EP0598682B1 - Method for evaluating behaviour of radio listeners, and apparatus therefor - Google Patents

Abstract

To evaluate the audience behaviour to radio or TV programmes, listening samples are taken at particular times. These listening samples can detect the sound impressions actually received by a test person, on the one hand. For this purpose, the test person carries a portable monitor on his person. Furthermore, the receiving sets themselves can also carry such monitors, in which arrangement, apart from the acoustic pick-up of the listening samples, a direct electrical connection to the monitor is also possible. The listening samples are converted into digital form, compressed, transformed and, if necessary, coded by adequate methods. The listening samples are transmitted at relatively large time intervals to a central station where the listening samples are correlated with samples from the monitored programmes which are picked up at the same time. <IMAGE>

Description

The present invention relates to the field of Radio listener behavior research, and in particular on one Procedure for determining the program you are listening to.

In the field of television audience research there are many different ones Process known to the respective received and reproduced Program and determine the identity of viewers who are watching the program being played. Also the ability to record and record on VCRs parts of the program reproduced at a later date identify was realized.

Although obvious and in principle can also be used these methods are impractical in the field of radio. On The reason is that every television set is monitored, what makes sense from the effort under the premise that a small number of televisions per household (in the Usually one or two) are present that have a fixed location to have. Then can be relatively complex and to the respective Monitoring devices to be adapted must be attached.

In contrast, there are usually several radio sets in one household available, some of which are also used outside become. These include car radio, Walkman, Portable radio. In addition, in department stores, supermarkets, Restaurants etc. often listened to the radio. In addition are the frequency ranges of the radio programs are not nationwide established. To get that from the setting of a radio to determine received program, it would be necessary, too determine the current location, and when evaluating about a large and constantly up to date List of regional program broadcast frequencies that are reproduced To determine the program.

Monitoring the playback of the devices and the at TV receivers usually determine the received radio program from the setting of the recipient is therefore at Radio receivers do not make sense.

US-5,023,929 specifies a device with which hearing samples of e.g. 3 seconds every 10 minutes. The ambient noise tests are uncompressed on a magnetic tape recorded. This device is therefore from each Participants in the study, what because of size and Weight means a certain circumstance that lasts can become uncomfortable. The device can also forget gaps in the investigation.

EP-A-299 711 gives a compression method for digital Audio data. The process allows the compressed, data stored in a semiconductor memory with high Quality back in an acoustic signal by Convert decompression back. This compression process however, does not reduce the information content. It therefore requires a relatively large amount of memory, which in With regard to the uninterrupted operation of a monitor from some days again leads to relatively voluminous designs. It should also be borne in mind that with the Storage size also increases the energy requirement.

An object of the present invention is a method to determine the radio listening behavior, the determination of the radio program listened to independently allowed from the listener's location.

A method that solves this problem is in claim 1 specified. The further claims contain preferred embodiments, Devices for performing the method and applications of the method.

Accordingly, acoustic auditions in the vicinity of a Handset recorded and saved to a later Time with corresponding recordings of one or more Programs to correlate. For correlation is with the Information about the point in time is saved, or the audio samples are pre-defined Time grid added, whose start time defines or z. B. is stored at the beginning of the audio sample recording. To reduce the memory required for the audio samples becomes advantageous at certain times and only recorded and saved over a short time interval.

The corresponding device, hereinafter referred to as the monitor, can once attached to the radio receiver, and on the other also be carried by the test person. The former Variant assumes that it is also determined whether and whoever listens to the radio, d. H. is close enough. This can be done by entering on the monitor, such as. B. using a keyboard, a code card or a barcode reader, or even through code transmitters by the people to be worn in the test household.

The second variant, the monitor carried by the test person, allows you to easily determine what the The wearer of the monitor is listening. requirement for this procedure is a small and easy one Monitor, e.g. B. also worn in a shirt breast pocket can be. The monitor needs to be long enough be functional. This requires a sufficiently high one Storage capacity, and on the other hand because of the mobile operation a power supply from batteries, possibly supported by solar cells or others, in mobile operation accessible energy sources. To these energy sources The auditions will only be used as economically as possible recorded on storage media that do not have mechanical components, in particular none Magnetic tapes etc.

The applicable storage media, such as non-volatile or battery-backed semiconductor memories, but have only limited Capacity and can generally only digital Save data. Suitable methods for the most compact possible Storage and reduction of the data volume are therefore necessary. The recording of only short samples, interrupted by contrast, relatively long time intervals, reduced already significantly the amount of data to be saved. A further reduction can be made by restricting it to one reduced frequency band within the range of audible Frequencies of the audio tape.

After the analog-to-digital conversion, further compression methods can be used applied by a processor can be executed. These include those from digital technology known, generally applicable data compression methods, as well as transformations, such as the (fast) Fourier transformation. Here is the level of data reduction can be set by the density of the support points.

Another aspect is data and privacy protection. It is predictable that test subjects will not be happy are ready to carry a device with them, or even just in to have in their environment, including what is spoken Listen to the word and record it. In the inventive Procedure is already through storage protection against this is given only by brief auditions. The others mentioned processing steps, such as reduced monitored Frequency band and application of transformations further complicate tracking of a conversation. Finally, the data can still be saved are additionally encrypted, preferably according to a irreversible process.

The program being listened to is determined by comparing the audio samples with those recorded at the same time Program samples. Program samples can e.g. B. in Broadcasting studio, at any point of the broadcasting system or also in a cable reception system, where the assignment of the Channels defined for a program can be removed. This does not have to be done via an acoustic intermediate stage, but can be done in any way. Essential is that the audio samples overlap with the Program samples are recorded and that the recorded Data can be brought into a form in which they match by a correlation process can be checked. The program samples can be started immediately subjected to the same procedures as the auditions become. Another possibility is that the Program samples are first saved in a raw version and only at the moment of correlation to the audio samples be adjusted. This means that program samples can also be used for Correlation with stored samples can be used which have been compressed, transformed and / or encrypted in various ways.

The prerequisite is that the time of the recording of the audio samples and the program samples at the time of correlation can be determined. The easiest way to do this is that along with the samples also the beginning of the Recording is saved. In a series in a row recorded samples may also suffice, only once save the absolute time and only later record the time intervals between two samples, or from the saved time under the assumption a regular sampling the times of the other Calculate samples mathematically.

The audio samples are correlated with the program samples in a headquarters. The transmission of the audio samples from the test households to the headquarters can be different Species. Because of the small size of the monitors these are sent directly to the headquarters by post. A device can also be installed in the test households that the memory of the monitors can read and the Transmits data to the headquarters via modem. Maybe in such a test household already has a system for Determination of television habits installed. such Systems often already include a modem with a data connection to a headquarters. Can use this system then z. B. using a special adapter also the data the monitors are transferred to the control center.

The recording of the program samples can be similar by devices the monitors. Because these devices in most cases are stationary, a direct decoupling of the program signal, without detour via acoustic reproduction, applied, and it can also be used during longer exposure intervals be recorded as the program sampler contain more expensive storage media of higher capacity can. So z. B. Time shifts between Audio samples and program samples as they do not come from can result in exactly synchronous running time bases, while the correlation subsequently compensated for the recording without shortening the effective correlation interval would.

Figur 1

zeigt anhand eines Blockschaltbilds das Funktionsprinzip, und

Figur 2

zeigt ein mehr in Detail gehendes Blockschaltbild.

The invention is to be further explained using an exemplary embodiment with reference to figures.

Figure 1

shows the principle of operation using a block diagram, and

Figure 2

shows a more detailed block diagram.

From the microphone 1, the audio signal reaches the bandpass filter 2, which filters a frequency range from 100 to 4000 s ^-1 , preferably 300 to 3000 s ^-1 , out of the entire audio frequency range. The bandwidth-limited signal goes further to the analog-to-digital converter 3 and from there further in digital form to a first buffer memory 4. The analog-to-digital converter is controlled by a timer 9. This timer turns on the analog-to-digital converter for one second at the beginning of every full minute. For this purpose, the timer 9 has a quartz time base which is synchronized with a time base in the control center.

The during the one-second recording time in the memory 4 in The audio sample saved in digital form is recorded in the non-recording Read the rest of the minute from memory 4 and after Fourier transform in the Fourier transform unit 5, compression in the compressor 6 and encryption in the Encryption unit 7 stored in memory 8.

Conceivable embodiments are, for example, as a check card or clip or also integrated in a watch.

The monitors in the test household will be checked once on Day in a charging and synchronization station that is once available in the household inserted. The synchronization station ensures once for a synchronization of the timers 9 in each Monitors. It can also store from any monitor 8 read out and stores the content in its own, larger-sized memory, which also z. B. a tape deck can be. After that, the Monitor memory cleared. As another function the synchronization station included in the monitor, rechargeable Charge energy sources.

The data transfer to the control center can be done by e.g. B. at night the charging and synchronization station from the central computer is called or she calls the central computer, after which they request the stored data transfers. This can also be done in the charging and synchronization station existing timers with the time base of the central computer to be matched. The connection the center is either via its own modem built or via the modem of an existing one Facility for researching audience behavior. The second option is to load the disk and Send the synchronization station to the control center. Finally, the monitors themselves can also go to the head office be sent in, again the built-in timer be synchronized with the time base of the control center can.

The monitor can be connected to the current in various ways Conditions are adjusted. In particular, the different Processing procedures using only one processor be performed. With a recording time of just one Seconds per minute, he has 59 seconds to complete the Transformation, compression and encryption perform. Carrying out all of these operations a processor also has the advantage that only by exchanging the program that controls the processor, a change in the overall functionality is possible. Z. B. the encryptor or its key can be replaced the compression can be switched on and off and other transformation methods can be used become.

The filter 2 can also be digital and then be arranged behind the analog-digital converter. Analogous can also filter from one processor to digital Kind of be done. The order of the functional elements can also be chosen differently overall.

The synchronization of the time base 9 can therefore become obsolete that the time base 9 is a receiver for a time normal signal, z. B. DCF-77, which also includes the program samplers is used as the time standard.

A problem with the purely acoustic recording of the audio samples is a possibly high ambient noise level. A possible solution is that on the speakers so-called mini spies are attached, which are the structure-borne noise of the respective speaker and directly on radiate the monitors, e.g. B. by means of radio signals, infrared or ultrasound. The monitor can also be connected directly to the Speaker or headphone output z. B. a Walkman connected become. A monitor can also be stationary on a Hi-Fi stereo system attached using an adapter be the input of the people listening allows. The monitor could also be equipped with a button that allows the wearer to disable the monitor, z. B. during a confidential conversation.

A preferred embodiment will now be described with reference to FIG. 2. Here, the monitor, that is, the hearing sampler that the listener is carrying, is integrated in a watch, preferably a wristwatch. The microphone 1 has a high to very high sensitivity for the sound waves 11 within a frequency range of approx. 200 s ^-1 to 3000 s ^-1 , but a low sensitivity outside this range. As a result, the microphone 1 performs pre-filtering. The branch 13, which is used for feeding signals instead of or in addition to being recorded via the microphone 1, is discussed below.

From the microphone 1, the already bandwidth-limited (approx. 200-3000 s ^-1 ) signal 14 arrives at an amplifier and bandpass 15, which raises the signal for the subsequent A / D converter 3 to the necessary level and the bandwidth limitation with the desired sharpness causes. The output signal 18 of the amplifier 15 reaches the A / D converter 3, which converts it into a digitized form 20. The conversion takes place with a sampling rate of 6000 s ^-1 and a resolution of 8 bits (= 1 byte) per sample. Switching through the output signal during the sampling interval is carried out by switch 22. Since the sampling interval lasts one second, 6000 values (= 6000 bytes) reach the buffer memory 4 in the meantime. Switches 22 and A / D converter 3 are controlled by the timer 9, which can be coupled to the time display of the watch or works separately from it. whereby the timer 9 supplies the A / D converter 3 with the sampling rate signal 24 of 6000 s ^-1 and the switch 22 with the switching signal 25 with a duration of 1 s per minute.

The data 29 from the Fourier transform unit become the buffer 4 5 read out. The Fourier transform unit processes 200ms sections of the one-second Audio samples so that as a result per sampling interval five Fourier coefficient sets 30 arise, which initially are stored in a buffer 32.

From this, the Fourier coefficients 34 are fetched from the data compressor 6 and reduced in scope without loss of information by one of the common compression methods, such as Huffmann coding, Lempel-Ziv-Welch method, etc. Compressions of up to 2/5 of the initial data volume can be achieved here, or even more if more powerful methods are known and used. Experience has shown that around 100 bytes of compressed data are generated per sampling interval, ie per minute. The compressed Fourier coefficient data sets 37 are stored in a non-volatile memory 8, e.g. B. a flash EPROM, with a capacity of z. B. 1 MB (= 2 ²⁰ bytes) saved. With this capacity, with a data flow of 100 bytes per minute, an uninterrupted wearing time of the watch from a few days to reading out the memory can be achieved. As the storage capacity continues to increase as technology continues, this time will increase.

At least the Fourier transformer unit 5 and the data compressor 6 are under the control of a processor implemented by a respective program. At the same time, the processor can still, if necessary, the above Take over the mentioned encryption.

Reading the data from and deleting the EPROM 8 takes place in the loading and synchronization station 39, in the the watch containing the monitor can be inserted. The energy and data transmission takes place without contact via electromagnetic coupling, which prevents the watch from opening and loading and reading only a small amount of effort requires instruction from the operator, i.e. without further ado can also be carried out by the test person. The monitor in the watch indicates contact with the charging station 39 the functional elements readout control 40 and Reset and erase control 41 for reading out and erasing of the memory 8, a timer synchronization unit 42 for synchronization of the monitor timer 9 and a battery charger 43 on the monitor's battery contains and recharging this battery serves. The data transmission is preferably serial.

The synchronization of clock 9 is necessary because of the 200 ms divisions of the 1 second samples exactly in time with the Samples in the transmitter must be correlated, which also with problems with a quartz time base for days can. To compensate for one of the most important influencing factors, the temperature, the temperature dependence becomes for each monitor of the timer 9 determined and stored. With the help of a timer 9, d. H. especially with the quartz, coupled temperature sensor contained therein the time deviation can be determined by the influence of temperature and corrected, giving an accuracy of ± 200 ms Gait errors can be achieved per week.

Other possible additional devices are personal identification 45, an "on" detector 46, an attention button 48 or the like to enter that just with increased Attention is listened to, etc. Personal identification 45 is fixed as the identifier of the carrier. Conceivable However, it is also necessary to provide several identifiers under which are selected by the controls of the watch can.

The "applied" detector 46 is used to automatically determine whether the clock, d. H. the monitor, from the test person is created and thus the audio samples also the listening impression corresponds to the person. As a secondary function, if not created Watch the hearing monitoring can also be turned off, for. B. at night. The detector 46 can be inductive or capacitive Be executed, for example, on the closeness to the body of the test person or the state of the Bracelets (open / closed) appeals.

The attention button 47 is used to increase phases Have the examiner manually mark attention can.

The comparative hearing samples, the transmitter side, z. B. in the studio, be included, functionally the same assembled monitor processed and saved. Instead of However, the signal is sent via the branch via microphone 1 13 fed directly at the input of the amplifier 15. The Final storage takes place on a data medium of large capacity as usual in computer technology, e.g. B. based of magnetic tapes. The portable, automatic operation necessary functions like that Interface units to the charging and synchronization station, attention button, "Applied" sensor etc.

The invention can also be used to determine subscriber behavior for others that have an acoustic component Use broadcast types, such as B. television.

Claims (16)

1. Method for the identification of a hearing impression perceived by a listener, preferably of a radio or television program, characterised in that hearing samples are recorded in the environment of the listener and stored, and in that the recording of the hearing samples is effected at predetermined times and/or information concerning the recording time is stored together with the hearing sample, the recorded signal being digitised, a compression being effected to obtain a data rate of 100 Bytes/Min. at the most, and the compressed signal being stored in a non-volatile storage device (8) having no mechanically movable components that 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. Method according to claim 1, characterised in that radio programs perceived by a listener are determined.
3. Method according to one of claims 1 or 2, characterised in that hearing samples are determined by recording acoustic signals (11) with or without ambient noise at predetermined times during a recording interval, the recording interval being substantially shorter than the time between two recording times, and the recording duration being comprised between 0.1 and 10 s, preferably between 0.5 and 2 s.
4. Method according to claim 3, characterised in that 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.
5. Method according to one of claims 1 to 4, characterised in that a frequency band from about 100 s^-1 to 4000 s^-1, preferably from about 300 s^-1 to 3000 s^-1, or a partial range thereof, is filtered out from the hearing sample.
6. Method according to any one of claims 1 to 5, characterised in that the recorded signal is subjected to a transformation, more particularly to a Fourier transformation, a Fast Fourier transformation, or a Laplace transformation.
7. Method according to one of claims 1 to 6, characterised in that the storage is effected in non-volatile or battery-buffered semiconductor memories, more particularly electrically erasable permanent memories.
8. Method according to one of claims 1 to 7, characterised in that an encoding is applied to the digitised signal prior to storage, more particularly an irreversible encoding.
9. Device for carrying out the method according to one of claims 1 to 8, characterised in that it comprises at least the following components that are connected to each other in the indicated order by their respective outputs and inputs: a microphone (1); at least one component (1, 15) for filtering out a frequency band; an analog to digital converter (2); a processing unit (5, 6, 7; 5, 32, 6) for the digitised data, particularly including a processor capable of program controlled processing, the processing unit applying at least one compression method to the digitised data such that the digitised data are available at its output at a rate of 100 Bytes/Min. at the most, and a non-volatile memory (8) for the digitised, compressed data, the memory (8) having no mechanically movable components that are essential for the storage operation and preferably being a non-volatile or battery-buffered semiconductor memory, in that it includes a timing unit (9) for determining the time of the hearing samples, and in that the device is designed so small and light that it may be discreetly carried by a person, more particularly in the form of a wristwatch, a clip, or a cheque card.
10. Device according to claim 9, characterised in that the non-volatile memory is an electrically erasable permanent semiconductor memory, preferably of the FLASH EPROM type.
11. Device according to claim 9 or 10, characterised in that the timing unit (9) comprises a real time base capable of being adjusted to a reference time base by means of a synchronising unit (39) and that the real time base is provided with at least one correction unit for correcting time deviations caused by temperature variations, the correction unit responding to the temperature in the vicinity of the time base.
12. Device according to one of claims 9 to 11, characterised in that the timing unit (9) comprises a receiver and decoder for standard time signals.
13. Device according to one of claims 9 to 12, characterised in that the device is capable of being carried by the test person and comprises a capacitive or inductive sensor (46) for generating a signal indicating that it is being carried by the person.
14. Installation comprising a device according to one of claims 9 to 12, characterised in that the installation comprises a second microphone, more particularly an impact sound microphone fastened to a speaker of a radio or television receiver, in that a transmitter is connected to the second microphone for wireless emission of the signal recorded by the second microphone, and in that the device comprises a receiver for this signal.
15. Method for determining the behaviour of listeners or viewers, characterised in that hearing samples are collected according to one of claims 1 to 8, in that program samples of at least one radio or television program that temporally overlaps at least partially with the hearing samples are generated and stored, the hearing samples and the program samples being subjected to the same processing steps between their recording and storage, and in that temporally corresponding hearing samples and program samples are correlated at a later time, a positive correlation result indicating coincidence between the program captured by the hearing samples and that captured by the program samples.
16. Method according to claim 15, characterised in that the program samples are subjected prior to their storage to a first series of processing steps, and between their readout from the storage medium and the correlation to further processing steps, more particularly to an encoding, in order to condition the program samples for the correlation with the hearing samples.

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