GB2502922A

GB2502922A - Imaging device, management device, and video monitoring system

Info

Publication number: GB2502922A
Application number: GB1316192.2A
Authority: GB
Inventors: Satoshi Maruta
Original assignee: Hitachi Kokusai Electric Inc
Current assignee: Hitachi Kokusai Electric Inc
Priority date: 2011-04-01
Filing date: 2011-09-01
Publication date: 2013-12-11
Anticipated expiration: 2031-09-01
Also published as: JP2012216102A; WO2012137367A1; WO2012137368A1; GB201316192D0; GB2502922B

Abstract

[Problem] The purpose of the present invention is to provide an imaging device that can efficiently record video data between a plurality of imaging devices or between an imaging device and a recording device. [Solution] A video monitoring system provided with an imaging device (1-1 to 4-4) disposed in a railroad car or the like, a network switch (W1 to w4), a video display device (H1, H2), a management device (K), and other components, wherein the conditions inside a vehicle are monitored by video, the video data is recorded in a recording medium mounted installed in the imaging device, and a recording medium of another imaging device is shared in order to optimize the interval for replacing the recording medium or removing the video data.

Description

IMAGING DEVICE, MANAGEMENT DEVICE,

AND VIDEO MONITORING SYSTEM

Field of the Invention

The present invention relates to an imaging device for recording video data therein and transmitting the video data to another imaging device via a network, a management device for managing the imaging device, and a video monitoring system.

Background of the Invention

Recently, an operation of a video monitoring system in a railroad vehicle has been examined. The video monitoring system including an imaging device, a network switch and an image display device monitors conditions inside the vehicle through video and records video data in a recording medium installed in the imaging device.

Patent Document 1: Japanese Patent Application Publication No. 2010-028754 A conventional imaging device is disadvantageous in that when video data is recorded in a recording medium installed in the imaging device, excessive video data cannot be recorded in the recording medium due to a small recording capacity of the recording medium, or the storage time of the video data is shortened due to overwriting.

Summary of the Invention

In view of the above, the present invention provides an imaging device capable of effectively recording video data among a plurality of imaging devices or between an imaging device and a recording device, a management device for managing the imaging device, and a video monitoring system.

In accordance with an aspect of the present invention, there is provided an imaging device including: an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined image processing on the video signal to output video data; a recording unit configured to record the video -1 -1-4n,c, ,n44 rI 4,--.-' -4h A LC p *.__) S'._!._4_LJ4 _.. L. L_)1___!._Ci LJ\LULSLLLiiI__'_OLC W_I_ Lii an external device; and a control unit configured to control the units. The control unit transmits the video data to the external device when the recording unit has no spare capacity and records video data in the recording unit when the video data is received from the external device.

The control unit may check spare capacities of recording units in other imaging devices and sets a recording reservation area for recording the video data in a part of the spare capacity of the recording unit in each of said other imaging devices based on the checked result.

The control unit may set the recording reservation area based on a current average recording amount and a current spare capacity of the recording unit in each of said other imaging devices and set a priority of said other imaging devices as transmission destinations.

The control unit may set said other imaging devices as the transmission destinations to which the video data is transmitted.

In accordance with another aspect of the present invention, there is provided a management device monitoring recording states of recording units in a plurality of imaging devices through a network and controls video data acquired by an imaging device having no spare capacity to be transmitted to one or more imaging devices having spare capacities.

The management device may set recording reservation areas for recording the video data, which is acquired by the imaging device having no spare capacity, in parts of the spare capacities of recording units in the respective imaging devices having the spare capacities based on the recording states of the recording units in the plurality of the imaging devices.

The management device may set the recording reservation areas based on current average recording amounts and current spare capacities of the recording units in the imaging devices having the spare capacities, and, among the imaging devices having the spare capacities as transmission destinations, the priority for transmitting the video data thereto may be set in the order of sizes of recording S reservation areas in the imaging devices having the spare capacities.

The management device may set a group of the imaging devices to which the video data is transmitted.

In accordance with still another aspect of the present invention, there is provided a video monitoring system including: a plurality of imaging devices, each of which has: an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined video processing on the video signal to output video data; a recording unit configured to record the video data; a communications unit configured to .jl -...._.1_-.._.__. 1:-..-. ...4 _.

WSLA1 all XLtr1LaJ. CVSLC. chic.,, a LO1.ILLL).L uiilL configured to control the units; and a management device configured to monitor and control spare capacities of recording units in the imaging devices through a network.

The management device makes the video data acquired by an imaging device having no spare capacity to be transmitted to other imaging devices having spare capacities.

In accordance with still another aspect of the present invention, there is provided a video monitoring system including: a plurality of imaging devices, each of which has: an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined video processing on the video signal to output video data; a recording unit configured to record the video data; a communications unit configured to communicate with an external device; and a control unit configured to control the units; and a management device configured to monitor and control spare capaciLLes of recording units of the imaging devices through a network.

The control unit transmits the video data to the external device when the recording unit has no spare capacity, and records video data in the recording unit when the video data is received from said another imaging device.

Effects of the Invention The video data can be effectively recorded by sharing a recording area among a plurality of different imaging devices or between an imaging device and a recording device based on the recording states of the imaging devices.

Brief Description of the Drawings

Figs. 1A and lB show a configuration of a railroad vehicle in which imaging devices in accordance with an embodiment of the present invention are installed, and -5.-address tables of devices, Fig. 2 depicts an example of a configuration of the imaging device in accordance with the embodiment of the present invention.

Fig. 3 illustrates an example of an arrangement of the imaging devices and respective views thereof in accordance with the embodiment of the present invention.

Fig. 4 presents recording capacities of the imaging devices in accordance with the embodiment of the present invention.

Fig. 5 shows a configuration of a railroad vehicle in which recording devices and imaging devices in accordance with an embodiment of the present invention are installed.

Fig. 6 depicts video recording states on a vehicle basis in the imaging devices in accordance with the embodiment of the present invention.

Fig. 7 presents video recording states on a device basis in the imaging devices in accordance with the embodiment of the present invention.

Fig. 8 shows relational equations and recording reservation states of the imaging devices in accordance with the embodiment of the present invention.

Fig. 9 depicts an example of movement of a recording process during recording area sharing in the imaging devices in accordance with the embodiment of the present invention.

Fig. 10 illustrates another example of movement of a recording process during recording area sharing in the imaging devices in accordance with the embodiment of the present invention.

Figs. hA and 113 depict a signal diagram of an example of a recording operation of the imaging devices by sharing recording areas in accordance with the embodiment of the present invention.

Figs. 12A and 123 depict the signal diagram showing the example of the recording operation of the imaging devices by sharing the recording areas and a process of switching a destination imaging device in accordance with the embodiment of the present invention.

Fig. 13 presents an example of an imaging device grouping process of the imaging devices in accordance with the embodiment of the present invention.

Detailed Description of the Embodiments

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment) A first embodiment in accordance with the present invention is a video monitoring system including an imaging device, a network switch, a video display device, and a management device which are installed in a railroad vehicle or the like. The video monitoring system video monitors conditions inside a vehicle and records video data in a recording medium installed in the imaging device. The video monitoring system records the video data while effectively using a small capacity of the recording medium installed in each imaging device.

Figs. lA and lB show a configuration of a railroad vehicle in which a plurality of imaging devices in accordance with an embodiment of the present invention is installed and address tables of devices, respectively. The plurality of imaging devices in accordance with the embodiment of the present invention is installed in, e.g., a railroad vehicle and is connected to a network such as a LAN, a WAN or the like through wired or wireless communications.

As a consequence, a video monitoring system is constructed and effectively operated.

In detail, referring to Fig. LA, in a railroad vehicle -, c-,-- ml -, C.-.--,--i--h.-_l.-mn ct.1_A_I_S _ vCLL_LLSC.1.1. !_OaLs._)t_h.I_Lsiv CLAA-L4_C £ l cli. C connected to one another, the first vehicle Tl includes imaging devices 1-1 to 1-4, a video display device Hi, a management device K, a vehicle device 9 connected to the management device K and a switch Wi. The imaging devices 1-1 to 1-4, the management device K and the video display device ill are connected to the switch Wi.

The imaging devices 1-1 to 1-4, the video display device Hi, and the management device K of the first vehicle Ti are allocated with several unique IP address in a network

-B-

group of, e.g., 192.168.1.0/24.

Similarly, the second vehicle T2 includes imaging devices 2-1 to 2-4, and a switch W2. The imaging devices 2-1 to 2-4 are connected to the switch W2. The imaging devices 2-1 to 2-4 of the second vehicle T2 are allocated with several unique IF address in the network group of, e.g., 192.168.1.0/24.

Similarly, the third vehicle T3 includes imaging devices 3-1 to 3-4 and a switch W3. The imaging devices 3-1 to 3-4 are connected to the switch W3. The imaging devices 3-1 to 3-4 of the third vehicle T3 are allocated with several unique IF address in the network group of, e.g., 192.168.1.0/24.

Similarly, the fourth vehicle T4 includes imaging devices 4-1 to 4-4, a video display device H2, and a switch W4. The imaging devices 4-1 to 4-4 are connected to the switch W4. The imaging devices 4-1 to 4-4 and the video display unit H2 of the fourth vehicle T4 are allocated with several unique IF address in the network group of, e.g., 192.168.1.0/24.

The vehicles are connected to other vehicles adjacent thereto at the switches. The management device K acquires and renews the IF addresses of all the devices in each vehicle (the first vehicle Ti, the second vehicle T2, the third vehicle T3, and the fourth vehicle T4) in advance or when necessary, and manages the IF addresses as database -9-.

shown in Fig. lB. The management device K monitors conditions of the devices in the vehicle or instructs various commands. Further, the management device K instructs commands to the devices in the vehicle based on a signal transmitted from the video display device Hi or H2 by manipulation of a crew member.

The vehicle device 9 exchanges various information on vehicles or operations with a communications unit or a management center provided outside a railroad vehicle, e.g., at a station through wired or wireless communications. Here, various information includes, e.g., vehicle composition information, train diagram information, information on doors to be opened at each station, and the like.

A crew member specifies vehicle number, rimaging device number/namej or the like in order to check a live video of an imaging device of a specific vehicle by using a 4 4_..-41 _. A_4-.- k. -A-. -14 -..-1 A.--..-1 nl VSLICLJ LAV.LL. LILt V.Lt.AL) LACVJLC flJ and H2 search the database managed by the management device for an IP address of the object imaging device based on the specified information. Next, the video display devices are connected to the object imaging device based on the IP address. The video display devices acquire the live video to display the acquired live video on its display portion.

A crew member specifies recording device nurnber/nameu, vehicle numberi or rimaging device number/namej rtime and date of recorded videoj or eventj, and the like in order to check a recorded video of an imaging device of a specific vehicle by using the video display devices Hi and H2. Then, the video display devices Hi and H2 search the database managed by the management device for an IF address of the object imaging device based on the specified information. Next, the video display devices are connected to the object imaging device based on the IF address. The video display devices acquire video data recorded in the recording medium installed in the imaging device to display the reccrded video on its display portion. The recording medium installed in the imaging device has a format of a detachable SD card or the like.

Therefore, the recording medium can be detached from the imaging device and connected to a personal computer or the is iike so that the recorded video can be checked.

Fig. 2 presents an example of a configuration of the imaging device in accordance with the embodiment of the present invention.

The imaging device includes: a control unit 11 for controlling an entire operation of the imaging device; an imaging element 12 (i.e., imaging unit) such as a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) or the like for receiving light from an imaging object and outputting a video signal; a video processing unit 13 for performing video processing or various conversion processing on the video signal outputted -ii-from the imaging element 12; a recording unit 14 having the recording medium such as an SD card or the like which can be detachably attached; and a communications unit 15 for performing wired or wireless communications.

The imaging element 12 generates a video signal by performing photoelectric conversion on incident light in an imaging area and outputs the video signal to the video processing unit 13. En the video processing unit 13, the video signal is subjected to video processing or various conversions processing under the instruction of the control unit 11. The video data is outputted to the recording unit 14 or the communications unit 15. The recording unit 14 records the video data therein and, when necessary, the recording unit 14 outputs the video data to the communications unit 15 under the instruction of the control unit 11. The communications unit 15 communicates with the 4-n,. 1 1,-, 1-1 L_JIAL.SLLCL).L LILC SkLL\ .4. LL.J.A V * £110 __LJLlL1LLLflJ L'_.QL.LLJLJoL4LJsL.s.J transmits the video data whose format has been converted in accordance with types of transmission paths, or receives a signal from the outside.

A general recording process of the imaging device configured as described above and the monitoring system provided at a railroad vehicle including the imaging device will be described hereinafter. Fig. 3 illustrates an example of an arrangement of the imaging devices and respective views thereof in accordance with the embodiment of the present invention. Figs. 4A to 4C depict recording capacities of the imaging devices. Fig. 5 presents a configuration in a railroad vehicle in which the imaging devices and the recording devices are installed. Fig. 6 shows video recording states on a vehicle basis in the imaging devices. Fig. 7 presents video recording states on a device basis in the imaging devices.

In the first vehicle Ti shown in Fig. 3, the imaging devices 1-1 to -3 monitor conditions in a vehicle by video and, at the same time, video data is recorded in the recording medium installed in the imaging device. The imaging device 1-1 is operated such that the door opening/closing video is recorded when the information on opening and closing of the door 22 is notified. In the same manner, the imaging device 1-2 and the imaging device 1-3 record images when the information on opening and closing of doors 21 and 23 are specified, respectively. Here, the opening and closing of the doors may be specified to the imaging devices from sensors provided at the doors, or may be specified to the imaging devices from the management device K. Alternatively, the opening and closing of the doors may be detected from the acquired video. The imaging device 1-3 records video based on the door opening/closing states in a train which vary depending on boarding of passengers or movement of passengers between vehicles. Therefore, the frequency of opening and closing of the door 23 and the video recording frequency for the door 23 are set to be highest in this case. When a train reaches a station, the doors 22 and 23 are opened and closed for boarding of passengers. At this time, the frequency of opening and closing of the door 22 and the video recording frequency for the door 22 are set to be higher, whereas the frequency of opening and closing of the door 21 and the video recording frequency for the door 21 are set to be lower in this case.

When the monitoring system is operated in the above-described conditions, the imaging device 1-3 shown in Fig. 4C among the imaging devices 1-i to 1-3 firstly reaches the maximum recording capacity of the recording medium installed in the imaging device, as shown in Figs. 4A to 4C. In that case, it is generally required to clear the recorded data in the recording medium by separating the recording medium from A,.-A anL.LASS LCJ____1_1l'J ncw.L CL.L)L LA_LiI JUcL_L_LLiitt by downloading the recorded video data from the imaging device through remote control from a management center or the like.

The problem in which the recordable period of the recoded data is short due to a small capacity of the recording medium installed in the imaging device can be solved by providing the recording device at each of the first to the fourth vehicles Ti to T4 as shown in Fig. 5 or by providing a recording device at a front vehicle. However, it is difficult to install an additional recording device in a limited space such as the inside of a train, and the system purchasing cost is increased.

The recording medium installed in the imaging device is, e.g., an SD card or the like, and the capacity thereof is generally about a few MB to 32 GB. Thus, the video may be constantly recorded in a single recording medium at a frame rate of about 2 bo 3 frames/sec and about 3 to 4 days' amount of video data may be stored. In that case, it is required to exchange recording mediums or remove video data at a high frequency of once every 3 to 4 days.

When the video is recorded at a low frame rate of about 1 to 2 frames/sec, the video may be scored in the imaging device for about 4 to 5 days. However, when abnormality occurs in a vehicle and the recorded video needs to be checked, most important video may have not been recorded due to a low frame rate.

The recording type includes an event (alarm) recording.

For example, the imaging device 30 normally captures images at a low frame rate and records video at a high frame rate only when the information on the opening and closing of the door 34 is notified. Accordingly, video may be recorded only when an event such as entrance and exit of a person occurs, and video may be not recorded when no change occurs.

As a result, video can be effectively recorded while effectively using a limited recording capacity.

However, even in the case of the event (alarm) recording, the imaging devices have different event (alarm) recording amounts of video data, as shown in Fig. 4.

Therefore, it is still required to check video data by exchanging recording mediums or removing the video data (download) at different intervals on an imaging device basis.

In the following description, the interval of checking the video data by exchanging the recording mediums or removing the video data is referred to as check intervali The embodiment of the present invention is characterized in optimizing check intervaL First, the check interval may be set to rvehicle uniti. As shown in Fig. 6, the video data is checked by exchanginq recording mediums or removing data of all the imaging devices at the check interval of the imaging device having a largest recording amount (e.g., the imaging device j*) Li! L11Lb The check interval of vehicle uniti or train composition uniti is realized in the following manner. One of the imaging devices manages a recording amount of a recording unit thereof and recording amounts of other imaging devices in the same vehicle by monitoring.

Alternatively, the management device K manages recording amounts of the imaging devices of the entire vehicles by monitoring. The interval of the imaging device having the largest recording amount is determined to be rcheck interval on a vehicle unitj or rcheck interval on a train composition unitj. Further, the timing of downloading the video data or exchanging the recording mediums is notified from the vehicle device 9 to the management center via the network under the control of the management device K. In this method, the check interval is simply determined and the recording mediums can be exchanged or the video data can be downloaded at rcheck intervalj in an integrated way, so that work loads of an operator can be reduced. On the other hand, the recording medium of the imaging device 1-2 which has a low use frequency is not effectively used.

Next, the check interval may be set to imaging device unit.j. As shown in Fig. 7, the video data is checked by exchanging the recording mediums of the imaging devices or removing the video data at the respective check intervals of the imaging devices.

The check interval of rimaging device uniti is realized in the following manner. The control units 11 of the imaging devices manage the recording amounts of the recording units 14 by monitoring. Further, the timing of downloading the video data or exchanging the recording mediums is notified from the vehicle device 9 to the management center via a network under the control of the management device K. In such operation of the imaging device unit, the recording capacity can be more effectively used compared to the aforementioned rcheck interval on a vehice unitj and rcheck interval on a train composition unitj. However, in some cases, the recorded video data is downloaded from the imaging device or the recording medium is separated from any one of the imaging devices in a daily basis to check the video data, which requires a lot of work loads of an operator.

Next, the method of using the recording area of each imaging device (hereinafter, referred to as "recording schedule") needs to be considered to obtain a proper check interval' in sharing the recording capacity between the imaging devices in accordance with the embodiment of the present invention. As shown in Figs. B to 12, the recording capacities of the imaging devices can be effectively utilized by using a recording area of an imaging device having a spare capacity as a recording area of an imaging device having no spare capacity among a plurality of imaging devices. This will be described in detail with reference to the drawings. In the present embodiment, in order to obtain proper check interval', the recording schedule is calculated based on the average recording amount or the current recording amount of each imaging device. The recording schedule enables the recording capacity to be used most effectively by determining a recording medium of an imaging device to which video acquired by a certain imaging device will be transmitted and the downloading of the video data or the replacement of the recording medium to be executed at a long interval and at the same timing.

In the present embodiment, as shown in Figs. hA to l2B, when the imaging device 1-3 receives event information or detect an event such as opening/closing of the door 23 in a train or the like (step 311), it is checked whether or not the recording capacity of the recording unit 14 in the imaging device 1-3 has an enough space. When the recording capacity has the enough space, the recording is continued.

Otherwise, a command is transmitted from the communications unit 15 to other imaging devices 1-1 and 1-2 via the network to make the imaging devices 1-1 and 1-2 to confirm the recording states (recording amounts and/or spare capacities) of the recording mediums therein (step S12) The imaging devices 1-1 and 1-2 that have received the command notify the information on the usage amount of the recording medium, the spare capacity, the recording start time or the like to the imaging device 1-3 (steps S13 and 314) . The imaging device 1-3 analyzes the states of the imaging devices based on the received information, obtains the recording reservation areas of the imaging devices by calculating the recording schedule, determines the priority of the imaging devices where the data will be transmitted and recorded, and transmits a command for ensuring the recording reservation area to the object imaging devices 1-1 and 1-2 (step S15) The analysis method and the method for calculating the recording schedule will be described in detail later. Here, the recording reservation area indicates a recording area that is set in a recording medium of another imaging device so that excessive video acquired by an imaging device having no spare recording capacity can be transmitted to and recorded in the another imaging device.

The imaging devices 1-1 and 1-2 that have received the command set the recording reservation areas in parts (indicated by A and B in Fig. 8) of the recording areas of the recording mediums used for recording the excessive video of the imaging device 1-3 and transmit the preset information data to the imaging device 1-3, respectively (steps S16 and 517) Next, the imaging device 1-3 receives the event information data or detects the event such as the opening and closing of the door 23 in a train (step S18) -Then, the imaging device 1-3 transmits the acquired video data and a command for recording the video data in the recording reservation area B to the imaging device 1-2 having a highest priority based on the priority (step 519) . When the video data and the command are received from the imaging device 1-3, the imaging device 1-2 records the video data from the imaging device 1-3 in the recording reservation area B set in the recording medium thereof, checks the spare capacity after the recording, and notifies the normal completion of the recording of the video data to the imaging device 1-3 (step 520) . At this time, the imaging device 1-2 also records the acquired video data in the recording medium thereof based on the event information such as the opening and closing of the door 21 or the like.

The video data at this time or the video data to be recorded later may be transmitted from the imaging element 12 to the communications unit 15 via the video processing unit 13, or may be recorded first in the recording unit 14 and then read out to be transmitted.

The processes from the step 518 to the step 520 in which the video data acquired by the imaging device 1-3 is transmitted to and recorded in another imaging device 1-2 are continued until the recording reservation area in the imaging device 1-2 becomes full. As shown in Figs. 12A and 12B, after completion of the event notification in step 521 and the video data transmission in step 319, the imaging device 1-2 that has received the video data and the command records the received video data in the recording reservation area thereof and checks the spare capacity of the recording reservation area. Jhen it is determined that the spare capacity does not exist or is small, information on the no spare capacity or the small capacity is notified together with the normal completion of the recording of the video data to the imaging device 1-3 (step 523) . The state at this time is shown in Fig. 9. Based on this notification, the imaging device 1-3 changes the video data transmission destination to the imaging device 1-1 having a second highest priority in accordance with the priority determined in the step 515 (step 524) When the event such as the opening and closing of the door 23 in a train is detected or the event information is received (step 525), the acquired video data and a command for recording the video data in the recording reservation area A are transmitted to the imaging device 1-2 having a second highest priority based on the priority (step 326) -When the video data and the command from the imaging device 1-3 are received, the imaging device 1-1 records the video data from the imaging device 1-3 in the recording reservation area A set in the recording medium thereof, checks the spare capacity after the recording, and notifies the normal completion of the recording of the video data to the imaging device 1-3 (step 327) . At this time, the imaging device 1-1 also records its own acquired video data in the recording medium thereof based on the event information such as the opening and closing of the door 22 or the like.

As in the case of the imaging device 1-2, the processes from the step 525 to the step 527 in which the video data acquired by the imaging device 1-3 is transmitted to and recorded in another imaging device 1-1 are continued until the recording reservation area of the imaging device 1-1 becomes full. The imaging device 1-2 checks the spare capacity of the recording reservation area during the repetition of such operations. When it is determined that the spare capacity does not exist or is small, information on the no spare capacity or the small capacity is notified together with the normal completion of the recording of the video data to the imaging device 1-3. The state at that time is shown in Fig. 10.

Based on this notification, the imaging device 1-3 changes the video data transmission destination to an imaging device having a next high priority in accordance with the priority determined in the step SiS.

When the recording capacities of the recording mediums of all the imaging devices become full by repeating the above processes, the necessity of downloading the video data or replacing the recording mediums is notified to the management center or the like. Preferably, the necessity of downloading the video data or exchanging the recording mediums is notified to the management center together with the information on the predicted timing at which the recording capacities of the recording mediums become full before the recording capacities of the recording mediums of all the imaging devices become full.

Hereinafter, the recording schedule calculation method and the analysis of the states of the imaging devices in step S15 will be described in detail with reference to Fig. 8.

First, an average recording amount of an imaging device is calculated from the recording amount and the recording start schedule recorded in the recording medium.

Then, the priority is set in the order of imaging devices having recording mediums of a larger spare capacity and a smaller average recording amount. Next, the recording schedule is calculated from the average recording amounts of the imaging devices and the spare capacity of the recording mediums of the imaging devices.

The recording schedule may be obtained based on the contents (recording start date and usage amount) recorded in the recording medium, or may be statistically obtained from updated contents recorded. Preferably, the average recording amount can be updated from the system introduction date or based on the recorded contents every day or at the check interval if samples can be obtained since the

introduction of the system.

In other words, in order to obtain the proper check interval', the recording schedule is algebraically calculated in such a manner that (spare recording capacity of the imaging device 1-i recording reservation capacity of the imaging device 1-3)/average recording amount of the imaging device 1-1, (spare recording capacity of the imaging device 1-2 -recording reservation capacity of the imaging device 1-3)/average recording amount of the imaging device 1-2, and (recording reservation capacity of the imaging device 1-3 which is ensured in the imaging device 1-i + recording reservation capacity of the imaging device 1-3 which is ensured in the imaging device 1-2)/average recording amount of the imaging device 1-3 become substantially the same, as shown in the lower part of Fig. 8.

Here, on the assumption that spare recording capacity of the imaging device 1-1 -recording reservation capaciLy of the imaging device 1-3' is C; spare recording capacity of the imaging device 1-2 -recording reservation capacity of the imaging device 1-3' is D; recording reservation capacity of the imaging device 1-3 which is ensured in the imaging device 1-1' is A; and recording reservation capacity of the imaging device 1-3 which is ensured in the imaging device 1-2' is B, the equation can be simply expressed by C/ (average recording amount of the imaging device i-i) 0/ (average recording amount of the imaging device 1-2) A+B/ (average recording amount of the imaging device 1-3) In the first embodiment, the recording schedule is calculated to obtain the proper check interval' based on the above equation, and the transmission process is performed based on the recording schedule. As a consequence, the video monitoring system can be most effectively operated.

In the present embodiment, the recording schedule is calculated by the imaging device 1-3 of which recording capacity becomes full most quickly. However, a reference imaging device may be set on a group basis and, then, the reference imaging device may monitor the recording states of other imaging devices or calculate the recording schedule.

(Second embodiment) The second embodiment has a purpose of setting a range of imaging devices as transmission destinations, i.e., integrating image devices to share recording areas (to set recording reservation areas) , in the case of transmitting video data to another imaging device in the first embodiment.

In other words, it is determined whether imaging devices of all the vehicles will be used as the transmission destinations, whether imaging devices of the same vehicle will be used as the transmission destinations, whether imaging devices of a plurality of vehicles will be used as the transmission destinations, or whether imaging devices integrated based on specific conditions (e.g., grouping of imaging devices installed in the same location of the respective vehicles or the like) will be used as the transmission destinations. Here, the recording schedule is obtained and operated on an imaging device integration (group) basis.

Here, the case in which the imaging devices are grouped on a vehicle basis will be described as an example.

Hereinafter, a process of setting a group of the imaging devices will be referred to as 1groupingj The grouping may be set by manipulating an imaging device main body, or may be set on a manipulation screen of a laptop connected to the imaging device. Further, the grouping may be set by using the management device and the video display device, or may be set from the management center via the vehicle device.

Mere, the grouping is performed in such a manner that a crew member displays the manipulation screen shown in Fig. 13 by manipulating the management device K through the video display device Ml.

A list of imaging devices installed in the composition vehicles with IP addresses is displayed on the screen of the video display device Ml as shown in (a) of Fig. 13, and the imaging devices 1-1 to 4-4 are classified into a desired group by manipulation. When the imaging devices are grouped in a plurality of groups, the list of the imaging device with IP addresses is displayed as shown in (b) of Fig. 13.

Here, the imaging devices are grouped on a vehicle basis.

The management device K stores this setting as the management information, and the group information is transmitted to the imaging devices. The recording schedule described in the first embodiment is calculated and executed by the imaging devices based on the group information.

By setting a grouping rule in advance in the imaging devices (e.g., grouping the imaging devices in the same vehicle), the operator's manipulation becomes unnecessary, and the manipulation tine can be omitted.

Further, the management device K may automatically perform ideal grouping (combination of imaging devices which can utilize the recording capacity most effectively) . In that case, the imaging devices are grouped such that the ratio of the collected average recording amounts of the imaging devices becomes uniform, and the recording reservation areas are set in advance. Accordingly, the manipulation time can be omitted, and the recording capacity can be more effectively used.

(Third embodiment) In the above-described embodiments, the imaging device calculates the recording schedule and the priority based on the grouping. However, in the present embodiment, the management device K calculates the recording schedule and performs entire management.

In other words, in the first embodiment, the imaging device sets the recording reservation areas by checking the spare capacities of other imaging devices and determines the priority of the processes, but, in the present embodiment, the management device K executes such processes. This will be described in detail below with reference to Fig. 1.

However, the configuration of the third embodiment is the same as that of the above embodiments, so that the description thereof will be omitted. When the management device K communicates with each device, a signal is transmitted and received via the switch unit N. In the communications with each device, only the first passage of the signal through the switch(s) will be described, and the description on the subsequent passage of the signal through the switch(s) will be omitted. Here, the imaging device 1-1 of the first vehicle, the imaging device 2-2 of the second vehicle, the imaging device 3-S of the third vehicle and the imaging device 4-4 of the fourth vehicle which are installed at different locations in the respective vehicles are grouped (the first group in the present embodiment by an example) Moreover, the recording amount is largest in the order of the imaging device 1-1, the imaging device 1-2, the imaging device 1-3 and the imaging device 1-4.

The imaging devices perform imaging and recording in accordance with the door opening/closing information, and the management device K monitors the recording states of the imaging devices. Specifically, in the first group, the managing device K transmits the commands, which make the imaging devices to check the recording amounts and to return the check results, to the imaging device 1-1 via the switch Wl, to the imaging device 2-2 via the switches Ni and W2, to the imaging device 3-3 via the switches Wi to W3, and to the imaging device 4-4 via the switches Ni to W4. The imaging devices that have received the commands check the currently recording amounts thereof and transmit the recording state information to the management device K. The management device updates the received recording states of the imaging devices.

When the spare capacity of the imaging device having the largest recording amount becomes reduced to about 1/2, 1/3 or the like, the management device K obtains the recording schedule based on the current spare capacities of the other imaging devices and the average usage amounts of the imaging devices, determines the priority, and sets the recording reservation areas in the target imaging devices.

when the imaging device having the largest recording amount has no spare capacity, the video data is transmitted to another imaging device in accordance with the priority.

Here, unlike the first embodiment, the recording schedule is not calculated when the recording capacity becomes full.

This is because the management device K manages all the groups and the load concentration caused by the overlapping of the recording schedule calculation timing should be prevented. However, as in the first embodiment, the recording schedule may be calculated when the recording capacity becomes full.

Specifically, when the spare capacity of the imaging device 1-1 becomes small while monitoring the recording states of the imaging devices, the management device K calculates the recording schedule based on the recording states of the other imaging devices and the average usage amounts and determines the priority. At this time, the priority is set in the order of the low recording amount, i.e., in the order of the imaging device 4-4, the imaging device 3-3, and the imaging device 4-2. Further, the management device K transmits the commands for setting the recording reservation areas to the imaging devices 4-4, 3-3 and 4-2, and the imaging devices 4-4, 3-3 and 4-2 set the recording reservation areas in the recording areas thereof in accordance with the commands. When the imaging device 1- 1 has no spare capacity, the management device K transmits the command to the imaging device 1-1 so that the video data can be transmitted to the imaging device 4-4 having a highest priority. The imaging device 1-1 transmits the video data to the imaging device 4-4 in accordance with the command, and the imaging device 4-4 records the received video data from the imaging device 1-1 in the recording reservation area thereof.

A second and a third imaging device having no spare capacity may appear in the group. In that case, a recording reservation area is preferably reset in an imaging device for substitutable recording other than the imaging device to which the video data has been recorded for substitution from the imaging device having no spare capacity.

Specifically, when the spare capacity of the imaging device 2-2 is further reduced, the recording schedule is calculated based on the recording states of the other imaging devices and the average usage amounts. The management device K transmits a command to the imaging device 3-3 so that the recording reservation area for the imaging device 2-2 can be set by omitting or reducing the recording reservation area for the imaging device 1-1 based on the average usage amount or the like, The imaging device 3-3 resets the recording reservation area in the recording area thereof in accordance with the command.

When the imaging device 2-2 has no spare capacity, the management device K transmits a command to the imaging device 1-1 so that the video data can be transmitted to the imaging device 4-4. The imaging device 1-1 transmits the video data to the imaging device 4-4 in accordance with the command, and the imaging device 4-4 records the received video data from the imaging device 1-1 in the recording reservation area thereof. At this time, the imaging device 4-4 records the video data from the imaging device 1-1 for substitution and thus does not record the video data from the imaging device 2-2. However, when the number of imaging devices is great in the group and an imaging device having a spare capacity for substitutable data recording exists in the group, the recording reservation area is set and the priority is determined.

When the recording reservation area for the imaging device 1-1 which is set in the imaging device 4-4 becomes full as a result of the recording of the video data in its own device and the substitutable recording of the video data from other devices, the management device K allows the imaging device 1-1 to record the video data in the recording reservation area for the imaging device 1-1 which had been reset to be reduced in the imaging device 3-3. Therefore, the command for transmitting the video data to the imaging device 3-3 is transmitted to the imaging device 1-1. The imaging device 3-3 records the video data transmitted from the imaging device 2-2 in the recording reservation area for the imaging device 2-2 and records the video data transmitted from the imaging device 1-1 in the recording reservation area for the imaging device 1-1 in accordance with the command.

Then, when the recording capacities of the recording mediums of all the imaging devices become full, the necessity of replacing the recording mediums or downloading the video data is notified to the management center or the like. Preferably, the necessity of replacing the recording mediums or downloading the video data is notified to the management center or the like together with the information on the predicted timing at which the recording capacities of the recording mediums become full before the recording capacities of the recording mediums of all the imaging devices become full. Therefore, the exchange of the recording mediums or the removal of the video data is performed during night time at which a train does not operate.

The management device manages and controls the recording states and the recording schedule of all the imaging devices in the integrated way, so that the management and the operation of the monitoring system become easy. As a result, the entire system can be effectively operated.

However, the recording capacities of all the imaging devices in the group may become full when the exchange of the recording mediums or the removal of the video data cannot be carried out during operation of a train or the like. When the recording mediums cannot be exchanged, a spare capacity of an imaging device in another group is checked. If there is an imaging device having a spare capacity, the video data is recorded in that imaging device.

If the video data cannot be removed, the excessive video data is recorded in a recording medium, e.g., HDD (Hard Disk Drive) , SSD (Solid State Drive) or the like, provided at the management device K or recorded in an additional recording device.

when the recording capacities of the imaging devices in the group are full, the management device K for monitoring and managing the recording states of the imaging devices in all the groups checks whether or not an imaging device having a spare recording area exists in another group.

When such imaging device exists, the recording reservation area is reset in such imaging device, and the excessive video data is transmitted to such imaging device. when an imaging device having a spare recording area does not exist in another group and the recording capacities of all the imaging devices are full, the recording reservation area of the excessive video data is set in an additional recording device or the recording medium of the management device, and a command for transmitting video data to such recording device or the recording medium of the management device K is transmitted to each camera. Each camera transmits the video data to the recording device or the management device K in accordance with the command. The recording device or the management device K records the video data in the recording reservation area therein, Accordingly, when the exchange of recording mediums or the removal of video data during operation of a train cannot be executed, the video data recording and the monitoring operation can be continued despite that the recording capacities of all the imaging devices in the group become full.

In accordance with the present invention, the frequencies of exchanging recording mediums, removing video data, and checking operation can be decreased. As a consequence, the operating time of the monitoring system can be shortened.

In the imaging device, when the event is detected, the compression ratio of the video data during the recording becomes low. When the event is not detected, the compression ratio of the video data can be high.

Accordingly, the video data amount can be decreased and, further, the check interval can be lengthened.

The event is not limited to the opening and closing of the door, and may also be, e.g., face detection of an imaging object, fire detection, pressing of an emergency button or the like.

The above-described embodiments can be implemented at the same time. Those skilled in the art can realize the present invention by various embodiments -described above, and further can easily invent various modifications of these embodirnenus and can apply them to various embodiments without inventive ability. Therefore, the present invention covers a wide range which -s not contradictory to a disolosod principle and novel characteristics, and is not limited to the above embodiments.

Industrial Applicability

In a video monitoring system including a video display device, a network switch and an imaging device having a recording medium, video data can be effectively recorded while sharing recording areas among a plurality of imaging devices or recording devices based on recording states of a plurality of imaging devices.

Description of Reference Numerals

1-i to 4-4 imaging device Hi, H2 video display device K management device Wi to W4 switch ii control unit 12 imaging device 13 video processing unit 14 recording unit communications unit

Claims

What is claimed is: 1. An imaging device, comprising; an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined image processing on the video signal to output video data; a recording unit configured to record the video data; a communications unit configured to communicate with an external device; and a control unit configured to control the units, wherein the control unit transmits the video data to the external device when the recording unit has no spare capacity and records video data in the recording unit when the video data is received from the external device.
2. The imaging device of claim 1, wherein the control unit checks spare capacities of recording units in other imaging devices and sets a recording reservation area for recording the video data in a part of the spare capacity of the recording unit in each of said other imaging devices based on the checked result.
3. The imaging device of claim 2, wherein the control unit sets the recording reservation area based on a current average recording amount and a current spare capacity of the recording unit in each of said other imaging devices and sets a priority of said other imaging devices as transmission destinations.
4. The imaging device of any one of claims 1 to 3, wherein the control unit sets said other imaging devices as the transmission destinations to which the video data is transmitted.
5. A management device which monitors recording states of recording units in a plurality of imaging devices through a network and controls video data acquired by an imaging device having no spare capacity to be transmitted to one or more imaging devices having spare capacities.
6. The management device of claim 5, wherein the management device sets recording reservation areas for recording the video data, which is acquired by the imaging device having no spare capacity, in parts of the spare capacities of recording units in the respective imaging devices having the spare capacities based on the recording states of the recording units in the plurality of the imaging devices.
7. The management device of claim 6, wherein the management device sets the recording reservation areas based on current average recording amounts and current spare capacities of the recording units in the imaging devices having the spare capacities, and, among the imaging devices having the spare capacities as transmission destinations, the priority for transmitting the video data thereto is set in the order of sizes of the recording reservation areas in the imaging devices having the spare capacities.
8. The management device of any one of claims 5 to 7, wherein the management device sets a group of the imaging devices to which the video data is transmitted.
9. A video monitoring system comprising: a plurality of imaging devices, each of which includes: an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined video processing on the video signal to output video data; a recording unit configured to record the video data; a communications unit configured to communicate with an external device; and a control unit configured to control the units; and a management device configured to monitor and control spare capacities of recording units in the imaging devices through a network, wherein the management device makes the video data acquired by an imaging device having no spare capacity to be transmitted to other imaging devices having spare capacities.
10. A video monitoring system comprising: a plurality of imaging devices, each of which includes: an imaging unit configured to image an object and output a video signal; a video processing unit configured to perform predetermined video processing on the video signal to output video data; a recording unit configured to record the video data; a communications unit configured to communicate with an external device; and a control unit configured to control the units; and a management device configured to monitor and control spare capacities of recording units of the imaging devices through a network, wherein the control unit transmits the video data to the external device when the recording unit has no spare capacity and records video data in the recording unit when the video data is received from said another imaging device.