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WO1997020293A1 - Procede et dispositif servant a generer un enregistrement visuel - Google Patents

Procede et dispositif servant a generer un enregistrement visuel Download PDF

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Publication number
WO1997020293A1
WO1997020293A1 PCT/GB1996/002955 GB9602955W WO9720293A1 WO 1997020293 A1 WO1997020293 A1 WO 1997020293A1 GB 9602955 W GB9602955 W GB 9602955W WO 9720293 A1 WO9720293 A1 WO 9720293A1
Authority
WO
WIPO (PCT)
Prior art keywords
picture
assessed
signals
difference
data signals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1996/002955
Other languages
English (en)
Inventor
David Antony Crellin
John Robert Crellin
Robert John Dickinson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to DE69608123T priority Critical patent/DE69608123D1/de
Priority to EP96940029A priority patent/EP0864140B1/fr
Publication of WO1997020293A1 publication Critical patent/WO1997020293A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
    • G08B13/189—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems
    • G08B13/194—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems
    • G08B13/196—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems using television cameras
    • G08B13/19602—Image analysis to detect motion of the intruder, e.g. by frame subtraction
    • G08B13/1961—Movement detection not involving frame subtraction, e.g. motion detection on the basis of luminance changes in the image
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
    • G08B13/189—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems
    • G08B13/194—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems
    • G08B13/196—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems using television cameras
    • G08B13/19665—Details related to the storage of video surveillance data
    • G08B13/19669—Event triggers storage or change of storage policy

Definitions

  • This invention relates to a method and apparatus for generating a visual record that extends over a period of time. It is well known to generate a visual record that extends over a relatively long period of time by record ⁇ ing each frame of the record at a fixed time interval using a video camera. The recorded frames can be played back at a faster rate than they were recorded, enabling a viewer to see in a few seconds an event that may have taken place over a number of hours. At the same time as the picture frames are recorded values from one or more sensors may also be recorded. Such a method may be referred to as data-logging. Such data-logging is satisfactory for events which are continuous at a substantially constant, but slow, rate of change throughout the period of data-logging.
  • an event may involve several periods during which there is a rapid rate of change separated by other periods when there is very little or no change.
  • significant data relating to a period of rapid change may be lost because the rate of recording is slowed down; at the same time much of the available data recording space is used up by insignificant data from recording during a period when there was little or no change;
  • another disadvantage in such a case may be that the amount of insignificant data is much greater than the amount of significant data so that the processing and analysis of the significant data is hampered. It is an object of the invention to provide an improved method and apparatus for generating a visual record that extends over a period of time.
  • a method of generating a visual record that extends over a period of time in which one or more types of data signals, including picture signals, are transmitted to a control unit and a record of only some of the picture signals is maintained, the method including the step of assessing the degree of difference of at least one type of the transmitted data signals from data signals of the same type that have previously been recorded, and maintaining a record of the picture signals corresponding to the assessed data signals in the event that the degree of difference assessed is greater than a preselected threshold amount whilst avoiding the maintenance of a record of the picture signals corresponding to the assessed data signals in the event that the degree of difference assessed is not greater than the preselected threshold amount.
  • the degree of difference of picture signals from picture signals that have previously been recorded is assessed. For most applications, it will be changes in the scene being viewed that it is important to capture and it will therefore be preferred to make a further recording whenever there is a significant change in the scene.
  • the degree of difference of a later scene from an earlier scene may be assessed and it is possible to choose just one of those ways or a plurality of them when assessing the degree of difference.
  • the picture signals are colour picture signals
  • the degree of difference in the aggregate area taken up by a given colour in the picture may be assessed in order to assess the degree of difference between the picture signals.
  • the picture signal will provide an indication of the colour to be allotted to each pixel that may make up the picture; the number of colours that are available is not a factor critical to the present invention but as an example there may be 256 colours.
  • the assessment of the aggregate area taken up by the given colour may be carried out for a plurality of different colours, preferably for substantially all the colours that are recorded; advantageously the colours are divided into groups and the assessment is carried out for one or more different groups of colours.
  • the degree of difference in the brightness of the picture may be assessed in order to assess the degree of difference between the picture signals.
  • the degree of difference in the overall brightness of the picture may be assessed but it is also possible, as well or instead, to assess the degree of difference in a preselected region of the picture.
  • the only type of data signal transmitted to the control unit to be a picture signal
  • the types of data signals transmitted to the control unit include picture signals and one or more other types of data signals and that a record of said one or more other types of data signals is maintained. For most applications the recorded data will be of much greater value if it includes not only a visual record but also a record of data from one or more other sensing devices.
  • the other types of data signals may include signals relating to one or more of the following: air pressure, conductivity, electric current, distance, force, relative humidity, infra red, visible light, magnetic flux, oxygen, pH, position, potential difference, heart pulse rate, radioactive count rate, pressure, sound, speed, temperature, temperature difference and ultra violet.
  • the assessed data signals may be the picture signals, and they may be the only data signals assessed to determine whether or not a record of the transmitted data signals is maintained (although of course, if a record is maintained it would in this case include other types of data signals, apart from picture signals).
  • the assessed data signals are one or more of said other types of data signals and that the picture signals corresponding to the assessed data signals are the picture signals relating to substantially the same moment in time as the assessed data signals; in that case even though the picture signal may not have changed at all, a new recording of the picture signal is maintained because of a significant difference in one or more of said other types of data signals.
  • the requirement may be that a certain time has elapsed since a record of the assessed data signals has been maintained. For example, in the case where a visual record is being made of a scene outside and data signals from a light sensor are being assessed it may be desirable to prevent a new picture record being maintained because of a slow change in brightness. By updating at regular intervals the record of the bright ⁇ ness signal to be u ⁇ ed in the assessment, that can be achieved.
  • the method further includes the step of recording the time to which a maintained record of a picture signal relates. That is of special advantage in the present invention because the spacing in time between successive maintained recordings of the picture signal is likely to be very variable.
  • the preselected threshold amount against which the degree of difference in the assessed data signals is compared is preferably an amount that can be selected by a user of the system. It will be appreciated that in different circumstances a different amount of difference in the assessed data signals will be a significant difference and justify the maintenance of a new record. As already indicated, more than one type of data signal may be assessed and more than one parameter of the data may be assessed for a difference. Each difference examined may have its own associated threshold which, regardless of the amount of any other differences, will cause a new record of the picture signals to be main ⁇ tained, and/or a threshold may be set for a combination of two or more differences.
  • a new record may be maintained in the event of a change in either brightness or sound above a relatively large threshold amount or in the event of a change in both brightness and sound, each above relatively smaller threshold amounts.
  • the assessment of the degree of difference of at least one type of the transmitted data signals from data signals of the same type that have been previously recorded is carried out using those previously recorded data signals that relate to the most recent previous recording. For most applications comparing incoming signals with the ones most recently recorded will be the most advantageous method but it is possible to compare the incoming signals with ones recorded earlier or with a group of previous recordings.
  • the method may include the step of temporarily storing the picture signals and avoiding the maintenance of the temporarily stored picture signals corresponding to the assessed data signals in the event that the degree of difference assessed is not greater than the preselected threshold amoun .
  • the record of the picture signals may be played back in various ways.
  • the rate of playing back successive pictures will vary considerably during the playback but the audience will be given a sense of the time occupied by the various events viewed.
  • Other possibilities are simply to display each recording separately as a still picture, and to play back the pictures with the same time intervals between them regardless of the time intervals between the recording of them.
  • the picture signals during playback it is preferable to display one or more other types of data signals that may have been recorded.
  • the time of the recording is preferably displayed if that has been recorded.
  • the best way of displaying other types of data will vary according to the nature of the data. For example, temperature data may be displayed digitally and/or shown graphically, although if desired it could be shown by the colour in which the pictures were presented.
  • the present invention also provides an apparatus for generating a visual record that extends over a period of time, the apparatus including a control unit which includes a memory, and one or more types of sensing devices, including a camera, the sensing devices being arranged to transmit one or more types of data signals, including picture signals, to the control unit, and the control unit being arranged to assess the degree of difference of at least one type of the transmitted data signals from data signals of the same type that have previously been recorded and to maintain a record of the picture signals corresponding to the assessed data signals in the event that the degree of difference assessed is greater than a preselected threshold amount whilst avoiding the maintenance of a record of the picture signals related to the transmitted data signals - lo ⁇
  • the hardware of the apparatus can be completely conventional.
  • the camera may be a video camera, which may be of conventional design.
  • the control unit may include a microprocessor and may be a conven ⁇ tional personal computer.
  • Figure 1 is a diagram of an apparatus for generating a visual record that extends over a period of time; and Figure 2 is a flow diagram showing one example of a method of generating a visual record using the apparatus of Figure 1.
  • the apparatus shown in the drawing generally comprises a personal computer 1, a video camera 2 with a built in microphone, an analogue/digital converter 3 and three sensing devices 4A, 4B and 4C.
  • the video camera 2 is connected to a PAL video input of the computer 1 and the sensing devices 4A, 4B and 4C are connected via the analogue/digital converter 3 and a common cable 5 to respective digital inputs of the computer 1.
  • sensing device 4A is a light sensor
  • sensing device 4B is a temperature sensor
  • sensing device 4C is a sound sensor.
  • Each of the hardware units just described may be of an entirely conventional kind.
  • the camera 2 continuously transmits a picture signal (and also a sound signal) to the computer 1 where it is converted into a digital form.
  • a picture frame is stored at 240 x 180 resolution using a 256 colour palette.
  • the sensing devices 4A, 4B and 4C transmit their signals to the computer.
  • a digital recording of the picture signal would be stored in the memory of the computer at a regular, but relatively long, time interval. That mode of operation is possible with the apparatus described as is a mode in which the picture frames are recorded at as fast a rate as possible and a mode in which picture frames are recorded at, and only at, the command of a user.
  • the apparatus is, however, also arranged to store the picture frame recording only when the picture has changed materially from a previous recording; one particular example of this mode of operation will now be described in further detail.
  • the particular example described uses a 256 colour palette and the 256 colours are grouped for the purposes of assessing a change in the picture into 32 groups.
  • the latest picture frame received is analysed to determine the number of pixels in the frame of each group of colours and those numbers are compared with the corresponding numbers applicable to the last picture frame that has been stored in the memory of the computer. Only if the number of pixels of any one group have changed by more than a preselected amount (which amount may be an absolute number and/or a percentage change), then the computer will store the latest picture frame in its memory. The user is able to select the amount of change required to cause the recording of the latest picture frame.
  • the computer is also arranged to make a recording of the latest picture frame received if a preselected time has elapsed since a picture frame wa ⁇ recorded, even if there has not been a sufficient change in the picture to cause such a recording.
  • the latest picture frame is recorded for use in comparison with future frames to determine whether a new picture frame should be recorded, but it is not transferred to the memory storing the previous picture frames. In this way slow steady changes in the picture frame do not lead to the recording of new picture frames in the memory.
  • Figure 2 is a flow diagram showing the steps referred to above in summary form as a flow diagram.
  • the picture frames recorded as described above can be played back in any of three ways.
  • the frames can be played back at intervals that are in proportion to the time intervals between recording of the frames. For example, if there is a gap of 1 minute between recording of a first and second frame and a gap of 5 minutes between recording of the second frame and a third frame, the frames can be played back with a gap of 1 / 5 second between the first and second frames and 1 second between the second and third frames.
  • the frames can be played back at constant intervals regardless of the time intervals between recording of frames. In that case, in the example just given the gap between the first and second frames during playback would be the same as the gap between the second and third frames.
  • the user can select the fixed interval between frames during playback.
  • the frames can be played back one at a time at the control of the user, allowing each frame to be examined for as long as desired.
  • the readings from the sensing devices 4A, 4B and 4C are displayed digitally on the screen of the computer and the time at which the record- ing was made is also displayed.
  • a facility is also provided to enable the readings to be displayed graphically.
  • changes in the signals from the devices 4A, 4B and 4C have no influence on whether or not a new set of recorded data is stored in the memory of the computer. It is, however, possible to make the decision as to whether or not to store a new set of recorded data dependent on an assessment of the amount of change in the signals from one or more of the devices 4A, 4B and 4C as well as, or instead of, on the amount of change in the picture signal.
  • the computer may be arranged to store a new set of recorded data in the event that the temperature, as indicated by the sensing device 4B, is more than 1°C different from the temperature last recorded.
  • the computer can also be instructed to look at a combination of changes: for example, a modest change in the picture frame, which would not itself be sufficient to cause the computer to store a new set of recorded data, can be arranged to cause such storing of new data if at the same time there is a change in temperature recorded by the sensing device 4B of more than 0.5°C. Changes in the sound input from the sensing device 4C, or from the microphone of the camera 2, may be analysed by techniques known per se and the amount of change in the signal analysed in a manner analogous to that already described with reference to the picture signal.
  • sensing devices 4A, 4B and 4C are given merely by way of example. Instead or in addition to those devices, other sensors that are able to provide an electrical analogue or digital output can be employed.
  • the present invention can be performed satisfac ⁇ torily employing a personal computer with a 486 DX2-50 microprocessor having 8Mb RAM and a 520Mb hard disc drive. With such equipment we have found it possible to store up to 1200 picture frames at 240 x 180 resolution as well as data from the sensors 4A, 4B and 4C.
  • the present invention can be employed in a wide variety of applications. Some of those applications will be mentioned below by way of example.
  • the study of animal behaviour video logging as described above enables a study of animal behaviour to be carried out for a long period with minimal use of memory space during periods of inactivity but detailed recording during active periods.
  • Time and motion studies in a workplace usage of office equipment or manufacturing machinery can be studied, again without wasting memory space on recording during periods when the equipment or machinery is not in active use.
  • Process monitoring it is already known to use certain sensors specifically to monitor a malfunction or breakdown in, for example, a manufacturing process; the use of video logging as described above will enable a much more complete picture of such events to be obtained right from the start of the event, even though it is unexpecte .
  • Security applications conventional security monitoring relies on infrequent video frame capture at regular intervals; the use of video logging as described above will enable many more video frames to be recorded during an incident but none when all is quiet, thus enabling a large collection of useful data to be acquired without recording an unmanageably large total amount.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Multimedia (AREA)
  • Television Signal Processing For Recording (AREA)

Abstract

Procédé et dispositif servant à générer un enregistrement visuel s'étendant sur une durée déterminée. Des signaux de données sont transmis à un ensemble de commande (1), ces signaux comprenant des signaux d'image émis par une caméra (2) et des signaux provenant d'un ou plusieurs types de dispositifs de détection (4A, 4B, 4C). Seul un enregistrement de quelques uns des signaux d'image est retenu. Le degré de différence entre au moins un type des signaux de données transmis et des signaux de données du même type ayant été enregistrés précédemment est évalué et seulement quand le degré de différence évalué est supérieur à un seuil présélectionné, un enregistrement des signaux d'image est retenu.
PCT/GB1996/002955 1995-11-30 1996-11-29 Procede et dispositif servant a generer un enregistrement visuel Ceased WO1997020293A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE69608123T DE69608123D1 (de) 1995-11-30 1996-11-29 Verfahren und vorrichtung zur speicherung eines bildes
EP96940029A EP0864140B1 (fr) 1995-11-30 1996-11-29 Procede et dispositif servant a generer un enregistrement visuel

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9524538.7A GB9524538D0 (en) 1995-11-30 1995-11-30 Method and apparatus for generating a visual record
GB9524538.7 1995-11-30

Publications (1)

Publication Number Publication Date
WO1997020293A1 true WO1997020293A1 (fr) 1997-06-05

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PCT/GB1996/002955 Ceased WO1997020293A1 (fr) 1995-11-30 1996-11-29 Procede et dispositif servant a generer un enregistrement visuel

Country Status (4)

Country Link
EP (1) EP0864140B1 (fr)
DE (1) DE69608123D1 (fr)
GB (1) GB9524538D0 (fr)
WO (1) WO1997020293A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10214077B4 (de) 2001-03-28 2018-07-26 Sanyo Electric Co., Ltd. Bildsuchgerät

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4408224A (en) * 1980-05-09 1983-10-04 Hajime Industries Ltd. Surveillance method and apparatus
EP0221631A2 (fr) * 1985-10-24 1987-05-13 Videoscan Limited Procédé et appareil pour la surveillance d'événements
DE3827928A1 (de) * 1988-08-17 1990-02-22 Standard Elektrik Lorenz Ag Bildfernsprechgeraet
EP0445334A1 (fr) * 1990-03-08 1991-09-11 Siemens Aktiengesellschaft Procédé de détection d'intrus
EP0467094A2 (fr) * 1990-06-21 1992-01-22 Fujitsu Limited Méthode et dispositif de surveillance pour transmettre des informations au moyen d'une technique de mode de transfert asynchrone en RNIS à large bande
GB2253534A (en) * 1991-02-02 1992-09-09 Advanced Technology Ind Limite A remote camera monitoring system
EP0528105A1 (fr) * 1991-08-15 1993-02-24 Pioneer Electronic Corporation Système de surveillance d'image
WO1993019467A1 (fr) * 1992-03-26 1993-09-30 Solid State Logic Limited Detection de changements de scene

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4408224A (en) * 1980-05-09 1983-10-04 Hajime Industries Ltd. Surveillance method and apparatus
EP0221631A2 (fr) * 1985-10-24 1987-05-13 Videoscan Limited Procédé et appareil pour la surveillance d'événements
DE3827928A1 (de) * 1988-08-17 1990-02-22 Standard Elektrik Lorenz Ag Bildfernsprechgeraet
EP0445334A1 (fr) * 1990-03-08 1991-09-11 Siemens Aktiengesellschaft Procédé de détection d'intrus
EP0467094A2 (fr) * 1990-06-21 1992-01-22 Fujitsu Limited Méthode et dispositif de surveillance pour transmettre des informations au moyen d'une technique de mode de transfert asynchrone en RNIS à large bande
GB2253534A (en) * 1991-02-02 1992-09-09 Advanced Technology Ind Limite A remote camera monitoring system
EP0528105A1 (fr) * 1991-08-15 1993-02-24 Pioneer Electronic Corporation Système de surveillance d'image
WO1993019467A1 (fr) * 1992-03-26 1993-09-30 Solid State Logic Limited Detection de changements de scene

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Selective Video Event Recorder", I.B.M. TECHNICAL DISCLOSURE BULLETIN, vol. 28, no. 9, February 1986 (1986-02-01), ARMONK,NEW YORK, USA, pages 3801 - 3802, XP002027005 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10214077B4 (de) 2001-03-28 2018-07-26 Sanyo Electric Co., Ltd. Bildsuchgerät

Also Published As

Publication number Publication date
EP0864140A1 (fr) 1998-09-16
EP0864140B1 (fr) 2000-05-03
GB9524538D0 (en) 1996-01-31
DE69608123D1 (de) 2000-06-08

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