GB2146821A - Display apparatus - Google Patents

Abstract

A video display 1 for advertising in a shop has an ultrasonic transmitter 2 which broadcasts continuously a signal of 27K Hz throughout the customer area 3 of the shop. Adjacent to transmitter 2 there is located an ultrasonic receiver 4 directed towards area 3 thereby to receive any ultrasonic waves reflected off objects in the area. Any moving object generates a change in the ultrasonic waves reaching receiver 4; when a comparator monitor 6 notes such a change, a video tape recorder 10 is activated in order to play back, on television receiver 5, a video tape of an advertisement. <IMAGE>

Description

SPECIFICATION Display apparatus The present invention relates to display apparatus incorporating a television receiver.

In the invention, the presence of a moving person or object is used to operate the video tape recorder or disc player in a predetermined manner.

Thus, the present invention provides display apparatus comprising means to produce a video recording, the video reproducing means being electrically connected to a television receiver, means to detect the presence of a person or object moving in a predetermined region and means to activate, when the detector means indicates such presence, operation of the reproducing means.

In one form of the invention, the activation means operates, in use, the video reproducing means such as to play back a pre-recorded tape or disc for display on the television receiver which is positioned such that it can be readily seen from the predetermined region. Thus this form of the display apparatus is suited to situations (for example in a shop or at an exhibition) in which it is desirable to attract the attention of a person whose presence is detected by the detection means.

In any form of the invention, the display apparatus may include means to terminate the operation of the video reproducing means in accordance with the detector means indicating the absence of movement in the predetermined zone; the termination means may act on the video reproducing means as soon as no movement is detected, or it may act only after a given time has elapsed since movement was last detected. In another form of the invention, the display apparatus includes means to terminate operation of the video reproducing means after a given time period has elapsed since the initial detection of movement in the region; in this case, operation of the video reproducing means is stopped regardless of whether there is still movement in the region.

Any form of the termination means described above may also initiate a further operation of the video reproducing means, for example the resetting of the video reproducing means to a mode in which it is ready for activation if further movement is detected.

In any form of the invention, preferably the activation means operates the video reproducing means only if the detector means has detected movement for a given time period continuously within the region.

Preferably the detector means comprises an ultrasonic transmitter which, in use, sends out continuously a given signal to the region, and an ultrasonic receiver which detects any change to the received signal caused by movement of persons or of objects within that region.

The video reproducing means may be any suitable form of video tape recorded or video disc recorder, and the television receiver may be a television monitor and may incorporate any suitable form of display, e.g. cathode ray tube or solid state display.

In order that the invention may more readily be understood, a description is now given by way of example, only, reference being made to the accompanying drawings, in which: Figure 1 is a block diagram of display apparatus embodying the present invention; Figure 2 is a block diagram of display apparatus generally similar to that shown in Fig. 1; Figure 3 is a circuit diagram of control equipment for the display apparatus of Fig. 2; Figure 4 is a diagram of the timing waveforms for the equipment of Fig. 2; and Figure 5 is a block diagram of another form of display apparatus.

The block diagram of Fig. 1 shows the elements in a video display 1 for use in a shop. The video display equipment 1 has an ultrasonic transmitter 2 which broadcasts continuously a signal of 27 kHz throughout the customer area 3 of the shop. Adjacent to transmitter 2, there is located an ultrasonic receiver 4 directed towards area 3 thereby to receive ultrasonic waves which bounce off any objects in the area. A television receiver 5 is positioned for easy viewing from customer area 3. At this stage no image is being displayed on television receiver 5; the only elements of the equipment 1 in active operation are transmitter 2 and receiver 3, the remainder being in a "standby" mode.

When movement occurs in customer area 2, the ultrasonic signal received at receiver 3 changes in amplitude or in frequency or in both; a comparitor monitor 6 notes this change and generates an appropriate signal S which is subsequently amplified by amplifier 7 and then passed on to a timer 8. If the signal S exceeds two seconds in duration, a pulse signal P is passed on to "play-mode" operator 9 which activates a video tape recorder 10 to play back a pre-recorded video tape of an advertisment on the television receiver 5.

Thus, within three seconds of a person entering the customer area 2, the television receiver is displaying the start of an advertisment for him or her to watch.

The signal sent out from "play-mode" operator 9 is also passed firstly to a receiverdisabling unit 11 which turns off the ultrasonic receiver 4 and secondly to a timer 1 2 which is set to count over a period corresponding to the time interval for playing back the advertisment. Thus, once this time interval has elapsed, timer 1 2 enables a "stop-mode" operator 1 3 which sends a control pulse to video tape recorder 10 to terminate playback of the video tape. This control pulse also enables a "rewind" operator 14 which sends another control pulse to make the recorder 10 rewind to the start of the advertisement on the video tape; this control pulse from "rewind" operator 14 also enables ultrasonic receiver 4, so that the equipment 1 is now ready once more for activation by a customer.

Figs. 2 to 4 show details of the control and processing circuits for use in video display equipment generally similar to that described above with reference to Fig. 1. In a detector unit 19, an integrated-circuit device 20 forms a variable oscillator, tuned at around 24 kHz by a variable resistor 21, for driving a transmitter transducer 22; an ultrasonic receiving transducer 23 is suitably positioned to detect ultrasonic waves, from transducer 22, which have been reflected back by objects within the customer area, the resultant electrical signal at transducer 23 being suitably amplified by transistors 24 and 25.

Any objects moving within the customer area produce a frequency shift in the ultrasonic waves reflected back to transducer 23, while the stationary objects within the area reflect back waves of frequency 24KHz. Thus when an object moves within the customer area the transducer 23 will receive two different frequencies, which will combine to produce a beat note, this being detected by diode 26. A network formed of capacitor 27 and resistor 28 is used to remove the 24KHz component of the existing signal. The values of resistor 29 and capacitor 30 determine the bandwidth of Doppler frequencies over which the equipment can operate.

Upon output from transistor 31, the remaining signal passes to rectifier capacitor 32 and to charging capacitor 33 so as to convert it to a steady voltage before feeding to the diode pump network formed by diodes 34 and 35.

When the voltage across capacitor 33 reaches 2.6 volts, transistor 37 is turned on resulting in the light-emitted diode 38 being illuminated. The LED 38, which flickers every time there is a beat note, is used during the setting-up of the equipment and also whenever there needs to be testing of the sensitivity of the equipment.

The turning-on of transistor 37 also causes transistor 39 to be turned on; capacitor 40 provides a two second delay before the voltage on Schmitt trigger 41 reaches a threshold level, thereby resulting in the generation of a pulse by monostable 43 which activates a video recorder to the "play" mode by energising relay RL1. The output of monostable 43 is also applied to the data input of the D-type flip-flop 47 whichis clocked by the delayed output of 43 via monostables 44 and 45 and gate 46. The output from flip-flop 47 controls an electronic switch 48 which disables detector 1 9 by switching off its ISV supply.

The output from Schmitt 41, delayed by monostable 50, energises relay RL2 to stop the tape player after a predetermined time, and after a further delay due to monostable 51, relay RL3 is energised to cause the tape to be rewound. The output from monostable 51 is further delayed by monostables 52 and 53 and applied to the clock input of flip-flop 45 via gate 46. Since the output of monostable 43 and hence the flip-flop is now low. the flip-flop changes state and the electronic switch 48 re-energises the detector. The times at which the switching operation take place are evident from the timing waveforms shown in Fig. 4.

The block diagram of Fig. 5 shows the elements of a video display security system 60. Many features of this system correspond to those included in the video display 1 and, where this occurs, the same numerals have been used as for Fig. 1.

The distinction of system 60 over the display equipment 1 is that the ultrasonic transmitter 2 and receiver 3 are now monitoring movement in a predetermined zone 61, rather than merely initiating a pre-recorded display when motion is detected. Any change in the ultrasonic signals received is again processed in monitor 6, amplifier 7 and delay 8, but now the pulse signal P is passed onto a "rncord-mode" operator 62 which acts on video recorder 10 to switch on a video camera 63 directed at zone 61 in order to record what is causing the movement. Operator 62 also instructs video tape recorder 10 to simultaneously turn on television receiver 6 which is located in the guard-room remote from the zone 61, so that there is a real-time display of what is being recorded on video tape recorder 10.

Monitor system 60 has no receiver disabler, so that as long as receiver 4 indicates that there is a change in the ultrasonic signal received and timer 8 produces pulses P, operator 62 will maintain video tape recorder 10 in the record mode; preferably, operator 62 continues to do so for a specified time, e.g. 5 seconds, after the pulses P stop and only thereafter allowing recording to stop. As soon as "stop-mode" operator 64 notes that there is no output signal from operator 62, it instructs the video recorder 10 to stop recording and to return to its stand-by mode, ready to start recording again if further movement in zone 61 is detected. Clearly, no automatic rewinding of the tape cassette in recorder 10 is needed.

The system described with reference to Fig.

5 may be used for any one of a number of applications. For example such a system may be used in hospitals to monitor the movement of seriously ill people (for example during the night) or it may be used in elderly people's homes. Also such a system may be used to monitor animals which are sick or which are in a transient state (for example farmers could use the system to determine when their cows are "on heat").

In one monitor system, a video tape recorder and associated video camera are controlled to turn on automatically at predetermined intervals and remain on for a specified time. The system may be used such that, when so activated, a video recording is made of the area and/or such that the image from the video camera is displayed at a remote monitoring station (e.g. the guardhouse). In one form, the system is activated solely according to this dependent operation. In another form, the time-dependent operation is added to the monitor system described with reference to Fig. 5; thus a recoding is made regularly even if no movement is detected in the zone being monitored.

Claims (5)

1. Display apparatus comprising means to reproduce a video recording, the video reproducing means being electrically connected to a television receiver, means to detect the presence of a person or object when moving in a predetermined region and means to activate, when the detector means indicates such presence, operation of the video reproducing means.

2. Display apparatus according to Claim 1, wherein the activation means operates, in use, the video reproducing means such as to play back a pre-recorded tape or disc for display on the television receiver which is positioned such that it can be readily seen from the predetermined region.

3. Display apparatus according to Claim 1 or Claim 2, wherein the detector means comprises an ultrasonic transmitter which, in use, sends out continuously a given signal to the region, and an ultrasonic receiver which detects any change to the received signal caused by movement of persons or of objects within that region.

4. Display apparatus according to Claim 3, wherein the detector means comprises means to identify a Doppler-shift in the received signal.

5. Display apparatus substantially as hereinbefore described with reference to and as illustrated in Fig. 1 or in Figs. 2, 3 and 4 of the accompanying drawings.