MESSAGE TRANSFER TO PERSONAL DEVICES

Technical Field

The invention relates to data processing, namely, closed-circuit security television (CCTV), video surveillance, and video analytics. The invention ensures prompt alarm notifications from the objects monitored to personal devices, e.g. smart phone or touchpad. The invention can be used in safety and security, communications, transportation, retail, manufacture, sports, entertainment, housing and utility services and social infrastructure. The invention functions in local and global networks, dedicated and cloud-based servers, and can be embedded in a camera, video server, video recorder or a personal device as hardware and / or software.

Let's consider various industry solutions for the invention:

The invention can be applied in a local corporate network to promptly deliver video-data messages to staff members' personal devices via Wi-Fi wireless channel.

The invention can be applied in the global internet network to deliver alarm messages to remote users' personal devices via GSM or LTE wireless channels.

In the underground transportation security system, the invention facilitates the delivery of alarm messages to the station operator and the police officers to inform them about people and things falling on the rails. The video or picture received allows the authorised officials to promptly verify the alarm message and make a decision.

In retail and banking networks, the invention allows informing the senior cashier of prospective or actual queues. The video or picture received allows the senior cashier to decide upon whether to open another cash desk or send an assistant to an operating one. The invention can be applied by housing and utility services to inform the owners of apartments, cottages and cars of their theft or damage risk. Besides, the invention can inform parents of their children coming home from school or monitor elderly people at home.

The invention can be applied by the industry to monitor the manufacturing process and the performance. For example, the enterprise manager will receive a video message to their personal device in case of fire or smoke detection, unauthorised access to the equipment, if the team fails to start or complete an operation in due time.

The invention can be applied to guarding strategic facilities, with the authorized person receiving alarms with video data to personal devices when somebody enters a prohibited area or when you press the fire alarm. The image on the personal device allows a person to verify the alarm and take adequate measures.

The invention can be applied to sports and entertainment facilities, when visitors receive messages containing a link to a commemorative video with this visitor (e.g. going down the ski slopes or a carting drive). The invention can be applied in video surveillance systems based on the standards and/or recommendations of the Open Network Video Interface Forum (ONVIF, www.onvif.org), Physical Security Interoperability Alliance (PSIA, psiaalliance.org) or Common Alerting Protocol (CAP, http://docs.oasis- open.org/emergency/cap/ ). Prior Art

A video surveillance system generally comprises a) one or more cameras, and b) one or more video servers (DVRs), c) one or more user (operator) workstations and d) a transmission network or other video channels. Components a) are normally placed at the facility monitored, for example, in the monitored building or premises. Components b), c) and d) can be placed both at the facility monitored and elsewhere.

For the purpose of this invention, the term "video server" shall denote (include) a computer or other computing device that processes (performs video analysis, indexing, coding, transcoding), transmits and / or stores (backs up) video data.

Cameras transmit the video data obtained by video servers through the communication channels. Video servers perform analytical processing, storage and archiving of the video data received.

As a rule, analytical processing of video data by the video server is nothing but detection of motion in the field of view of the camera. A video server determines the area and intensity of motion in the frame.

In some cases, analytical processing of video data in the video server involves the use of video analytics. For the purpose of this invention, the term "video analytics" shall denote (include) computer vision methods for automated preparation of various data based on the sequence analysis of images live from the cameras or archived records. Video analytics automates the four functions of video surveillance: detection, tracking, recognition and prediction. For example, some types of video analytics perform automatic recognition of the following alarms (objects and situations): a crowd of people (queue), a person crossing the tripwire, fast movement (running) of a person or signs of fire.

Video analytics results in events, messages and / or metadata that can be delivered to users or archived for later analysis.

For the purpose of this invention, the term "event" shall refer to the data obtained from one or more event sources, when the predetermined conditions are changed. The event sources include: a video surveillance system, a source video, video analytics, sensors or users. Events transmitted to the computer system through electronic communication channels can be recorded and archived (to a system log or protocol) and / or broadcast to users as messages.

For the purpose of this invention, the term "message" shall denote the 85 information of the video surveillance system event and may include one or more of the following: time and place of the event, type of the event, attributes of the object that initiated the event, metadata and video data that describe the event.

An alarm message can inform the user of the event posing a potential threat to security, such as a fire or equipment failure.

90 Information messages can inform the user of events occurring at the facility monitored, for example, the beginning of a particular technological process or a queue in front of the cash desk.

For the purpose of this invention, the term "video archive" shall denote data stored on the video server and containing the surveillance system video codes, 95 messages, events and metadata. Metadata can include the camera ID, a timestamp, type of the situation detected; coordinates, trajectory and classification of the object, as well as detection accuracy evaluation.

A movement detector and video analytics may be embedded into the camera, thus reducing the load on the video server and the communication channels 100 between the camera and the video server. Embedded analytics allow cameras to transmit not only video, but also messages, events and metadata, that is, the results of the video analysis.

The camera or video server may be connected to external sensors (e.g., smoke or door opening) to generate events referring to the video data displayed to the user 105 and archived.

The user workstation is connected to a video server on the network and allows the user to view streaming (live) video and video archives, as well as receive alarms or information (notifications) on the situation at the facility monitored. A standard user workstation is client software for a desktop computer with a standard operating system, for example, Microsoft Windows.

Some modern video surveillance systems include user workstations for personal devices (mobile client), such as smart phones and touchpads. A standard mobile client is client software for iOS, Android or Windows Mobile.

Mobile clients allow the user to remotely view live video from the cameras and archived video recorded on a video server, using wireless communication channels, such as GSM (Global System for Mobile Communications), LTE (Long Term Evolution) or Wi-Fi (Wireless Fidelity). In addition, some mobile clients allow you to control PTZ camera (Pan, Tilt and Zoom, PTZ) or transfer video from your cell phone camera to the video archive. Unlike client software for desktop computers, mobile client present an engineering challenge due to a number of limitations imposed by personal devices: a) limited and unstable bandwidth of the wireless links used to connect personal devices to the network, b) limited battery resource, c) less powerful video playback hardware, d) personal device peculiarities, such as temporary failures of the screen or sound, and e) hardware and software compatibility issues for different personal devices and operating systems.

Some modern video surveillance systems use servers on the cloud infrastructure for fault-tolerant video storage and transfer to mobile clients. This cloud surveillance system suggests processing and storage of video data on virtualized computing resources not limited by embodiment, physical configuration or geographic location of the video server hardware.

Servers applied on cloud or dedicated computers connected to the Internet make it easier to connect mobile users to video servers, located at the facilities monitored. Thus, using a server in a global network does not require a static IP- 135 address with the Network Address Translation (NAT) to connect mobile users to the video server through the local network.

Sources of events and related messages include video analytics, a variety of sensors and measuring devices, alarm buttons, touch screens and other technical devices.

140 Event sources also include the users (operators) that generate the event based on the received image data, voice data (e.g. on the phone or a calling panel) and other signals that describe the state of the facility monitored.

CCTV functions include prompt messaging, i.e. live event message transfer to personal devices or mobile clients for immediate analysis.

145 Modern CCTV systems have the following disadvantages that hinder prompt messaging to personal devices.

First, many video surveillance systems do not support prompt messaging to personal devices in standby mode. Mobile clients of such surveillance systems can show messages (events) only on demand. In other words, the user has to open the 150 mobile client regularly and check for new messages (events). In addition, the above mobile clients require a large amount of system resources to maintain a communication session between the mobile client and the remote computer system, thus increasing the battery cell unit discharge rate.

Second, some systems use a video service of short text messages (Short 155 Message Service), SMS. This approach does not allow the user to perform operational analysis of the alarming situation by viewing the video or image of the situation. The use of video analytics to generate alarm messages always carries a high level risk of false positives, and the video data associated with the alarm help the user decide on further action.

160 Third, some of the video surveillance systems use Multimedia Messaging Service (MMS) to deliver alarm messages. The disadvantages of this approach include the high cost of each message, imposed by the mobile operator on the user (especially in the roaming mode) and limited size of the video data transmitted (typically 300 KB).

165 Fourth, some video surveillance systems use e-mail service to deliver alarm messages. The disadvantages of this approach include the lack of mechanisms to ensure timely delivery, time-consuming uploading of bulky email applications and the risk of missing an alarm lost among other e-mail messages.

Summary of the Invention

170 The invention addresses the above disadvantages and increases the efficiency and convenience of the personal surveillance device operation.

The invention results in prompt surveillance event reporting from the video server to the personal device with the possibility to view the corresponding video data.

175 Unlike its current counterparts, the invention facilitates the user's decisionmaking, reduces the time of response to messages, increases the efficiency of wireless communication channels, reduces power consumption by personal devices and communication expenses.

The invention facilitates video data delivery from the server to the personal 180 device in two stages: at the first stage the server delivers a short message with the video data link to the personal device. At the second stage, the mobile application downloads the video link from the alarm message received.

An important feature of the invention is that separate transmission of SMS and video allows the personal device to download the video from the server either 185 request or automatically, having detected a fast and / or more cost-effective Internet connection channel. For example, a Wi-Fi connection is usually free (non- chargeable), while GSM connection is fee-paying. Another important advantage is that in the event of multiple alarms, the user may select the highest priority link to download the video data based on the text 190 message.

Some versions of the invention support message delivery from the local video server to the personal device via the central server, that is, an additional Internet computer system. The central server supports routing, caching and logging messages, as well as routing and transcoding video to the available bandwidth of 195 communication channels between the central server and personal devices.

The advantage of alarm messaging through the central server is the permanent multiple connections between the central server and personal devices with no load on the LAN video server or its outbound channel (uplink). As a result, the load on the video server and the uplink does not depend on the number of mobile clients in 200 use.

The above version of the invention facilitates alarm message transmission to multiple personal devices. The message is sent from the video server to the central server only once through the limited bandwidth uplink, and is then delivered to all personal devices through the channels of the central server with larger bandwidth, 205 thus increasing the efficiency of video server resources and uplink.

Another advantage of the invention is the increased reliability of alarm delivery to the personal device. The central server generates a message queue for personal devices outside of the coverage area and passes it through wide channels when the personal device becomes available again. If the central server link is 210 faster and more reliable than the local video server uplink, the delivery of notifications to the personal device will be more reliable if transmitted via the central server rather than directly from the video server to the personal device.

A method of transmitting a prompt message, according to the invention, involves with the following stages: a) receiving at the first computer system of events and the related data that include video data and information on the video data, which include at least a link to video data;

b) generating a message based on the event and the related data, which includes at least a link to video data;

c) sending the message from the first computer system to the second computer system;

d) receiving the message on the second computer system;

e) analyzing the message received;

f) if the analysis of the message received shows the need to analyze the video data, downloading it using the link in the message.

A method of transmitting a message from the first computer system to the second computer system, taking into account the network connection fees, consists of the following steps: a. receiving at the first computer system of events and the related data that include video data and information on the video data;

b. generating a message based on the event and the related data, which includes at least a link to video data;

c. sending the message from the first computer system to the second computer system;

d. receiving the message on the second computer system;

e. determining available network connections to the Internet and their fees;

f. if there is a free network connection detected, downloading the video data from the link in the message, using one of the free network connections detected; g. if there are no free network connections detected, downloading the video data from the link in the message, using one of the chargeable connections detected, as determined by the user;

A method may be implemented in the system described below, which comprises:

245 a. the first computer system;

b. the second computer system;

c. wherein the first computer system includes:

i. one or more processors No. 1 ;

ii. data storage device No. 1 ;

250 iii. one or more programs No. 1;

iv. wherein one or more programs No. 1 are stored on the data storage device No. 1, intended to be run on one or more processors No. 1 , and including instructions for:

1. receiving the event and the related data;

255 2. generating a message based on the event and the related data, which includes at least a link to video data received; 3. sending the message to the second computer system.

d. wherein the second computer system includes:

v. one or more processors No. 2;

260 vi. data storage device No. 2;

vii. data display device;

viii. one or more programs No. 2;

ix. with one or more programs No. 2 are stored on the data storage device No. 2, intended to be run on one or more processors No. 265 2, and including instructions for:

1. receiving the message;

2. analysing the message received; 3. if the analysis of the message received shows the need to analyze the video, downloading it using the link in the 270 message.

The first computer system may include a network camera, a video server, a video recorder or a cloud server.

The second computer system may be represented by: a personal portable device, a mobile phone, a smart phone, a touchpad, a laptop, a desktop computer, a 275 touch panel or a computer built into the workplace in a building or in a vehicle.

Video can be sourced from a video sensor, camera or video encoder, as well as a network video server, video recorder, video storage server. Such video source can be a standard or special purpose computer with the disk or solid-state memory to store videos.

280 The video source can be physically located locally at the facility monitored or remotely, for example, on a dedicated or cloud server in the Internet.

The video source can be virtualized, it is not limited to embodiment, physical configuration or geographical location of the hardware.

The video source can be fixed or mobile, including embedded in a mobile 285 phone.

The video source can prepare video data dynamically on demand from the personal device. For example, having received a request from the personal device, the server uploads the video data from the storage and records to a file transmitted to the personal device.

290 Messages and / or video data may contain video analytics results, including the location, trajectory, symptoms, classification and identifiers of the objects recognized by the video analytics. Messages and / or video may contain the results of video data quality monitoring, whereas the video data is transmitted by cameras. For example, an 295 alarm message can be transmitted in the event of loss of connection to the camera, as well as in case of blackout, light exposure, focus shift or noise masking of the video data received from the camera.

Messages and / or image may comprise alarm source data including spatial coordinates of the camera, a map fragment, a map link or a text name specified by 300 the user.

Messages and / or video may contain telemetry data on the state of the sensors and actuators connected to the surveillance system, e.g. smoke, temperature, door opening.

A message can be transmitted in accordance with the specifications of the 305 ONVIF, PSIA or CAP interfaces, with a link to the video data included in one of the alarm message fields.

A message may contain several links to different portions of the video. For example, one link can lead to a single frame with the alarm object for rapid analysis of the situation, and the other link - to the full video with the alarm object 310 for the detailed analysis of the situation.

A message may contain one or more links to video data of different quality and bit rates.

A message may contain the identifier of the user (operator) initiating the message and the corresponding event.

315 A link to the video data contained in the alarm message can be specified in the format of the URI (Uniform Resource Identifier). For example, the link "http://myserver.com/video/stream.ts" leads to the protocol type "http://", the name of the server "myserver.com", the path and file name of the video data 7 video / stream.ts ". 320 A link to the video data contained in the alarm message may have the form of an arbitrary character ID, number, time stamp, the composite identifier. For example, if the event occurred after 5 minutes 10 seconds from the start of video data recording in a file, the reference

"http://myserver.com/video/stream.ts?time=5ml0s" can request video data with the

325 corresponding time delay.

The video data may contain one or more frames, as well as one or more fragments of frames.

Video data can be transmitted as streaming video supplied live from a video source or from the storage, the local video server or a central server. Standard 330 streaming video protocols are RTSP (Real Time Streaming Protocol), RTMP (Real Time Messaging Protocol), HLS (HTTP Live Streaming) and DASH (Dynamic Adaptive Streaming over HTTP). The speed and quality of the video transmitted can be automatically modified depending on the communication channel of the personal device.

335 Video data can be transmitted in compressed form, for example, using H.264,

VP8, MJPEG, JPEG, JPEG2000 encoders.

Video data can be transmitted as separate files using standard containers, for example, WebM, OGV, MKV, MP4, TS, JPG, etc.

Video data can be transmitted over wireless networks such as GSM (Global 340 System for Mobile Communications), CDMA (Code division multiple access), LTE (Long Term Evolution), Wi-Fi (Wireless Fidelity). Some versions of the invention to receive and / or send data using multiple technologies above data or transmission / reception technologies to be invented after the invention has been applied for.

345 A message with a link to video data can be transferred using push-technology, for example, based on the XMPP / Jabber, Apple Push Notification service (APNs) and Android Cloud to Device Messaging (C2DM) protocols. This delivery method is the best when the personal device is in the home cellular network and the cost of data transmission is not high for the user.

350 A message with a link to the video data can be transmitted via SMS. This approach is the best when the personal device is in the roaming mode and the cost of data transmission is high for the user. In this case, the data can be used when the data transmission service is not available in the mobile network or the personal device is turned off. Some operating systems for mobile phones, for example,

355 Android, support intercepting SMS messages and processing them in a mobile client security system.

The server can select the best delivery method for alarm with a link to video data on single or multiple criteria basis, such as availability of connection to a personal device for push-notification, user settings, tariff plan, geographic location 360 of the personal device and the time of the day / week.

A personal device can automatically download video from the video source.

A personal device can download video from the video source on demand of the user.

A personal device can store the downloaded video data in the built-in memory 365 of the personal device and / or display it on the screen.

A personal device can give a sound and / or light signal after the receipt of new alarm messages and / or downloading video data.

The server can be a separate physical (designated) or a virtual computer, i.e. alarm messages can be transmitted through virtualized computing resources, not 370 limited to embodiment, physical configuration or geographic location of the hardware. In particular, the server may comprise several computers connected into a single cloud server. The server and the video data source can be merged into a single hardware and / or software.

375 A message, according to the invention, supports not only alarm messaging, but also that of any other events, such as the availability of video data for viewing and video data recording completion.

Brief Description of Drawings

FIG. 1. One of the prompt transmission schemes with the video data 380 transferred from the local video server to the personal device via a central server.

FIG. 2. Interactions diagram of the prompt video messaging pursuant to FIG.

1.

FIG. 3. One of the prompt transmission schemes with the video data transferred from the local video server directly to the personal device.

385 FIG. 4. Interactions diagram of the prompt video messaging pursuant to FIG.

3.

FIG. 5. One of the central server schemes to send alarm messages to personal devices.

FIG. 6. One of the mobile application user interface schemes to receive 390 video alarms.

Variants of Invention Embodiment

FIG. 1 shows one of the prompt video and / or a portion of video transmission circuits from the local video server to the personal device via a central server.

395 The first computer system includes local video server 13, which can be located on the object monitored, and central server 14, which can be located on a dedicated or cloud server on the Internet. The second computer system comprises personal devices 15-16.

Cameras 1 1 , 12 transmit video data to video server 13 through the local 400 network. The local video server processes the video data with the use of video analysis algorithms and generates reports based on the results of the video analysis. In the event of the alarm, the local video server sends the corresponding message and video data to central server 14. The central server can be connected to local video servers located at various CCTV sites. The central server sends the alarm 405 message without video data to personal devices 15-16. Personal devices with access to communication channels of sufficient bandwidth download video data from the central server for display to the user. Alarm messaging server and the source video are merged into a central server 14.

FIG. 2 presents a scheme of the prompt messaging method interactions with 410 video data of FIG. 1. Local server 21 sends an alarm message with video data 24 to central video server 22. Then, central video server 22 transmits an alarm message without video data 25 to personal device 23. Next, personal device 23 sends a request with a link to the video data 26 to central video server 22. After that, central server 22 sends the requested image data 27 to personal device 23.

415 The scheme of a method described in FIG. 1-2, demonstrates the technical effect of the invention, which is transmitting an alarm message with the video data to the personal device.

FIG. 3 shows one of the prompt video and / or a portion of video transmission circuits from the local video server directly to the personal device.

420 The first computer system includes local video server 33, which can be located on the object monitored, and central server 34, which can be located on a dedicated or cloud server on the Internet.

The second computer system comprises personal device 35. Cameras 31, 32 transmit video data to on-site local video server 33 through 425 the local network. The local video server processes the video data with the use of video analysis algorithms and generates reports based on the results of the video analysis. In the event of the alarm, the local video server sends the corresponding message without video data to central server 34. The central server can be connected to local video servers located at various CCTV sites. The central server 430 sends the alarm message without video data to personal device 35. Personal devices with access to communication channels of sufficient bandwidth download video data from the central server 33 for display to the user. In this scheme the central server performs the alarm transmission function, while local server 33 is the video source.

435 FIG. 4 presents a scheme of the prompt messaging method interactions with video data of FIG. 3. Local server 41 sends an alarm message without video data 44 to central video server 42. Then, central video server 42 transmits the alarm message without video data 44 to personal device 43. Next, personal device 43 sends a request with a link to the video data 46 to local video server 41. After that,

440 local video server 41 sends the requested image data 47 to personal device 43.

The scheme of a method described in FIG. 3-4, demonstrates the technical effect of the invention, which is transmitting an alarm message with the video data to the personal device.

In comparison with the scheme in Fig. 1-2, the circuit in Fig. 3-4 generated 445 fewer loads on the central server, but more loads on the local video server and its communication channel. Fig. 1-2 scheme is preferred if one the same alarm message is delivered to several personal devices at the same time, and the users are willing to pay the cost of the additional load on the central server.

FIG. 5 shows one of the central server 510 circuits transmitting alarm 450 messages from local server 50 to personal device 59 according to one possible embodiment of the invention described in Fig. 1-2. A new alarm with the video data comes from a local server or a camera with embedded video analytics 50 to message and video reception module 51 via ONVIF protocol. Module 51 can implement the Network Video Client interface 455 (NVS) or ONVIF interface, while the local server implements the Network Video Transmitter (NVT) or Network Video Analytics (NVA) interface.

The new message and video data are placed storage in module 52 for temporary. Messages are removed automatically from storage 52 after the message delivery to all addressee personal devices or its expiry.

460 The new message arrives at the module for transmission to the personal device via the APN service 53. If the APN delivery is not possible, for example, the personal device does not have a data delivery connection, the new message is delivered via transmission module 54 and the SMS service. SMS service can be more expensive for the central server operator than APN, but cheaper for the

465 personal device user.

Personal device 59 at the time of the data connection and / or on-demand downloads the video from the link in the alarm message through module 55.

Module 55 implements an HTTP (Hypertext Transport Protocol) server for sending files (such as JPG frames or MP4 video), as well as the HLS (HTTP Live 470 Streaming) server for live video transmission to a personal device. A video data delivery protocol is selected depending on the user settings, a communication channel and the roaming mode.

Module 56 controls the all the modules, generates alarm mailing lists, connects / disconnects personal devices and controls the size of stored messages 475 and video.

Module 56 has a web-based user 58 and administrator 57 interface to set the control functions. The central server can be run on a dedicated or cloud server, for example, Amazon EC3 cloud hosting.

480 The software of the central server can be implemented in C #, Java, PHP and

Python. Messages are stored in a relational database (e.g. MySQL or PostgreSQL), or object-oriented database (e.g. db4o). Video is stored in standard or specialized file systems.

FIG. 6 shows one of the mobile application user interface circuits to receive 485 messages with the video data on the iOS operating system.

Form 60 shows the moment of receiving push-notifications for new alarm message to the central server through the APN service. If the APN service is not available, the alarm message can be sent by SMS. Sample Form 60 see in Fig. 7.

If the user opens the message with their finger, the personal device loads one 490 frame of the video data from the central server via the first link in the alarm message received. Frame transmission is carried out in the JPEG format via HTTP protocol. The frame is displayed on the video display Form 62, with the alarm object framed.

Sample Form 62 see in Fig. 9.

495 A graphical abstract of the alarm conditions, such as the framing the alarm that caused the event can be sent in XML format, as well as together with the alarm message or the video data.

The alarm frame having been pressed, the personal device requests a central server video for a stream from the second link of the alarm message. The central 500 server sends streaming video to the personal device via HLS.

Video data can be transmitted not only as the FILS stream, but also as a file, for example, MP4. From Form 62, you can jump either to Form 61 to view the list of messages or to Form 62 to handle the message.

505 Form 61 shows a list of alarms received in the form of alarm frame fragments.

Clicking on a fragment of the frame, the user jumps to Form 62.

Sample Form 61 see in Fig. 8.

Form 63 allows you to export video data, for example, by e-mail or MMS, and call the emergency rescue service (the red button with the number 1 12).

510 Sample Form 63 see in Fig. 10.

Form 64 enlarges the portion of the video data (alarm frame). Sample Form 64 see in FIG. 8.

Thus, the above user interface scheme allows you to send an alarm message to a personal device, even if the latter is in standby or roaming mode, with disabled

515 connection for data transfer. In this case the event-related video data are transferred from the alarm message link at the user's request. The separate use of the two links to the alarm frame and the video stream minimizes the amount of video data sent to the personal device and reduces the average time of the decision. Most of the decisions can be based on the analysis of a single frame without viewing the full

520 event video.

Besides, the link to a single frame image files allows generating thumbnail image of alarm messages (see Form 61).

FIG. 7 presents one possible embodiment of Form 60 shown in FIG. 6 and a new message displayed on the lock screen.

525 FIG. 8 presents one possible embodiment of Form 61 shown in FIG. 6, and shows a list of messages received and the corresponding video fragments, one fragment enlarged for easier viewing. FIG. 9 presents one possible embodiment of Form 62 shown in FIG. 6 for viewing the selected video message.

530 FIG. 10 presents one possible embodiment of Form 63 shown in Fig. 6, which allows you to handle the message received, for example export the frame or call the 1 12 emergency service.

Although the invention has been described through an example of its embodiment, this description is not limiting but is shown for reference only and for 535 better understanding of its essence, while the scope of the invention is defined by the claims below.