CA2136054C - Method and device for the determination of radio and television users behaviour - Google Patents

Abstract

In order to determine the audience behaviour, hearing samples are taken at certain moments. These hearing samples are able to perceive the sound impressions actually received by a test person. This test persons carries a portable monitor. Furthermore, the broadcast receiving devices may bear such monitors, a direct electrical connection with the monitor being possible besides the acoustic recording of the hearing samples. The hearing samples are converted into digital form by adequate methods, then compressed and optionally encoded. In greater time intervals, the hearing samples are transmitted to a center where the hearing samples are correlated with program samples taken simultaneously from the monitored programs.

Description

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METHOD AND DEVICE FOR THE DETERMINATION OF RADIO
AND TELEVISION USERS BEHAVIOUR
The present invention belongs to the field of broadcast audience research. It is particularly referred to a method for the determination of the pro-gram actually listened.
Background of the Invention In the field of television audience research, a number of different methods have become known for de-termining the actually received and displayed program and the identity of the viewers which follow the dis-played program. The feature of identifying program portions recorded on video recorders and displayed later on has also been realized.
Although evident and in principle capable of be-ing realized, such methods cannot be put into practice in the field of radio broadcasting. One reason there-for is that each television set is monitored which is justified under the condition that each family owns a small number of TV sets only (one or two, as a rule) which have a fixed place. In this case, relatively expensive monitoring devices may be provided which are adapted to the actual set.
In contrast thereto, several radio sets are ex-isting in most cases in a household which are some-times also operated outdoors. Examples thereof are car radios, walkmen and portable sets. Furthermore, T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) radio is often passively listened in department stores, supermarkets, restaurants, etc. In addition, the frequency ranges of the radio programs are not the same all over a country. Thus, in order to determine a program actually listened from the tuning of a radio set, it would be necessary to determine the actual place of listening, too, and to determine the displayed program during evaluation from a voluminous list of program transmission frequencies which has continuously to be updated.
US-5 023 929 describes an appliance that is used for recording hearing samples of a duration of e.g. 3 seconds every 10 minutes. The ambient noise samples are recorded on magnetic tape in an uncompressed state.
Thus, the apparatus must be carried by the participant in the survey at all times, which amounts to a certain complication on account of its size and weight and may be awkward in the long run. Moreover, it is possible for the participant to forget to carry the appliance, in which case the survey will be incomplete.
EP-A-299 711 indicates a compression method for digital audio data. The method allows a high-quality restoration of an acoustic signal from the compressed data stored in a semiconductor memory by decompression, inter alia. However, the information content is not reduced in this compression method. Therefore, it requires a relatively large amount of memory, thereby again resulting in a relatively voluminous construction if uninterrupted operation of monitoring over several days is intended. It will also be noted that the energy consumption increases with the memory capacity.

Thus, a monitoring of the radio reproduction and the determination of the received radio program from the tuning of the receiver, which is usually done with television sets, is not practical with radio receivers.
There is an object of the present invention to provide a method for the determination of the behavior of persons watching a radio or television program which permits the determination of the attended radio or television program, independently of the whereabouts of the person.
Summarv of the Invention This object is attained by a method which comprises recording and storing acoustical hearing samples from the environment of the listener, the hearing sample recordings being made at predetermined times, and/or storing of information identifying the recording time, together with the hearing sample, the recorded signal being digitalized and then stored in a non-volatile memory device being free from mechani-- 2a -._ 21~60~~:
cally movable parts which are important for the storage; such memory devices are for example non-volatile or battery buffered semiconductor memory devices.
In the following, broadcast receiver shall be construed as encompassing radios, TV sets and other broadcast receiver devices bringing forth acoustically recognizable sound by an attendant.
According to this method, hearing samples are re-corded in the environment of a listener and then stored in order to correlate them later on with the corresponding recordings of one or more transmitted programs. For this correlation, information about the time is recorded too, or the hearing samples are re-corded within a predetermined time frame whose start-ing time is defined or, e.g., stored at the beginning of the recording of the hearing samples. In order to reduce the memory volume necessary for storing the hearing samples, it is preferred to record and to store only at predetermined times and each time only during short time intervals.
The corresponding appliance, called monitor in the following description, may be attached to a broad-cast receiver, or it may be carried by the test per-son. The first variant requires the determination of who listens to the broadcast receiver and if the broadcast receiver is listened at all, i.e. the listener must be in sufficient proximity to the broad-cast receiver. This may also be done by an input in the monitor, e.g. through a keyboard, a coded card, or T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) also by coded transmitters borne by the persons in the test household.
The second variant, namely the monitor borne by the test person, allows straight away to determine what the carrier of the monitor listens at the moment.
A condition for this method is a small and lightweight monitor which may for example be carried in a shirt pocket. The monitor must function over a sufficiently long time period. This requires on one hand a suffi-ciently high memory capacity and, on the other hand, the use of batteries as a power source since the monitor is portable, optionally supported by solar cells or other power sources accessible in mobile op-eration. In order to use these energy sources as eco-nomically as possible, the hearing samples are exclu-sively stored in memory devices which do not contain mechanically movable components, thus in particular no magnetic tapes, etc.
The memory means to be used, such as non-volatile or battery buffered semiconductor memories, have how-ever a limited capacity only and are only able to store digital data. Thus, appropriate methods for storage in a form as compressed as possible and a highliest possible reduction of data volume are neces-sary. The recording of short hearing samples only, interrupted by relatively long time intervals, already reduces substantially the amount of data to be stored.
A further reduction may be obtained by limiting the recording to a predetermined frequency band within the region of audible frequencies, i. e. the audio band.

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After the analog to digital transformation, fur-ther compression methods may be applied which may be performed by a processor, namely in using the dif-ferent data compressing methods known from the digital techniques and generally applicable, as well as trans-formations such as the (Fast) Fourier transformations.
The degree of data reduction can be controlled by the density of the support sites.
A further aspect is the data and personality pro-tection. It is foreseeable that test persons will not like to carry about or even have in their neighborhood an appliance which is able to record and to store any spoken word, too. The method of the invention already provides a protection as it stores short hearing peri-ods only. The further processing steps already menti-oned such as reduced monitored frequency band and the application of transformations, further make the trac-ing of a discussion more difficult. Finally, the data may additionally be encoded prior to the storage, pre-ferably by an irreversible process.
The determination of the program actually listen-ed is made by comparing the hearing samples with the simultaneously recorded program samples. Program samples may be taken in the broadcast studio, at any point of the transmitting installation or also in a cable receiving installation where the channels are definitely related to a particular program. This sam-pling need not be made through an acoustic interface but can be achieved in any other way whatsoever. It is essential that the hearing samples are recorded overlapping in time with the program samples, and that the recorded data can be brought in such a form that T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) 213~fl~4 they can be checked for correspondence by a correla-tion process. The program samples may be immediately submitted to the same procedures as the hearing samples. Another possibility is to store the program samples first as a raw version and to adapt them at the moment of correlation to the hearing samples. By this way, program samples can be correlated to stored hearing samples which have been compressed, trans-formed and/or coded in different ways.
A precondition is that the recording time of the hearing samples and of the program samples can be determined at the time of correlation. This is achieved in the most simple way in storing the begin-ning time of the recording together with the samples.
In a series of samples recorded one after the other, it may be sufficient to store the real time and to store afterwards only the time intervals between two successive samples, or to calculate the recording times of the further samples in supposing a sample recording at regular time intervals.
The correlation of the hearing samples with the program samples is made in a center. The transmission of the hearing samples from the test households may be effected in different manners. Due to the small dimensions of the monitors, these may be sent directly by mail to the center. It is possible to install a device in the test households which is able to read the memories of the monitors and which transmits the data to the center by a modem. Optionally, a televi-sion audience measurement system is already installed in such a testing household. Such systems often al-ready comprise a modem connected to a center for data T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) 23'444-347 transmission. Then, the data of the monitors can also be transmitted to the center, e.g. by means of a special adapter, over that measurement system.
The recording of the program samples can be achieved by appliances similar to the monitors. Since these appliances are stationary in most cases, a direct recording of the program signal, i.e. without a detour through acoustic reproduction, is applied, and storage is possible during longer recording intervals since the program sampler may comprise more complex memory means of higher capacities.
This allows the compensation of time shifts between hearing samples and program samples during the subsequent correlation procedure due to not exactly synchronous time bases without shortening the effective correlation interval.
According to one aspect, the invention provides a method for the identification of a hearing impression which is perceived by a listener, the method comprising the recording and storing of hearing samples taken from the environment of the listener, the hearing sample recordings being made at predetermined times or being stored together with information about the recording time, the hearing sample in the form of a recorded signal being digitized, compressed to obtain a data rate of 100 Bytes/Min. at the most, and then stored in a non-volatile memory device being free from mechanically movable parts which are functionally important for the storage, thereby allowing these steps of the method to be performed by an appliance that is discreetly carried by the listener.
According to another aspect, the invention provides a device for carrying out a method in accordance with those disclosed herewith, the device comprising: a microphone, at least one component for the filtering out of _ 7 _ 23'444-347 a frequency band; an analog to digital converter; a processing unit for the digitized data, the processing unit applying at least one compression method to the digitized data such that the digitized data are available at its output at a rate of 100 Bytes/Min. at the most; and a non-volatile memory for digitized, compressed data, the memory free from mechanically movable components which are important for the storing process; wherein the device includes a timing unit for determining the time of the hearing samples, and wherein the device is designed so small and light that it may be discreetly carried by a person.
According to another aspect, the invention provides an installation comprising a device in accordance with those disclosed herewith, wherein the installation comprises a second microphone, a transmitter being connected to said second microphone, said second microphone for wireless emission of the signal received by the second microphone, the device further comprising a receiver for this signal.
According to another aspect, the invention provides a method for determining the behaviour of listeners or viewers, comprising the following steps: collecting hearing samples in accordance with methods thereof disclosed herewith; generating and storing program samples from at least one radio or television program, which overlaps in time at least in part with said hearing samples, said hearing samples and said program samples being subjected to the same processing steps between recording and storing, and correlating at a later time, temporally corresponding hearing samples and program samples, a positive correlation result indicating consistency between the program captured by the hearing samples and that captured by the program samples.
- 7a -23'444-347 Brief Description of the Drawings The invention will now be explained further by means of an exemplary embodiment thereof and with the aid of the drawings wherein:
FIGURE 1 shows the function principle by means of a circuit block diagram, and FIGURE 2 shows a circuit block diagram in more detail.
Detailed Description of the Invention The audio signal coming from microphone 1 is passed through the band pass 2 which filters a frequency range of from 100 to 4000 sec-1, preferably from 300 - 7b -to 3000 sec-1, out of the whole audio frequency range.
The band width limited signal is passed to the analog to digital converter 3 and then, in digital form, into a first intermediate memory 4. The analog to digital converter is controlled by a timer or clock 9. This clock switches the analog to digital converter on dur-ing one second at the beginning of every minute. The clock 9 comprises a quartz time base which is syn-chronized with a time base in the center.
The hearing sample stored in the memory 4 in digital form during the recording time of one second is read during the recording free remainder of the minute and stored in memory 8 after Fourier trans-formation in the Fourier transformer unit 5, compres-sion in the compressor 6, and encoding in the encoding unit 7.
Possible embodiments are for example the execu tion as a credit card, a clip or also integrated into a watch.
The monitors which are distributed in the test household are put once a day into a charging and syn-chronizing station which is existing once in the household. The synchronizing station will synchronize the clocks 9 in the individual monitors. It is also able to read the memory 8 from each monitor and to store the contents of the memory 8 in an own memory of higher capacity which may also be a tape recorder.
The memory of the monitor is preferably erased there-after. As a further function, the synchronizing sta-tion may charge the rechargeable energy sources of the monitor.
- g -T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) The data transmission to the center may be ef-fected in that, for example during the night, the charging and synchronizing station is called up by the center, or the station calls the center computer up, whereupon it transmits the stored. data on request.
The clock existing in the charging and synchronizing station may then be synchronized with the time base of the center computer, too. The connection with the center is built up either through an own modem or through a modem of an already existing installation for TV audience research. The second possibility con-sists in sending the data carrier of the charging and synchronizing station to the center. Finally, the monitors themselves can be sent to the center, and the clock incorporated into the monitors can then be syn-chronized with the time base of the center.
The monitor can be adapted in different manners to the prevailing conditions. In particular, the dif-ferent processing procedures can be effected by only one processor. When the recording time is only 1 sec-ond per minute, it has 59 seconds to effect the trans-formation, the compression and the encoding. The car-rying out of all these operations by a processor addi-tionally presents the advantage that a variation of the overall function may be achieved by changing just the program which controls the processor. For exam-ple, the encoder or its code may be exchanged, the compression can be switched on and off, and other transformation techniques may be used.
The filter 2 may also be a digital one and will then be positioned after the analog to digital con-T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) 21360~~
verter. In the same manner, the filtering may be ef-fected by a processor digitally. The sequence of the functional elements may also be selected in another manner.
The synchronizing of the time base 9 may be left out when the time base 9 contains a receiver for a standard time signal, e.g., DCF-77, which is also used by the program samplers as a time standard.
A problem with the purely acoustical recording of the hearing sample is a possibly too high ambient noise level. A possible solution consists in attach-ing so-called minispies to the loudspeakers which take up the body sound of the loudspeaker and transmit it directly to the monitors, for instance by means of radio signals, infrared or ultrasound radiation. The monitor may also be connected directly to the loud-speaker or to the headphones output of e.g. a walkman.
A monitor may also be attached stationarily to a hi-fi stereo set by means of an adapter that enables the input of the listening persons. The monitor could also be equipped with a button allowing its deactiva-tion, for example during a confidential talk.
A preferred embodiment will now be described with reference to FIG. 2. The monitor, namely the hearing sampler carried by the listener, is integrated into a watch, preferably a wrist watch. The microphone 1 has a high to a very high sensitivity within the frequency range of from about 200 s-1 to 3000 s-1 for the sound waves 11, outside of this range only a low one. The microphone acts thus as a preliminary filter. The deviation 13 for the feeding in of signals instead of T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) or additionally to the recording by the microphone 1 will be described later.
The signal 14 already limited as to band width (about 200 to 3000 s-1) coming from the microphone is fed to an amplifier and band pass 15 which raises the signal to the level necessary for the following analog to digital converter 3 and effects the band width limitation with the desired sharpness. The output signal 18 of the amplifier 15 is passed to the analog to digital converter 3 which converts it into a digitalized form 20. The conversion is effected with a scanning rate of 6000 s-1 and a resolution of 8 bits (= 1 byte) per scanned value. The transmission of the output signal during the scan interval is effected by the switch 22. Since the scanning interval is one second, 6000 values (= 6000 byte) will be passed to the intermediate memory 4. Switch 22 and analog to digital converter 3 are controlled by the timer or clock 9 which may be coupled to the time display of the watch or works independently thereof, the clock 9 providing the scan rate signal 24 of 6000 s-1 to the analog to digital converter 3 and the switch signal 25 to the switch 22 during a time period of 1 s in every minute.
The data 29 are read out of the intermediate memory 4 by the Fourier transformer unit 5. This Fourier transformer unit works on time segments of 200 ms each of the one second hearing samples so that five Fourier coefficient sets 30 are produced as a result of each scanning interval which are stored in an in-termediate memory 32.

T:\KG\TEXTE\UEBERSET\25121US(ST/DM/s 11.11.94) 2136Q~4 From this memory, the Fourier coefficients 34 are fetched by the data compressor 6 and reduced in volume by one of the current compression techniques such as Huffmann encoding, Lempel-Ziv-Welch method, etc.
without information losses. Compressions up to 2/5th of the input data amounts may be obtained or even more if more powerful techniques will become known and available. An experienced value is that about 100 byte of compressed data are produced per scanning in-terval, i.e. per minute. The compressed Fourier transformation data sets 37 are stored in a non-volatile memory 8, e.g. a flash EPROM, having a capac-ity of, e.g., 1 MB (= 220 byte). This capacity allows at a data flux of 100 byte per minute an uninterrupted wearing time of the watch of several days until the readout of the memory. When the memory capacity will further be increased by the development of the art, this time period will be increased, too.
At least the Fourier transformer unit 5 and the data compressor 6 are realized by a processor under the control of corresponding programs. The processor may take over, at the same time, the above mentioned encoding, if necessary.
The reading of the data out of the EPROM 8 and their deletion is effected in the charging and syn-chronizing station 39 in which the watch containing the monitor may be placed. The transmission of energy and data is effected without contacts by an elec-tromagnetic coupling, thus avoiding the opening of the watch, and the charging and reading out requires only little efforts of instruction of the operator and can therefore made by the test person himself or herself.

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The monitor in the watch comprises, for the contact with the charging station 39, the following functional elements: reading control 40 and reset and erase con-trol 41 for reading and erasing the memory 8; a clock synchronisation unit 42 for synchronizing the monitor claock 9, and a battery charging unit 43 which con-tains the supply battery of the monitor and serves to charge this battery. The data transmission is preferably a serial one.
The synchronisation of the clock 9 is necessary since the 200 ms partitions od the one second samples must be able to be correlated exactly in time to the samples taken in the broadcast station which may cause problems even with a quartz time base in the course of days. For the compensation of one of the most impor-tant influence factors, the temperature, the tempera-ture dependence of the clock 9 is determined and stored for each monitor. By means of a temperature sensor thermally coupled to the clock 9, especially to its quartz, the time deviation caused by temperature influences may be determined and corrected; a preci-sion of ~ 200 ms time error per week can thus be ob-tained.
Further possible additional devices are a per-sonal identification unit 45, a "wearing" detector 46, an attentiveness key 48 or similar for entering a listening with particular attention, etc. The per-sonal identification 45 is fixed as the user'code. It will also be possible to provide several codes which can be selected by means of actuating elements of the watch.

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The "wearing" detector 46 serves for the auto-matic detection whether the watch, i.e. the monitor, is worn by the test person, and the hearing samples correspond thus to the hearing impression of the listener. As a secondary function, the acoustic su-pervision may be turned off when the wach is not worn, e.g. by night. The detector 46 may be constructed as an inductive or a capacitive sensor which reacts, for example, on the proximity to the body of the test per-son or to the condition of the strap of the watch (open or closed).
The attentiveness key 47 serves to allow the test person to manually note phases of increased attention.
The comparative hearing samples which are re-corded at the broadcast station, e.g. in the studio, are treated and stored by a functionally identical monitor. However, the signal is supplied not from the microphone 1 but over the deviation 13 directly to the input of the amplifier 15. The final storage is made on a memory device having a high capacity, as usually employed in the computer technique, e.g. on the base of magnetic tapes. The functions necessary for the portable and automatic operations such as the inter-face units to the charging and synchronizing station, the attentiveness key, the "wearing" sensor, etc., are not provided in this case.
The invention can also be used for the determina-tion of the user behaviour for other kinds of trans-mission having an acoustic component such as televi-sion or the like.

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Claims (28)

1. A method for the identification of a hearing impression which is perceived by a listener, the method comprising the recording and storing of hearing samples taken from the environment of the listener, the hearing sample recordings being made at predetermined times or being stored together with information about the recording time, the hearing sample in the form of a recorded signal being digitized, compressed to obtain a data rate of 100 Bytes/Min. at the most, and then stored in a non-volatile memory device being free from mechanically movable parts which are functionally important for the storage, thereby allowing these steps of the method to be performed by an appliance that is discreetly carried by the listener.

2. A method according to claim 1 wherein the hearing impression which is perceived by the listener is of a broadcast program.

3. A method according to claim 2 wherein the broadcast program is one of a radio program and a television program.

4. A method according to any one of claims 1-3, wherein hearing samples are determined by recording acoustic signals with or without ambient noise at predetermined times during a recording interval, this recording interval being substantially smaller than the time period between two recording times, the recording interval being from 0.1 to 10 seconds.

5. A method according to any one of claims 1-3 wherein hearing samples are determined by recording acoustic signals with or without ambient noise at predetermined times during a recording interval, this recording interval being substantially smaller than the time period between two recording times, the recording interval being from 0.5 to 2 seconds.

6. A method according to claim 4 or 5, wherein the recording interval is divided into partial intervals, and the data of the hearing samples of these partial intervals are determined and stored independently of each other.

7. A method according to any one of claims 1-6 wherein a frequency band of from about 100 s-1 to 4000 s-1, is filtered out of the hearing sample.

8. A method according to any one of claims 1-6 wherein a frequency band being entirely within from about 300 s-1 to about 3000 s-1 is filtered out of the hearing sample.

9. A method according to any one of claims 1-8, wherein the recorded signal is subjected to a transformation, in particular to a Fourier transformation, a Fast Fourier transformation, or a Laplace transformation.

10. A method according to any one of claims 1-9, wherein the storage is effected in non-volatile or battery buffered semiconductor memory.

11. A method according to claim 10 wherein the storage is effected in an electrically erasable permanent memory.

12. A method according to any one of claims 1-11, wherein encoding is applied to the digitized signal prior to storage.

13. A method according to claim 12 wherein the encoding applied is an irreversible encoding.

14. A device for carrying out the method according to any one of claims 1-13, the device comprising:
- a microphone, - at least one component for the filtering out of a frequency band;
- an analog to digital converter;
- a processing unit for the digitized data, the processing unit applying at least one compression method to the digitized data such that the digitized data are available at its output at a rate of 100 Bytes/Min. at the most;
- a non-volatile memory for digitized, compressed data, the memory free from mechanically movable components which are important for the storing process; and - a timing unit for determining the time of the hearing samples;
- the device being designed so small and light that it may be discreetly carried by a person.

15. A device according to claim 14 wherein the processor is capable of program controlled processing.

16. A device according to one of claims 14 and 15 wherein the non-volatile memory is a non-volatile or battery buffered semiconductor memory.

17. A device according to any one of claims 14-16 wherein the device is in the form of any one of a wristwatch, a clip, and a cheque card.

18. A device according to any one of claims 14-17, wherein the non-volatile memory is an electrically erasable permanent semiconductor memory.

19. A device according to claim 18 wherein the non-volatile memory is of the FLASH EPROM type.

20. A device according to any one of claims 14-19, wherein the timing unit comprises a real time base capable of being adjusted to a reference time base by means of a synchronizing unit, said real time base being provided with at least one correction unit for correcting time deviations caused by temperature changes, said correction unit responding to the temperature in the proximity of said time base.

21. A device according to any one of claims 14-20, wherein said timing unit contains a receiver and a decoder for standard time signals.

22. A device according to any one of claims 14-21, wherein the device is transportable and capable of being carried by a test person and comprises a capacitive or inductive sensor for generating a signal indicating that it is being carried by said person.

23. An installation comprising a device according to any one of claims 14-22, wherein the installation comprises a second microphone, a transmitter being connected to said second microphone, said second microphone for wireless emission of the signal received by the second microphone, the device further comprising a receiver for this signal.

24. An installation according to claim 23 wherein the second microphone is an impact sound microphone attached to a loudspeaker of a broadcast receiver.

25. An installation according to one of claims 23 and 24 wherein the second microphone is fastened to a speaker of a radio or television receiver.

26. A method for determining the behaviour of listeners or viewers, comprising the following steps:
- collecting hearing samples according to the method of any one of claims 1-13;
- generating and storing program samples from at least one radio or television program, which overlaps in time at least in part with said hearing samples, said hearing samples and said program samples being subjected to the same processing steps between recording and storing, and - correlating at a later time, temporally corresponding hearing samples and program samples, a positive correlation result indicating consistency between the program captured by the hearing samples and that captured by the program samples.

27. A method according to claim 26, wherein the program samples are subjected prior to their storage to a first series of said processing steps, and are subjected to further processing steps between their readout from the memory and said correlation, in order to bring the program samples in condition for the correlation with the hearing samples.

28. A method according to claim 27 wherein the program samples are subjected to an encoding.