Wireless video transmission device and wireless video reception
Contents
1. tion devices is arranged so that upon detection of the infor mation as to the presence of a person the number of those communication channels usable for communication with the wireless video transmission device is reduced in such a man ner as to be less than the number of communication channels that are used before the detection This invention also provides a wireless video transmission device which wirelessly sends a video signal to a wireless video reception device This video transmission device is arranged to have a first standby mode which intermittently searches all communication channels to be used for wireless communication between the wireless video transmission device and the wireless video reception device in order to check or verify a startup request from the wireless video reception device and a second standby mode which intermit tently searches communication channels that are limited than those in the first standby mode In cases where a person exists transition is made to the second standby mode This invention also provides a wireless video transmission device which wirelessly sends a video signal to a wireless video reception device This transmission device is arranged to intermittently search for a communication channel to be used for wireless communication between the wireless video transmission device and the wireless video reception device in order to check a startup request from the wireless video reception device in a2. channels is set at 10 s or less As apparent from the foregoing description according to this embodiment when the radio video receiver device detects the presence of a person by using the human body detector control is provided to assign the limited communi cation channel candidates on a priority basis and simulta neously shorten the cycle of the intermittently performed startup request verification when compared to that in the normal standby mode thereby to achieve acceleration of the startup sequence In addition by searching all communica tion channels the startup sequence improves in stability even when the limited communication channel candidates become unusable due to a change in radio wave condition or the like Thus it becomes possible to avoid the occurrence of a mis match in power supply condition between the radio video receiver device and radio video transmitter device Although in the second embodiment a single communica tion channel is assigned within the second period 803 this is not to be construed as limiting the invention and may also be modified to assign two or more communication channels Embodiment 3 Next a third embodiment of this invention will be described with reference to FIGS 9A and 9B The third embodiment is different from the first embodiment in that a search is conducted with respect to every communication channel in the event of startup request verification in the specific standby mode in the
3. standby mode In a case a person is present this search time cycle is made shorter This invention also provides a wireless video reception device which receives a video signal that is wirelessly sent from a wireless video transmission device This reception device is arranged to force a radio unit s power supply to turn on in case a person is present while the radio unit power supply of the wireless video reception device is turned off According to this invention communication channel can didates for use between the wireless video transmission device and wireless video reception device are limited in number or alternatively the time cycle of the search for a communication channel is shortened when a person is present thereby making it possible to shorten the from standby startup time of the wireless video transmission and reception devices and also lessen the amount of electrical power to be consumed during standby thereof Other objects features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings BRIEF DESCRIPTION OF DRAWINGS FIG 1 is a flow chart of a processing operation of a device having a human body detection unit in accordance with one embodiment of this invention FIG 2 is a flowchart of a processing operation of a device operatively associated with the device having the human body detector unit in a
4. system in order to enable the radio video transmitter device 302 to receive the control command that was wirelessly sent from the radio video receiver device 306 it 1s necessary for the radio video transmitter device 302 to recognize a communication channel to be used by the radio video receiver device To do this within the standby time period in which any video audio signal is not being transmit ted the radio video transmitter device 302 searches as shown in FIGS 4A and 4B for example all available communication channels in the wireless system the total channel number is denoted by X within a time period T1 to thereby perform verification indicated by numeral 400 in FIG 4A of a star tup request for checking which one of the communication channels is used by the radio video receiver device 306 to send the control command At this time the radio video transmitter device intermittently performs the startup request verification 400 within this standby period in order to sup press power consumption in the standby period and retain it at alow level thereby forcing the radio video transmitter device 20 25 30 35 40 45 50 55 60 65 6 to almost stop its operation called the standby operation hereinafter while the startup request verification 400 is not performed 1 within a time period T2 In this way the radio video transmitter device is specifically arranged to repeatedly perform the startup
5. 17 In case no person is present transition is made to the normal standby mode at S108 On the other hand if a person is present a specific communication channel e g the commu nication channel that received the reply command from the radio video transmitter device at 5103 is used to transmit at 5107 to the radio video transmitter device a continuation command for instructing it to continue the above noted spe cific standby mode followed by judgment at S111 as to whether there is a reply command from the radio video trans mitter device in response to this continuation command If there is such reply the radio video receiver device per se continues the specific standby mode at S104 If there is no reply then transit to the normal standby mode at S108 Desirably the reply command is arranged to contain therein any one of the information for allowing the radio video transmitter device and radio video receiver device to limitthe communicable channel candidates information con cerning the number of those equipments existing within a communicable network information about the length of a time taken up to time out ofthe specific standby mode and a US 8 760 512 B2 9 signal indicative of the fact that the radio video transmitter device has received the command from the radio video receiver device The processing operations of the steps S102 S103 and 5109 5110 are also used for selection of the above stated usable communicat
6. 307 308 309 for example in particular on the front side ofthe display plane of the image display unit 10 and then supplies its detection signal to the CPU 14 A remote control RC light receiving unit 18 receives an RC signal from a remote controller not depicted which signal was generated by a user s manual operation of a remote controller for the radio video receiver device use and supplies it to the CPU 14 The CPU 14 analyzes the supplied header and control command and inputs the detection signal from the human body detection unit and the RC signal received by the RC light receiving unit to thereby generate a header and control command for con trolling the radio video transmitter device These header and control command are modulated by the modem unit 12 using a carrier for wireless transmission and then wirelessly sent from the transmitter receiver unit 13 to the radio video trans mitter device 302 by way of the antenna 15 Note that the human body detector unit 17 is the one that detects and judges whether a viewing person is present near the radio video receiver device and is constituted for example from either a human sensitive sensor such as an infrared sensor or an image pickup device such as a camera which is attached to a location around the image display unit 10 The human body detector 17 is modifiable to have an arrangement other than the one that directly detects a human body per se for example it may be arranged
7. NDBY STANDEY RECEIVER DETECTION DETECTION OPERATION OPERATON CPERATON RADIO VIDEO TRANSMITTER 400 CHECK STARTUP 401 401 401 401 401 STANDBY REQUEST STANDBY MODE AT SPECIFIC MODE NORMAL STANDBY MODE CHANNEL Chi Che F G 7 301 IMAGE DISPLAY PERSON DETECTOR RC LIGHT RECEIVER U S Patent Jun 24 2014 Sheet 6 of 7 05 8 760 512 2 m NS TIME TIME 802 803 802 803 802 803 U S Patent Jun 24 2014 Sheet 7 of 7 US 8 760 512 B2 FIG 9A TIME uS TIME US 8 760 512 B2 1 WIRELESS VIDEO TRANSMISSION DEVICE AND WIRELESS VIDEO RECEPTION DEVICE INCORPORATION BY REFERENCE The present application claims priority from Japanese application JP2009 251597 filed on Nov 2 2009 the content of which is hereby incorporated by reference into this appli cation BACKGROUND OF THE INVENTION The present invention relates to start up acceleration tech nology used in wireless data communications systems includ ing a wireless video image transmission device and wireless reception device which intermittently perform reception pro cessing within standby periods for making faster the startup procedure of these video transmission and reception devices while simultaneously reducing electrical power consumption in standby events Conventional known power saving type wireless commu nication techniques for causing a cen
8. SON SENSED 02 51 PERSON DETECTION SIGNAL OVER Ch_N d 5103 U S Patent Jun 24 2014 Sheet 1 of 7 05 8 760 512 B2 FIG 1 S103 REPLY FOUND Y REPLY FOUND U S Patent Jun 24 2014 Sheet 2 of 7 FIG 2 V POWER OFF NORMAL STANDBY MODE PERSON DETECTION SIGNAL RECEIVED S202 Y SEND REPLY COMMAND SPECIFIC STANDBY MODE PREDEFINED TIME MEASUREMENT CONTINUATION CODE RECEIVED S206 Y SEND REPLY COMMAND US 8 760 512 2 U S Patent Jun 24 2014 Sheet 3 of 7 05 8 760 512 2 303 MONITOR RECEIVER 1 MONITOR RECEIVER 3 I I I I 304 STARTUP REQUEST i TIME TIME FIG 4B TIME U S Patent Jun 24 2014 Sheet 4 of 7 US 8 760 512 B2 Ti 400 RADIOVIDEO CHECK STARTUP TRANSMITTER STANDBY OPERATION PROCESSING 400 202 500 501 USER OPERATION 506 503 RADIO VIDEO SEA EST STARTUP RECEIVER SIGNAL fit PROCESSING TIME RADIO VIDEO STANDBY STANDBY RADOVDED_ ter 500 USER 5027 RADIO VIDEO STANDBY STANDBY RECEIVER OPERATION ra STARTUP PROCESSING TIME 507 504 U S Patent Jun 24 2014 Sheet 5 of 7 US 8 760 512 B2 PERSON ON DETECTION OUTPUT OFF 604 507 506 207 506 506 RADIO VIDEO KE SEND PERSON TED PERSON STANDBY STA
9. US008760512B2 az United States Patent Patent No US 8 760 512 B2 Ogi et al 45 Date of Patent Jun 24 2014 54 WIRELESS VIDEO TRANSMISSION DEVICE 2009 0195704 1 8 2009 Bombara 348 734 AND WIRELESS VIDEO RECEPTION 2009 0247085 10 2009 Misumi 455 63 3 DEVICE 2010 0118811 Al 5 2010 Lee et al 370 329 2010 0280671 1 11 2010 Lee 700 286 75 Inventors Yuya Ogi Yokohama JP Nobuaki FOREIGN PATENT DOCUMENTS Kabuto Kunitachi JP JP 7 303276 11 1995 73 Assignee Hitachi Consumer Electronics Co JP 8 265823 10 1996 Ltd Tokyo JP JP 2006 050521 2 2006 JP 2007 096462 4 2007 Notice Subject to any disclaimer the term of this IE 2008 104100 5 2008 patent is extended or adjusted under 35 OTHER PUBLICATIONS U S C 154 b by 345 days JP Office Action for Japanese Application No 2009 251597 issued 21 Appl No 12 912 896 on May 21 2013 22 Filed Oct 27 2010 cited by examiner 65 Prior Publication Data Primary Examiner Dave Czekaj US 2011 0102589 A1 May 5 2011 Assistant Examiner Nam Pham 74 Attorney Agent or Firm Antonelli Terry Stout amp 30 Foreign Application Priority Data Kraus LLP Nov 2 2009 JB eerte 2009 251597 57 ABSTRACT A technique is provided for using in a wireless video trans 51 Int CI d HOAN 9 47 2006 01 mission device and a plurality of wireless video reception 52 US C
10. V set is in its standby state In this power off state when the presence ofa person is detected by the human body detector the device may also be designed to go into the specific standby mode stated above By powering off the radio unit prior to detection of the presence of a person in this way it is possible to enhance the power saving effect Traditionally the human detector based TV power saving technique has been used in order to force TV to go into the standby mode while no person is found near or around the TV according to this invention the power saving feature is also usable effectively for setting the radio video receiver device in the standby state when the TV set is in standby also Additionally in the process of the startup request verifica tion to be executed upon detection of the presence ofa person by the human body detector the method for searching all communication channels may be employed Alternatively a technique is employable for searching only the limited num ber of communication channel candidates by the method of the first embodiment stated supra Obviously it is also per missible to search both the limited communication channel candidates and at least one of the other communication chan nels as in the second embodiment INDUSTRIAL APPLICABILITY This invention is adaptable for use in wireless data com munications systems for transmitting over the air a video audio signal s from a radio video transmitter
11. a case where a person is detected on the radio video receiver device side startup request verification of all channels is also performed while prelimiting usable communication channel candidates thereby achieving speed up of activation processing and improvement of stability of startup sequence A time period T6 for the startup request verification in the specific standby mode consists essentially of a first period 802 in which the limited communication channel candidates are assigned and a second period 803 which comes next to this first period 802 and in which at least one of those communication channels otherthan the communication channel candidates is assigned In FIG 8B there is shown a case where the limited commu nication channel candidates are channels ch1 and ch2 as an example In the case of the limited selected communication chan nel candidates being ch1 and ch2 these channels ch1 and ch2 are assigned within the first period 802 in a similar way to the first embodiment stated supra On the other hand one of those communication channels other than the channel candidates is assigned within the second period 803 Supposing that the total communication channel number is 21 for example respective channels ch3 ch19 are sequentially assigned within the second period 803 during verification of 19 startup requests For instance in the example of FIGS 8A 8B a channel ch3 is assigned within the second period 803 in the first startup re
12. and which was wirelessly sent from the radio video receiver device group 301 is received by a trans mission receiver unit via an antenna ofthe radio video trans US 8 760 512 B2 5 mitter device 302 then this control command is subjected to kind type analysis by a CPU within the radio video transmit ter device 302 If the control command is for switching the playback video ofthe HDD recorder 304 as stated previously the CPU sends this command to the HDD recorder 304 via a consumer electronics control CEC line of HDMI cable In this way the wireless network 300 equipping the AV equipment the radio video transmitter device 302 and radio video receiver device group 301 is constituted An explanation will be given below of one example of the processing referred to as the startup sequence hereinafter of from the user s startup request in a standby or wait period up to the actual transition to startup processing Note here that in the explanation below a direction of signal transmission from the radio video transmitter device 302 of FIG 3 to the radio video receiver group 301 is defined as the downward flow whereas the inverse direction thereof is defined as the upward flow More specifically here a video audio signal and acontrol command of from the radio video transmitter device to theradio video receiver group become the downward direc tion a control command of from the radio video receiver device to radio video transmi
13. ation performing period T2 makes it possible to lower the electrical power consumption within standby time period however this results in an increase in length of a time cycle for performing the startup request verification 400 which in turn leads to a decrease in performance of responding to the user s manual operation For example in the time chart of FIG 5A when letting T1 2 s T2 8 s and T5 5 s the startup processing gets started after the elapse of about 10 s in maximum since the user has completed his or her operation This might give some sort of uncomfortable feeling to the user Consequently this embodiment is arranged to limit in advance or prelimit i e lessen usable communication US 8 760 512 B2 7 channel candidates in a case where the presence ofa person is detected on the radio video receiver device side thereby shortening the startup request verification time and thus accelerating or speeding up the activation processing For example as shown in FIG 4B in case the communication channel candidates usable on the radio video receiver device side are channels ch1 ch3 the startup request verification is not performed with respect to all available communication channels but may be performed with respect to such channels only within a time period T3 401 For example in case the wireless system is arranged to have communication channels whose number X is 21 when supposing that the number of usable communica
14. aving the steps of presetting a plurality of communication channel can didates e g channels ch1 to ch3 and using them in the specific standby mode Another method may also be employed which includes the steps of having searched in advance and prestored before the detection of a person by the human body detector 17 those channel candidates 1 cur rently unused or idle channels usable for communication between radio video receiver and transmitter devices and using them in the specific standby mode As has been stated above according to this embodiment in case where the radio video receiver device detects the pres ence ofa person using the human body detector usable com munication channel candidates are reduced or limited in num ber This makes it possible to shorten the time cycle of the intermittently performed startup request verification without having to increase the standby power thereby enabling speed up of the startup sequence In addition even when once limited communication channel candidates become unusable due to a change in radio wave condition or else it is still possible by transition to the normal standby mode in case there is no reply command in response to a continuation command to prevent the occurrence of a mismatch in power supply condition between the radio video receiver device and the radio video transmitter device Although in this embodiment one illustrative example with the human body detec
15. ccordance with the embodiment FIG 3 is a block diagram showing one exemplary configu ration of a wireless network which employs the embodiment of this invention US 8 760 512 B2 3 FIGS 4A and 4B are pictorial diagrams showing a process for verification of a startup request in accordance with an embodiment FIGS 5A 5B are time charts of a startup sequence in accordance with this embodiment FIG 6 is a time chart of a standby mode transition opera tion in accordance with the embodiment FIG 7 is a diagram showing an exemplary configuration of a wireless video reception device in accordance with the embodiment FIGS 8A and 8B are pictorial diagrams showing a process for verification ofa startup request in accordance with another embodiment of the invention FIGS 9A 9B are pictorial diagrams showing a process for verification of a startup request in accordance with a further embodiment of the invention DETAILED DESCRIPTION OF EMBODIMENTS Embodiments in accordance with this invention will be described with reference to the accompanying drawings below Embodiment 1 FIG 3 is a block diagram showing one example of the configuration of a wireless communication system in accor dance with a first embodiment of this invention The illustra tive wireless communication system has a wireless network 300 This wireless network 300 includes a wireless or radio video transmission device 302 and a radio video reception grou
16. ch the radio video receiver device 15 a monitor display video audio signal with which are superimposed a header and control command to be wirelessly transferred from the radio video transmitter device 302 is received through an antenna 15 and transmitter receiver unit 13 This received video audio signal is demodulated by a modulation demodulation or modem unit 12 The video audio signal that was demodulated by the modem unit 12 is supplied to a digital signal processing unit 11 The digital signal processor DSP 11 applies image pro cessing or else to the demodulated video signal and then 20 25 30 35 40 45 50 55 60 65 4 supplies this signal to an image display unit 10 provided in the post stage The image display unit 10 is constituted for example from a liquid crystal display LCD or a plasma display panel or the like for displaying video images based on the signal from the DSP 11 Additionally the header and control command that are superimposed with the video audio signal are also demodulated by the modem unit 12 in a similar way The demodulated header and control command are sup plied to a central processing unit CPU 14 A human body detection unit 17 functions to detect the information concerning the presence of a person or people which is driven and controlled by a drive unit 16 to detect and determine whether a viewing person is present near or around the radio video receiver device 306
17. device to a radio video receiver device Especially in such systems this invention is suitably employable in the case of speeding up the activation operation relative to the startup processing based on the user s manual operations for example It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims The invention claimed is 1 A wireless video reception device configured to receive a video signal sent wirelessly from a wireless video transmis sion device said wireless video reception device comprising ahuman detection unit which detects information concern ing presence of a person 20 25 30 35 40 45 50 55 60 65 14 a transmitter receiver unit which by using one of a prede termined number of communication channels receives the video signal from said wireless video transmission device and performs wireless communication with said wireless video transmission device and a control unit which is coupled to said human detection unit wherein said control unit transmits from said transmitter receiver unitto said wireless video transmission device a person detection signal based on the detected information by using a preset one of said prede
18. ion channel candidates Regarding this selection an explanation will be given later explanation will now be given of the processing to be executed by the CPU of the radio video transmitter device with reference to FIG 2 Incasethe radio video transmitter device is powered off at step S200 control is provided to transit to the normal standby mode at step S201 In the normal standby mode the startup request verification 400 which searches all the com munication channels is performed in the way stated above The radio video transmitter device retains the normal standby mode at step S201 until it receives a person detection signal from the radio video receiver device at S202 Upon receipt ofthe person detection signal at S202 it transmits at S203 the above stated reply command with respect to this person detection signal toward the radio video receiver device After the signal transmission transition is made to the specific standby mode at S204 for performing the startup request verification 401 which searches currently usable communi cation channel candidates only Thereafter the length of a time is measured at S205 which is taken since transmission ofthe reply command Then judgment is made S206 as to whether the above stated continuation command from the radio video receiver device is to be received within a time period of from the transmission of the reply command up to the elapse of a prespecified time When the c
19. ising a storage unit which stores therein information of said any one of the predetermined number of communication channels and another communication chan nel wherein the information of said any one of the predeter mined number of communication channels and another com munication channel being stored in said storage unit is arranged to be sent by said transmitter receiver unit to said wireless video reception device 10 The wireless video transmission device according to claim 8 wherein at least one communication channel other than said limited communication channels is further searched in said second standby mode
20. l devices which intermittently perform signal reception AN cessing within standby periods a human body detection unit uere TEE NM DEC 348 143 348 E7 085 to accelerate the start up of the wireless video transmission 58 Field of Classification Search and reception devices When the presence of a person is USPC m i Vs 348 143 detected by the human body detector a person detection See application file for complete search history signal is sent to a wireless video reception device or the 56 References Cited transmission device to thereby limit usable communication U S PATENT DOCUMENTS channel candidates in number The limited number of usable channel candidates are then used to perform intermittent sig nal reception thereby shortening the searching time cycle of such intermittent reception within a standby period thus less ening the startup time from the standby state between the wireless video transmission and reception devices and also reducing standby power thereof 10 Claims 7 Drawing Sheets 5 799 241 8 1998 Matsubara et al 2005 0281234 Al 12 2005 Kawamura et al 370 338 2006 0171343 Al 8 2006 Maehara et al 2007 0066329 Al 3 2007 Laroia et al 2007 0136772 Al 6 2007 Weaver et al 725 95 2007 0171874 Al 7 2007 Tanaka 370 332 2008 0022324 Al 1 2008 Yangetal 725 81 Y POWER OFF St00 5101 Y PER
21. mitted at step S102 to the radio video transmitter device over a communication channel ch N Then a decision is made at S103 as to whether there is a reply command from the radio video transmitter device with respect to the person detection signal transmitted Here let the default value of N be 1 More specifically the person detection signal is sent via the communication channel ch1 at first In case there is a reply command from the radio video transmitter device tran sition is doneto the specific standby mode at S104 followed by execution of the startup request verification 507 which searches limited communication channel candidates only Alternatively in case there is not any reply command from the radio video transmitter device 1 is added at S109 to the value of the communication channel number N Then judg ment is made at S110 as to whether such value of N is less than or equal to the total communication channel number X e g 21 In case the N value is less than or equal to X the procedure goes to step S102 again if it is larger than X then transit to the normal standby mode After having transited to the specific standby mode the CPU 14 measures at step 5105 a time elapsed after having received the reply command In case a predetermined length of time has been elapsed since the reception of the reply command whether a person is present or absent is again judged at step S106 by the human body detector unit
22. o receiver device Embodiment 4 fourth embodiment ofthis invention differs from the first embodiment in that it does not perform the communication US 8 760 512 B2 13 channel searching intermittent signal reception operation when the radio video receiver device executes startup request verification in the normal standby mode In the fourth embodiment in a case where the presence of a person is not detectable by the human body detector the signal reception processing within the standby period is not performed in addition the power supply of a radio unit e g wireless communication module including the modem unit transmitter receiver unit and others is forced to turn off thereby making it possible to reduce power consumption For example in the startup request verification process shown in FIGS 4A 4B when the presence ofa person is not detectable by the human body detector control is provided to maintain the standby operation of the time period T2 Upon detection of the presence of a person the above noted radio unit is controlled so that the startup request verification ofthe period T1 is performed for first time This control is performed by the CPU 14 of the radio video receiver device and or the CPU of the radio video transmitter device In case the TV receiver set that is the radio video receiver device has its own built in radio unit or offers cooperative functionality the radio unit is powered off when the T
23. on sensitive sensor and an image pickup device 3 The wireless video reception device according to claim 1 wherein said human detection unit detects as the informa tion concerning the presence of a person a remote control signal from a remote controller to be used for operation of said wireless video reception device 4 The wireless video reception device according to claim 1 wherein said human detection unit detects as the informa tion concerning the presence of a person a signal output signal from a signal output device being wire connected to said wireless video reception device 5 The wireless video reception device according to claim 1 wherein when the presence of a person is detected by said human detection unit in said first standby mode said control unit transmits from said transmitter receiver unit said person detection signal representing the detection ofthe presence of a person to said wireless video transmission device by sequentially switching said predetermined number of com munication channels and shifts to said second standby mode when said transmitter receiver unit receives a reply command with respect to said person detection signal from said wire less video transmission device 6 The wireless video reception device according to claim 5 wherein said selected communication channels are com munication channels used for transmitting said person detec US 8 760 512 B2 15 tion signal to said wireless
24. on 503 periodically in a similar manner to the radio video transmitter device 302 A time cycle ofthe startup request verification 400 and a time period of the standby operation 503 at the radio video receiver device 306 in the specific standby mode may be the same as a time cycle T3 T4 of the startup request verification 400 and a period T3 of standby operation 500 at the radio video transmitter device 302 in the specific standby mode or alternatively may be different therefrom Atacertaintime point when the user sends as indicated by numeral 502 in FIG 5B to the radio video receiver device 306 an RC signal which contains a control command for activation ofthe video receiver device 306 this video receiver device 306 uses a specific channel which is the candidate prelimited usable communication channel e g channel ch1 to transmit 504 a startup request signal for use as the control command toward the radio video transmitter device 302 In case the radio video transmitter device performs startup request verification 401 and searched the communication channel ch1 during transmission ofthe startup request signal this channel ch1 15 used to receive the startup request signal that is the control command for activation as sent from the radio video receiver device Then the radio video transmitter and receiver devices perform the startup processing opera tions 501 and 506 respectively As stated above in the specific standby mode in acc
25. ontinuation command is received the above stated reply command is sent S207 to the radio video receiver device In case it is unable to receive the continuation command until a given length of time elapses transition is made to the normal standby mode at S201 Note here that it is also permissible to multiplex the information of a time taken up to the time out of the specific standby mode into the reply command or alternatively mul tiplex the information of a continuation command transmis sion time cycle in the person detection signal To do this it is desirable to set the prespecified time used in the step S205 so that this is longer than the predetermined time of the radio video receiver device at step S105 shown in FIG 1 One example of the processing for selecting usable com munication channel candidates in the specific standby mode will next be described with reference to FIGS 1 and 6 Inthe normal standby mode when an output of the human body detector 17 of the radio video receiver device changed from the OFF state 1 no person detection state to ON state person detected state the radio video receiver device transmits at step S102 of FIG 1 the person detection signal by using a communication channel ch N at first N 1 as indicated by numeral 603 in FIG 6 The radio video trans mitter device receives 601 the person detection signal from the radio video receiver device in the process of performing the startup re
26. or dance with this embodiment the time cycle for performing the startup request verification 401 in the startup sequence is short so the performance of responding to the user s manual operations improves accordingly jai 5 20 25 30 35 40 45 50 55 60 65 8 An explanation will next be given using a flowchart of FIG 1 ofthe processing to be executed by the CPU 14 ofthe radio video reception device for transition between the nor mal standby mode and the specific standby mode using the human body detector unit 17 in this embodiment In a case where the radio video receiver device is powered off at step S100 the human body detector 17 detects the information concerning the presence of a person for determi nation of whether a person is present near the radio video receiver device at step S101 In case any person is absent transition is made to the normal standby mode at S108 In this normal standby mode the startup request verification which searches all communication channels is performed in the way stated supra Note here that the judgment of whether a person is present or absent by means of the human body detector 17 at S101 may be performed on an all time basis or alternatively may be synchronized with the intermittently performed startup request verification 507 On the other hand in case it is judged by the human body detector 17 that a person is present a person detection signal is trans
27. p 301 which includes a plurality of radio video receiver devices 306 to 309 examples of which are a monitor such as television TV receiver set or else an amplifier for audio output and so forth This wireless network 300 is arranged to internally perform the following operations wirelessly send ing video and audio signals from the radio video transmitter device 302 to the radio video receiver device group 301 and communicating a control command between the radio video transmitter device 302 and radio video receiver device group 301 To the radio video transmitter device 302 equipment for output of video and audio signals is wire connected by a signal transmission cable Examples of the equipment include but not limited to a digital versatile disk DVD player 303 and hard disk drive HDD recorder 304 An example of the signal cable is a high definition multimedia interface HDMI cable It is noted that in some cases the DVD player 303 HDD recorder 304 monitor and amplifier or else will be called the AV equipment hereinafter Also note that the radio video transmitter device 302 may be a set top box STB having a tuner for receiving TV broadcast programs An operation of the above stated system will be explained by also using FIG 7 below FIG 7 shows an exemplary configuration of one of the radio video receiver devices 306 309 in accordance with this embodiment which is applied to this system here it shows an example in whi
28. power supply of AV equipment be kept operative SUMMARY OF INVENTION The above stated prior art techniques are faced with prob lems which follow In JP A 7 303276 use of the central control device is required also required is electrical power for activating and rendering operative the central control device per se Although it is possible to reduce total power consump tion by applying the technique as taught therefrom to large scale wireless communications of cellular phone base sta tions or the like there is a risk that it becomes unable to reduce total power consumption in small size networks such as a home use one As for JP A 2007 96462 this fails to disclose therein any teachings about the consumed power reduction using a human sensitive sensor in the case of performing wireless communications This invention has been made in view of the above stated problems and an object of the invention is to provide a jak 5 20 40 45 50 60 65 2 technique capable of speeding up the startup of a device s and reducing electrical power consumption in standby events in the case of performing intermittently the within standby period signal reception processing between a wireless video transmission device and a wireless video reception device This invention provides a wireless video reception device which receives a video signal that is wirelessly sent from a wireless video transmission device The wireless video recep
29. quest verification 400 intermittently and regards a communication channel ch1 as the channel usable for com munication and then stores the information of this commu nication channel candidate in any one of a semiconductor memory not depicted and an internal storage region of the CPU ofthe radio video transmitter device these will collec tively be called the storage unit hereinafter Then at step 5103 of FIG 1 the radio video receiver device determines whether there is a reply command from the radio video trans mitter device In the example of FIG 6 the radio video receiver device receives no such reply command from the radio video transmitter device so that 1 is added to the value 20 25 30 35 40 45 50 55 60 65 10 of N to thereby switch the communication channel to a chan nel ch2 at step S109 of FIG 1 Here the total communication channel number X is 21 The N s value i e 2 is less than or equal to X Thus the procedure returns to step S102 for sending the person detection signal again as shown by 604 in FIG 6 In a similar way to the case of channel ch1 the radio video transmitter device receives 605 the person detection signal from the radio video receiver device in the process of intermittently performing the startup request veri fication 400 and decides a communication channel ch2 to be the usable communication channel candidate and then stores the information ofthi
30. quest verification period channel ch4 is assigned within the second period 803 in the next startup request verification period and ch5 is assigned within the second period 803 in the further next startup request verifi cation period By arranging the startup request verification time period in this way it becomes possible to set longer the time cycle for startup request verification with respect to all communication channels while simultaneously shortening the time taken for startup request verification of the limited communication channel candidates Accordingly even when the limited com munication channel candidates e g ch1 ch2 become unus able due to a change in radio wave condition or the like it is still possible to use other communication channels e g ch3 ch4 etc thereby improving the stability of the startup pro cessing of the whole wireless transmission reception system For example suppose that the limited communication chan 20 25 30 35 40 45 50 55 60 65 12 nel candidate number is 2 Assume that the number of com munication channels to be assigned within the second period 803 is 1 In this case the startup request verification 801 is performed in such a way as to search communication chan nels in the following order 1 2 3 Standby 7 1 2 4 Standby T7 1 2 5 Desirably the above stated cycle of the startup request veri fication with respect to all communication
31. radio video transmitter device and radio video receiver device In the third embodiment in the radio video transmitter and receiver devices which intermittently perform signal recep tion processing within their standby periods when detecting the presence ofa person by the human body detector the time cycle of the startup request verification 400 is set shorter than that in the normal standby mode With this arrangement it is possible to improve the response performance to the user s operations and speed up the activation of the radio video transmitter and receiver devices although electrical power consumed during standby increases when compared to the normal standby mode As a matter of course the specific standby mode may be arranged to search only selected communication channel can didates as in the first embodiment rather than searching all available channels for the startup request verification purpose while shortening the startup request verification cycle as in the third embodiment Another employable arrangement is that while shortening the startup request verification cycle in the specific standby mode as in the third embodiment the startup request verification is modified to search the selected communication channel candidates and other communica tion channels as in the second embodiment Arranging in this way makes it possible to suppress an increase in power con sumption while simultaneously speeding up the startup ofthe vide
32. request verification 400 and the standby operation within its standby period This will be called the normal standby mode first standby mode hereinafter Next one example of the startup sequence in the case of a control command being sent from the radio video receiver device 306 will be described with reference to FIG 5A The radio video receiver device 306 also periodically repeats execution of the startup request verification 400 and a standby operation 503 within its standby time period in a similar way to the radio video transmitter device 302 A time cycle of the startup request verification 400 and a time period of the standby operation 503 in this radio video receiver device 306 may be the same as a cycle T1 T2 of the startup request verification 400 and the period T1 of standby opera tion 500 in the radio video transmitter device 302 or may be different therefrom At a given time point when the user sends as indicated by 502 in FIG 5A an RC signal which contains a control com mand for activation of the radio video receiver device 306 to the radio video receiver device 306 the radio video receiver device 306 first uses a communication channel ch1 to transmit a startup request signal 504 indicative of a control command toward the radio video transmitter device within a time period T5 In case no response is obtained from the radio video transmitter device within the period T5 the radio video receiver device 306 switches
33. s channel ch2 in the storage unit At this time ch1 and ch2 are to be stored in the storage unit as the information of currently usable communication channels In case the number of such usable communication channel can didates being saved in the storage unit reaches a prespecified number in FIG 6 the case of two channel candidates is shown as an example the radio video transmitter device transmits 602 its reply command to the radio video receiver device The radio video transmitter device which has sent the reply command and the radio video receiver device that has received this reply command go into the specific standby mode Hence in this example the radio video transmitter device is expected to search two communication channels consisting ofthe channels ch1 and ch2 in the event of startup request verification in the specific standby mode In this way those communication channel candidates which are to be searched in the specific standby mode are selected In the specific standby mode to which transition is made when the presence of a person is detected a reduced or limited number of communication channels are subjected to the search which number is less than the number of those channels to be searched in the normal standby mode i e the total channel number The selection of communication channel candidates should not exclusively be limited to the above noted example and may be replaced for example by a method h
34. tection signal based on presence of a person and trans mitted from said wireless video reception device by using a preset one of said predetermined number of communication channels wherein said control unit is configured to perform transition from the first standby mode to the second standby mode when 5 16 said transmitter receiver unit receives said person detec tion signal based on presence of a person and wherein said selected communication channels to be searched in the second standby mode includes the communication channel via which said person detection signal based on presence of a person is transmitted 8 The wireless video transmission device according to claim 7 wherein said transmitter receiver unit receives said person detection signal concerning the presence of a person which was sent from said wireless video reception device over the preset one of said predetermined number of commu nication channels and is capable of sending a reply command in response to receipt of said person detection signal to said wireless video reception device via any one of the predeter mined number of communication channels and another com munication channel and wherein said any one of the predetermined number of communica tion channels and another communication channel are used as limited communication channels to be searched in said second standby mode 9 The wireless video transmission device according to claim 8 further compr
35. termined number of communication channels when the presence of the per son is detected by said human detection unit while oper ating in a first standby mode of said wireless video reception device wherein in the first standby mode said wireless video reception device intermittently searches all said predetermined number of communications chan nels to be used for wireless communication and when said transmitter receiver unit receives a reply command in response to said person detection signal from said wireless video transmission device said wire less video reception device transitions to a second standby mode which intermittently searches selected communication channels selected from and fewer in number than said predetermined number of said com munication channels where the selected communica tion channels are selected based on a predetermined selection scheme said control unit when a control command for starting said wireless video transmission device or said wireless video reception device is received in said second standby mode sends from said transmitter receiver unit a startup request signal based on said control command by using one of said selected communication channels and wherein said selected communication channels include the communication channel via which said person detec tion signal is transmitted 2 The wireless video reception device according to claim 1 wherein said human detection unit is one of a pers
36. the channel ch1 to a communi cation channel ch2 next thereto and then transmits a startup request signal 505 In case the radio video transmitter device 302 performs the startup request verification 400 and searches the communication channel ch2 during transmission ofthe startup request signal this startup request signal that is the control command for activation from the radio video receiver device is received using the communication channel ch2 then the radio video transmitter device and radio video receiver device perform the startup processing operations 501 and 506 respectively In this way the transmission of a star tup request signal and the search for a usable communication channel by verification of a corresponding response there from are sequentially performed with respect to those chan nels of from ch1 up to ch21 under an assumption that the total channel number X is 21 Hence in case the channels ch1 ch20 are unusable because these have already been assigned for communication with other devices for example the above stated transmission of startup request signal and the verification of its corresponding response have to be done with respect to each of the channels ch1 ch20 thereby caus ing a time taken for searching the communication channel to increase in length resulting in a decrease in response perfor mance In the case of the above stated one example of the startup sequence making longer and longer the standby oper
37. tion channel candidates is 3 it becomes possible to perform the startup request verification within a time cycle that is shortened to one seventh 17 while letting power consumption be kept almost the same as that in the case of searching all available communication channels In other Words a specific arrangement is employed for prelimiting the usable communication channel candidates in the case of a person being detected by the radio video receiver device that is reducing the communication channels that are searched in the case of the person detection so that these are less in number than those in the case of no person being sensed to thereby shorten the time cycle of the startup request verification This mode of performing the startup request verification relating to these limited communication channels will be called the specific standby mode second standby mode in the description below With this arrange ment it becomes possible to speed up the startup sequence of the radio video transmitter device and radio video receiver device while at the same time maintaining electric power consumption at substantially the same level as that in the case of searching all communication channels Next a startup sequence in the specific standby mode of this embodiment will be described with reference to FIG 5B In the specific standby mode the radio video receiver device 306 also repeats startup request verification 507 and standby operati
38. to indirectly detect the presence or absence of a viewing person by detec tion of the fact that either a wire connected signal source or a built in signal source not shown other than wireless input of the radio video receiver device is currently selected as an external input in a state that the power supply of radio video receiver device is turned on Other examples include an arrangement for indirectly detecting the presence or absence of a viewer by detection of receipt of a certain kind of signal by the RC light receiver unit 18 and or by detecting using an illuminance sensor the fact that indoor brightness exceeds a given threshold value In FIG 3 case where the user is watching and listening to a certain video reproduced from the HDD recorder 304 by the monitor receiver device 1 that is the radio video receiver device 306 when he or she wants to switch the presently reproduced video to another playback video that is recorded in the HDD recorder 304 the user manually oper ates the remote controller for use with the HDD recorder 304 to thereby send to the receiver device 1 a remote control RC signal containing therein a control command for the playback video change The receiver device 1 optically receives this RC signal and then wirelessly transmits the control command signal to the radio video transmitter device 302 by way of the above stated modem unit 12 transmitter receiver unit 13 and antenna 15 The control comm
39. tor 17 being attached to the radio video receiver device was shown this detector may be attached to the radio video transmitter device It would readily occur to those skilled in the art that this embodiment is also applicable US 8 760 512 B2 11 in a similar way even in cases where the radio video receiver and transmitter devices are interchanged in function with each other Embodiment 2 second embodiment of this invention will be explained using FIGS 8A and 8B below The second embodiment is different from the first embodiment in selection of commu nication channels to be searched in the process of verifying a startup request in the specific standby mode in the radio video transmitter device and radio video receiver device FIG 8B shows one example of the process of such startup request verification in the case of the second embodiment being applied FIG 8A is the same as FIG 4A As previously stated in the radio video transmitter device and radio video receiver device which intermittently perform signal reception processing within their standby time periods it becomes possible by limiting the channel candidates usable for communication between the radio video transmit ter and receiver devices by use of the human body detector to shorten the time as taken for activation from the standby state ofeach ofthe radio video transmitter and receiver devices and also reduce the standby power thereof In the second embodiment in
40. tral control apparatus to manage interconnection between radio terminals include a standby control method which is recited in JP A 7 303276 for example In this Japanese patent literature there is dis closed a technique adapted for use with a wireless communi cation control scheme having a couple of radio terminal devices which intermittently perform signal reception pro cessing within standby periods When a calling time point of transmission side radio terminal is not identical to the signal reception time of a reception side radio terminal a control device which manages wireless communication between these radio terminals notifies the transmission side radio ter minal of the nearest signal reception time of the reception side radio terminal After the transmission side radio terminal that has received such notice notified a calling connection time to the control device transition is made to a standby state to thereby achieve steady connectivity and reduction of total electric power consumption Additionally audio video AV equipment power saving techniques using a human sensitive sensor include the one that 15 disclosed for example in JP A 2007 96462 Dis closed in this patent literature is a technique for reducing power consumption of AV equipment by turning off the AV equipment s power supply when a predetermined length of time is elapsed after a user acted to go away from a nearby location of the AV equipment while letting the
41. tter device becomes the upward direction Also note that the explanation below takes as an example a startup sequence which begins from a specific radio video receiver device 306 for purposes of brevity of explanation When the user wants to activate the radio video receiver device 306 within a standby time period in which s he is watching no videos the user manually operates a remote controller for the radio video receiver device use for example an operation of turning on a power button of the remote controller to thereby transmit an RC signal that con tains a control command for activation e g power on com mand toward the radio video receiver device 306 The radio video receiver device 306 receives the light of this RC signal and wirelessly transfers this control command signal to the radio video transmitter device 302 The control command that was wirelessly sent from the radio video receiver device 306 is received by the transmis sion receiver unit via the antenna not shown of the radio video transmitter device 302 This control command received 15 passed to the CPU within the radio video transmitter device 302 and subjected to kind analysis thereby If the control command is for startup as stated supra the CPU of the radio video transmitter device 302 performs startup processing such as electrical power feed to respective parts of the radio video transmitter device 302 software program launching and others In this wireless
42. video transmission device from among said predetermined number of communication chan nels 7 A wireless video transmission device configured to wire lessly send a video signal to a wireless video reception device said wireless video transmission device comprising atransmitter receiver unit which transmits the video signal to said wireless video reception device by using one ofa predetermined number of communication channels which are used for wireless communication with said wireless video reception device and receives a startup request signal transmitted from said wireless video reception device by using one of said predetermined number of communication channels and acontrol unit which controls in order to receive the startup request signal transmitted from said wireless video reception device by said transmitter receiver unit tran sition between a first standby mode in which said wire less video transmission device intermittently searches all of said predetermined number of communication channels and a second standby mode in which said wireless video transmission device intermittently searches selected communication channels selected from and fewer in number than said predetermined num ber of said communication channels where the selected communication channels are selected per a predeter mined selection scheme said transmitter receiver unit is configured to receive while operating in said first standby mode a person de
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