may be more suitable if young children are using the swimming pool. A longer time period may be more suitable for elder and more experienced swimmers. The controller 14 relays the danger signal to the alarm 16 which issues an alarm. This alerts people around the swimming pool to the risk that someone has sunk to the bottom of the pool and may need an emergency rescue. A person near the pool, e.g. a supervisor, investigates the situation and if it is not an emergency situation they simply press the reset button on the key pad. If however a swimmer is in distress and there is an emergency situation then the supervisor hits the emergency button on the controller housing which activates the emergency response arrangement.

The system has a "swimmer count" feature that enables a supervisor to enter an authorised number of swimmers into the controller 14. The system 10 then counts the number of swimmers in the pool and checks that it equals the authorised number of swimmers. The "swimmer count" feature is designed to guard against young children entering the pool without the knowledge of their care givers when it is being used by other people. Applicant has identified this situation as one that has led to a disproportionately high number of drowning deaths.

During operation of the "swimmer count" feature, an operator of the pool enters the number of people who are authorised to be in the pool at any one time via the keypad 36. Thereafter the swimmers start entering the swimming pool and as each swimmer enters the pool they are identified by the sensor arrangement and accorded a number based on their order of entry into the pool. For example the first swimmer to enter the detection zone will have the number 1 and the second swimmer to enter the detection zone will have the number 2 and so on. The software in the processor 38 compares the authorised number of swimmers against the actual number of people sensed in the pool and registers a person count breach if the actual number of people within the pool does not match the number entered by the pool supervisor. The person count breach is relayed to the alarm and a further alarm is triggered.

If a person wishes to enter the pool after the initial group of swimmers has entered the pool, then the supervisor keys a variation in swimmer numbers into the key pad and the swimmer can then enter the pool. The supervisor does a similar adjustment downward in numbers if one person leaves the pool. In a variation of the feature described above to vary the number of authorise swimmers, the system has a feature that automatically adjusts the number of authorized swimmers in the pool downward when a swimmer leaves the pool area. The system needs to adjust the number of authorized swimmers downward to factor in the departed person as otherwise it would be vulnerable to an unauthorised person entering the pool. If an authorized person leaves the pool area and does not return for five minutes, the processor 38 automatically adjusts the number of authorized persons down by one person. If the swimmer returns to the pool area after more than five minutes the supervisor needs to key in an additional authorized swimmer into the keypad 36 before they enter the pool. If they do not then a person count breach will be registered and an alarm will be triggered.

The system 10 has a "reset feature" that enables a user to reset the system by pressing a reset button on the key pad. The system 10 also resets automatically after a predetermined period of time has elapsed since a danger signal was registered.

In use the system 10 in Figures 1 to 5 is installed on a swimming pool area like that shown in Figure 5. The swimming pool area is indicated generally by numeral 60 and has a pool surround 62 that extends circumferentially around a swimming pool 64 and a pool fence 66 surrounds the pool surround 62. The pool fence 66 is rectangular and has four corners and a self-latching gate 68. The system 10 is shown mounted on the ground at one end of the pool 64 proximate to the gate 68. A detection zone 70 extends across the full surface of the pool 64 up to a height of about 1 m above the surface of the pool 64.

In use a swimmer swimming within the pool 64 typically has part of their body projecting up above a water surface 72. The IR sensor arrangement 12 senses the body heat from this part of the person above the water surface as is schematically illustrated in Figure 6. If a swimmer dives under the water surface for a short period, and then resurfaces, the person will disappear from the sensor information for a period of time. However they re-appear above the surface, before the predetermined period of time has elapsed, and therefore a danger signal is not registered.

However if the person remains beneath the water surface 72 for a predetermined period of time then the processor 38 registers a danger signal and this is relayed to the alarm 16 which is triggered. This alerts bystanders to the danger and they look for a swimmer submerged in the water. If it is false alarm they merely reset the system 10. If it is an emergency situation they press the emergency button and this triggers the emergency response arrangement 56. As described above this contacts the emergency authorities and also contacts neighbours and the like. Figures 8 to 1 1 illustrate a system in accordance with a second embodiment of the invention mounted on a swimming pool installation. As this embodiment has some features in common with the first aspect of the invention described above with reference to Figures 1 to 4 the same reference numerals will be used to indicate like components unless otherwise illustrated.

In the embodiment in Figures 8 to 1 1 the system 10 has a sensor arrangement 2, controller 14 and alarm 16 like that described above with respect to Figures 1 to 7. In addition the system 10 has a plurality of motion sensors 80 mounted on the corners of the pool fence 66 for detecting any unauthorised entry into the pool area 60 as shown in Figures 8 and 1 1 . Each motion sensor 80 is mounted on top of the corner post and faces into the pool area. Optionally each motion sensor includes a PIR motion detector which has a sensor that detects a disturbance in the infra-red spectrum and generates an electronic signal in response thereto which is relayed to the controller. The features of this system 10 are shown in the schematic illustration in Figure 10.

The system 10 in Figures 8 to 1 1 has two basic modes of operation namely a surveillance mode and a swimming mode which are shown in Figure 9. The system is in the surveillance mode when the swimming pool 64 is not in use and this is basically the default mode. The system 10 is switched to the second mode of operation which is the swimming mode when it is to be used for authorised swimming activities. In the swimming mode the system 10 monitors the safety of authorized users of the pool 64 and detects use of the pool by any unauthorized users.

In the surveillance mode the motion sensors 80 are armed to detect any entry though the pool fence 66 and into the pool surround 62. If a person entering the pool surround 62 does not disarm the motion sensors 80 within a predetermined period of time, of say 15 seconds, an intruder signal will be registered and this sets off the alarm 16. In addition in the surveillance mode, the sensor arrangement 12 repeatedly senses for IR in the detection zone 70 above the water surface 72. Accordingly if a person enters the detection zone 70 while the system 10 is in surveillance mode then a danger signal is registered and this sets off the alarm 16. When an alarm goes off, it can be turned off by a user pressing the reset button 73. The system 10 then returns to full alarm mode within about 2 minutes. However if the alarm 16 is not turned off within 60 seconds, the controller 14 takes further measures to alert other people to the intrusion into the pool area 60. The system can have L.E.D. lights 74, e.g. mounted on the support post 20 that indicate whether the system 10 is in surveillance or swimming mode. The L.E.D. lights 74 flash red when the system is in the surveillance mode and flash green when the system 10 is in the swimming mode.

In use, when the system 10 is in the surveillance mode the motion and thermal IR sensors 80 and 12 are armed and no entry at all is allowed to the pool area 60. If a person enters the pool area 60 an intruder signal is registered and relayed to the alarm 16 which sounds the alarm. If the alarm 16 is not turned off by an authorised pool operator who keys in a code then a further intruder signal is registered. The processor 58 relays the intruder signal to predetermined persons that are off-site, such as neighbours and emergency services, notifying them of a potential emergency. The system 10 then goes into full emergency mode and plays pre-recorded CPR instructions over the loudspeaker.

Before the swimming pool 64 can be used for authorised swimming activities, the system 10 is switched to the swimming mode. To do this a supervisor enters the pool surround 62 and enters a code into the keypad 32. Once in the swimming mode, the controller 14 turns off the motion sensors 80 and activates the LCD screen 30 on the controller housing 20. In the swimming mode the system 10 permits authorised persons to use the pool and only registers a danger signal if certain other conditions relating to the authorised users are fulfilled. By contrast in the surveillance mode an intruder signal is registered when a person is detected by either the IR sensors 12 or the motion sensors 80.

In the swimming mode a use of the swimming pool is initiated by an operator keying into the keypad an initial number of authorised people that will be using the pool. The system 10 registers an alarm condition when a person sinks below the water for a dangerous length of time or the counted persons in the pool does not match the authorised number of persons. Otherwise the swimming mode is the same as the operation of the system described above with reference to Figures 1 to 7.

Figure 12 illustrates a system in accordance with another embodiment of the invention mounted on a swimming pool installation that has a different shape to that in Figure 5. As this system has many features in common with the first aspect of the invention that is described above with reference to Figures 1 to 5 the same reference numerals will be used to indicate like components unless otherwise illustrated. Further the description below will focus on the differences between this embodiment and the first embodiment described above. In Figure 12 the swimming pool has an L-shape which is different to the rectangular shape of the Fig 5 embodiment. As a result the system has two supports at each end of the L-shaped pool with controllers and thermal sensors on each of the supports. The two systems are interfaced so that instructions to one system are implemented on the other. This arrangement with IR sensors at each end ensures that the full water surface of the pool is sensed and that there are no dead spots.

Applicant has recognized that water safety is more about monitoring authorised swimmers rather than identifying unauthorised users of a swimming pool. Accordingly a preferred method of providing water safety in a body of water would involve monitoring bathers who are bathing or swimming in the water so that if one of these swimmers encounters difficulties and sank to the bottom of the pool an alarm could be raised. However many prior art solutions that have been proposed in relation to water safety are designed to sense when an unauthorised person enters a pool, e.g. by jumping or diving into a pool, and then registers an alarm. However while these methods can detect unauthorized use of a swimming pool they do not and cannot monitor the safety of an authorized swimmer who is using a pool in accordance with the rules of use of the swimming pool and who sinks to the bottom of the pool. While some prior art efforts have endeavoured to detect a body of a person within a body of water, these efforts have been plagued by technical problems. It has proved to be very difficult to devise a system that can sense a bather within a body of water who has sunk to the bottom of the body of water while they are swimming.

Applicant has gone in a completely different direction and has conceived the idea of repeatedly sensing the presence of a part of a person's body above a surface of the water. By identifying and recognising when the person can no longer be sensed above the water surface, the Applicant effectively establishes when the person has sunk beneath the water surface and is at risk of drowning. Applicant has been the first person to recognize that this methodology would provide an effective way of monitoring persons for risk of drowning. It senses people within a pool in an ongoing manner and identifies when they become submerged beneath the surface of the water for a predetermined time period that poses a drowning risk.

In particular Applicant has recognised that many people have drowned in swimming pools when they have been swimming with others and no one has realized that they have got into difficulties and sunk. The person sinks below the surface of the water without making any sound. This is why one cannot rely on a person crying for help before they sink.

Thus the spark of the Applicant's invention lies in the recognition that if one wants to determine when a person sinks within a body of water one should sense the person's presence above the surface of the water on an ongoing basis, and if they disappear from above the water surface and can no longer be sensed, by implication they have sunk beneath the water.

Further Applicant has also conceived the idea of using IR that is radiated by a person's body to sense each person in the swimming pool and to monitor their presence in the pool. IR radiation is particularly suitable for this use because IR sensors are very effective at recognizing the unique thermal signature of a human being. An upper portion of the body of a bather such as the head and shoulders is very well supplied by blood and thus an IR sensor would be able to detect the IR radiation emitted by this part of the body very effectively. As far as Applicant is aware no one has previously used IR sensors for sensing the unique thermal signature of a human being in relation to pool safety. The Applicant's use of IR to sense a person above the water surface offers the sensitivity and the reliability that a method and system for achieving pool safety requires. The Applicant's technology is more robust and reliable than the prior art methods that have been proposed to date.

A key advantage of the method and system for monitoring water safety of a plurality of people in a pool described above with reference to the drawings is that it monitors the safety of people that are within the water of a swimming pool and using the pool in an authorised fashion. It senses immediately when a bather is submerged beneath the water surface, measures that time that has elapsed since the person sank beneath the water surface and when a predetermined period of time has elapsed, it sounds an alarm. The method and system works automatically and does not require the intervention if humans. It thus eliminates the human factor.

Another advantage of the method and system for monitoring water safety that is described is that the predetermined period of time can be set by a pool supervisor to different time for different bathers. For example for small children the predetermined time period could be set to 45 seconds. For more experienced swimmers it could be set at 1 minute and for even more experienced swimmers such as adult water polo players to could be set to 1 minute 30 seconds. Another advantage of the method and system described is that it senses substantially immediately when a person sinks beneath the water surface as distinct from recognising them lying at the bottom of the pool. A yet further advantage is that the sensor arrangement provides an image of the water surface and gives an indication of where the submerged person is located in the pool. This is particularly advantageous in larger pools having a large number of persons therein, e.g. at a child's birthday party.

Another advantage of the method and system described above is that it can generally identify and monitor each user in a pool and provide information to a supervisor on how the pool is being used. Further the method and system can enable a pool supervisor to enter an authorized number of swimmers into the system and to identify when this number of swimmers is exceeded and notify the supervisor. It can also identify when one or more swimmers leave the pool and adjust the observed number of swimmers in the pool. It can also enable a supervisor to add additional swimmers into the system as they are authorized to enter the pool.

Another advantage of the method and system described above is that the IR sensing technology is readily available and components can be purchased off the shelf. A further advantage is that a controller arrangement can be programmed to process the signal received from the IR sensors and send an alarm signal when an alarm condition is identified.

Another advantage of the apparatus described above is that it is able to detect a small child or infant who manages to breach a perimeter barrier of a pool area would be detected by the motion sensors and if not them by the IR sensors. In fact the apparatus will detect any use of the swimming pool whatsoever when it is not in swimming mode and generate an immediate alarm in response to this unauthorized use.

Another advantage of the apparatus described above with reference to the drawings relates to the treatment of people who are rescued with CPR treatment. It is well documented in the literature is that rescuers often panic when they are rescue a person from a swimming pool. The tendency to panic is exacerbated by the face that very often the rescuer is a mother or father of a child who is unconscious. Accordingly they have a tendency to panic when they need to apply emergency CPR treatment to that person. Sometimes they forget how to effectively carry out treatment despite having been trained in CPR procedures. An advantage of the apparatus described above with reference to the drawings is that it provides clear spoken audio instructions over a loudspeaker system on how to carry out CPR treatment in the heat of an emergency situation.

Another advantage of the apparatus described above is that once it identifies an emergency situation it automatically telephones an emergency authority and advises of the type of emergency and the street address at which the emergency is located. It also automatically telephones the telephone numbers of certain neighbouring properties and advises them of the emergency situation that has been identified. This is very beneficial because applicant has identified that in many emergency situations it is often difficult to get hold of neighbours to come and assist with the emergency situation.

It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.

Claims

CLAIMS:

1 . A method of monitoring water safety of one or more persons in a body of water having a water surface, including:

monitoring each person within the body of water by checking that at least part of their body is positioned above the water surface.

2. A method of monitoring water safety according to claim 1 , wherein the monitoring includes identifying when any part of a person that is being sensed is no longer above the water surface and therefore is submerged beneath the surface, measuring the length of time that the person is submerged beneath the water surface, and registering a danger signal when the person has been submerged beneath the water surface for the predetermined period of time.

3. A method of monitoring water safety according to claim 1 or claim 2, wherein the monitoring includes repeatedly sensing in an ongoing manner for thermal IR (infrared radiation) emitted by a part of a person that is above the surface of the water.

4. A method of monitoring water safety according to claim 3, wherein repeatedly sensing the presence of a part of a person includes sensing the presence of the person at least 1 time every second.

5. A method of monitoring water safety according to claim 4, wherein sensing for thermal IR emitted by the person includes sensing with a thermal IR sensor arrangement that defines an IR detection zone above the water surface and producing sensing information.

6. A method of monitoring water safety according to claim 5, wherein sensing includes sensing with a thermal IR sensor arrangement having at least one IR sensor that is mounted adjacent to the body of water that senses IR within the IR detection zone that effectively extends across a full surface area of the water surface.

7. A method of monitoring water safety according to claim 5 or claim 6, wherein sensing for the presence of a part of a person above the water surface includes producing sensing information that includes thermal information on the IR emitted by each object within the detection zone.

8. A method of monitoring water safety according to claim 7, wherein producing sensing information on the IR emitted by each object within the detection zone includes identifying the thermal signature of a human whereby to identify the presence of each person within the detection zone and their position within the detection zone.

9. A method of monitoring water safety according to claim 8, wherein sensing the presence of each person within the detection zone includes producing an image of the detection zone showing each person and their position within the detection zone and their position.

10. A method of monitoring water safety according to any one of claims 5 to 9, wherein repeatedly sensing the presence of a part of at least one person above the water produces repeated items of sensing information indicating the persons that are in the detection zone, and the method also includes storing the repeated items of sensing information.

1 1 . A method of monitoring water safety according to claim 10, wherein the method includes comparing a plurality of items of sensing information and counting the persons present in each item of sensing information whereby to recognise when one or more persons are no longer sensed above the water surface and therefore have become submerged beneath the water surface.

12. A method of monitoring water safety according to claim 1 1 , wherein the items of sensing information are images or frames of the detection zone and comparing includes comparing different images or frames that are produced of the detection zone.

13. A method of monitoring water safety according to any one of claims 5 to 12, wherein the predetermined period of time is selected to be in the range of 30 seconds to 120 seconds and the method includes registering the danger signal when the person has been submerged for the selected predetermined period of time.

14. A method of monitoring water safety according to any one of claims 1 to 13, further including relaying the danger signal to an alarm, which then issues an alarm.

15. A method of monitoring water safety according to any one of claims 1 to 14, wherein the method further includes recovering a submerged person from the body of water, and thereafter playing CPR instructions through audio speakers to assist with resuscitation of the person and/or alert emergency authorities to an emergency and the location of the body emergency.

16. A method of monitoring water safety according to claim 15, wherein the method further includes contacting other persons in the local area of the body of water to notify them of the emergency.

17. A method of monitoring water safety according to claim 5, wherein the method further includes selecting a number of persons that are authorised by a supervisor to use the body of water, and comparing the selected number of authorised persons with the actual number of persons counted in the water from the sensing information, and registering a person count breach when the number of persons that is sensed to be in the body of water is different to the number of persons authorised to bathe in the body of water.

18. A method of monitoring water safety according to claim 17, include issuing a further alarm in response to a person count breach being registered in the body of water.

19. A method of monitoring water safety according to claim 17 or claim 18, wherein the method includes adjusting the number of authorised persons to accommodate additional persons who subsequently become authorised to enter the body of water and to accommodate persons who subsequently depart the body of water, and wherein the method includes automatically adjusting the number of authorised persons downward when a person leaves the body of water for a predetermined period of time.

20. A method of monitoring the water safety of at least one person within a body of water having a water surface, including:

sensing the presence of a part of the person that projects above the water surface; and

recognising when any part of the person is no longer being sensed above the water surface whereby to indicate that the person has become submerged beneath the water surface.

21 . A method of monitoring the water safety of at least one person according to claim 20, including repeatedly sensing the presence of a part of a person above the water surface by sensing for thermal infra-red (IR) in a detection zone above the water surface.

22. A method of monitoring the water safety of at least one person according to claim 20 or claim 21 , including measuring the time that has elapsed since a part of the person has stopped being sensed above the water surface and relaying a danger signal when the time that has elapsed reaches a predetermined period of time.

23. A method of monitoring water safety for a plurality of persons in a swimming pool having water with a water surface, including:

selecting an authorised number of persons who are permitted to use the body of water;

monitoring the number of persons within the swimming pool in an ongoing manner, including counting the number of persons in the swimming pool; and

comparing the authorised number of persons with the actual counted number of persons in the swimming pool.

24. A method of monitoring water safety of a plurality of persons in a swimming pool according to claim 23, including issuing a person count breach in response to identifying a discrepancy between the authorised number of persons and the actual counted number of persons, and issuing an alarm in response to the person count breach because the number of persons in the body of water is different to the number of authorised persons.

25. A method of monitoring water safety of a plurality of persons in a swimming pool according to claim 24, wherein monitoring the number of persons within the swimming pool includes sensing IR emitted by a part of the person's body that projects above the water surface.

26. A method of monitoring water safety of a plurality of persons in a swimming pool according to any one of claims 23 to 25, including adjusting the number of authorised persons to accommodate additional persons who are subsequently authorised to enter the body of water and to accommodate persons who depart the body of water while it is being used.

27. Software for monitoring the water safety of one or more persons within a body of water having a water surface, the software embodied on at least one computer readable medium and operable when executed to by at least one processor to perform the method according to any one of claims 1 to 26.

28. A system for monitoring the water safety of one or more persons within a body of water having a water surface, the system including: a sensor arrangement for sensing the presence of a part of a person projecting above the water surface and relaying sensor information; and

29. A system for monitoring the water safety of one or more persons according to claim 28, wherein the controller includes a clock that measures the length of time that the person remains submerged beneath the water and when the length of time reaches the predetermined period of time the controller registers the danger signal.

30. A system for monitoring the water safety of one or more persons according to claim 28 or claim 29, further including an alarm that is operatively connected to the controller and which produces an audio and/or visual alarm in response to the danger signal from the controller.

31 . A system for monitoring the water safety of one or more persons according to any one of claims 28 to 30, wherein the sensor arrangement includes at least one thermal IR sensor that senses for IR emitted by persons within a detection zone above the water surface, and the thermal IR sensor/s are mounted spaced above the water surface adjacent the water surface facing a detection zone extending across the water surface.

32. A system for monitoring the water safety of one or more persons according to any one of claims 28 to 31 , wherein the controller includes a controller housing, and a user interface on the controller housing, the user interface includes a visual display unit and a key pad to enable a supervisor to enter information into the controller.

33. A system for monitoring the water safety of one or more persons according to any one of claims 28 to 32, including an audio playing device that is operatively connected to the controller and a speaker that is operatively connected to the audio playing device through which audio instructions such as emergency CPR instructions can be played, in response to a direction from the controller.

34. A system for monitoring the water safety of one or more persons according to any one of claims 28 to 33, including a further sensor arrangement for sensing the motion of a person or animal in a motion sensing zone that includes the body of water and a water surround zone around the body of water, and the further sensor arrangement may be operatively connected to the controller.

35. A system for monitoring the water safety of one or more persons according to claim 34, wherein the further motion sensor arrangement includes a PIR motion detector which has a sensor that detects a disturbance in the infra-red spectrum and generates an electronic signal in response thereto which is relayed to the controller.

36. A water installation including:

a containment structure having an open top containing a body of water; and a system as defined in any one of claims 28 to 35 installed on the containment structure.