WO2013171255A1

WO2013171255A1 - Head-tracking headset and device

Info

Publication number: WO2013171255A1
Application number: PCT/EP2013/060018
Authority: WO
Inventors: Christian Hoene; Patrick SCHREINER
Original assignee: Eberhard Karls Universität Tübingen
Priority date: 2012-05-15
Filing date: 2013-05-15
Publication date: 2013-11-21
Also published as: DE102012208118A1

Abstract

A head-tracking headset (10) has: a first connection (9), by means of which a first signal (S1) is sent, a second connection (5), by means of which a second signal (S2) is received, which contains a stereophonic sound signal (RS), at least one sound transducer (4), which converts the stereophonic sound signal into a sound signal, a microphone (3) for producing a microphone signal (MS), sensors (2) for determining a head pose or a head orientation, wherein the sensors produce digital sensor data in accordance with the head pose or the head orientation, a modulator (6), which is designed to modulate a sensor data carrier signal with the digital sensor data, and a superposing circuit (7), which is designed to superpose, in particular to add, the microphone signal and the sensor data carrier signal modulated with the digital sensor data to form the first signal.

Description

Headtracking headset and device

The invention relates to a head-tracking headset and an associated remote station in the form of a device.

A headset is a combination of headphones and microphone. For example, headsets can be connected to personal computers (PCs), notebooks, smartphones, and cell phones (collectively referred to as "computers" or "devices") to listen to, talk, or play music, for example.

Headsets are available in mono and stereo versions. A mono headset only supports one acoustic transmission channel. A stereo headset has two channels, one for the right and one for the left ear.

Headsets can be connected to computers via cable or wireless in a variety of ways. For PCs and notebooks, two three-pin 3.5mm phone plugs are usually used to connect the headset. The jack plugs typically have the colors green and red. Green is used to control the headphones, whereby analogue acoustic signals for the headphones are transmitted via the green connection.

Red is intended for the connection of a (mono) microphone, which also reproduces the acoustic signals in analog form. Often, the red microphone port of a computer also provides a power supply needed by some microphone technologies for operation. Mobile phones often do not have two separate phone jacks, but use different male-female combinations. Current smartphones, for example, have a four-pin phone plug that serves as both a headphone jack and a microphone jack.

The term head tracking means "head tracking". Head tracking typically determines the location and orientation of the head. Here, up to six degrees of freedom (DOF) can be determined. X, Y and Z coordinates can be determined for the location and the roll, pitch and yaw angles (English pitch, yaw, roll) for orientation. These six degrees of freedom are also summarized under the term (head) pose. Technically, there are different ways to determine the pose. For orientation, the measurement of the magnetic field (compass), gravitational acceleration (as in the case of the solder) and the rotational acceleration (as with the gyroscope) are suitable. The position can be determined for example by means of GPS or indoors by means of ultrasound, cameras, radio waves, etc.

Headtracking headsets are often used in conjunction with so-called surround sound applications. Such surround sound applications take advantage of the fact that humans can naturally hear in space. The human being not only records the sound waves (and their meaning), but also can estimate from which direction the sound waves come and how far away the sound source is. This ability is called spatial hearing. To realistically reproduce surround sound using a surround sound application, stereo headphones can be used. The acoustic signal to be reproduced is recorded by means of a so-called head Related-Transfer-Function (HRTF) filtered, which enhances the impression of space. The HRTF modifies the sound waves depending on the direction they arrive at the head of the listener. In other words, the sound has a different sound when it arrives at the listener from the front, back, left, right, up, or down.

In addition to HRTF, head tracking is also helpful to increase localization accuracy. In this case, a head pose or head orientation is recorded and, among other things, the HRTF is automatically adjusted depending on head position or head orientation, because after a head movement the sound also comes from a different direction.

To create a realistic spatial impression, head-tracking headsets are therefore well suited.

The invention has for its object to provide a head-tracking headset, a device and a system that are simple and inexpensive to implement and in particular require no change in conventional connections or interfaces in the device.

The invention achieves this object by a headtracking headset according to claim 1, a device, i. the corresponding remote site, such as a PC, a notebook, a smartphone, etc., according to claim 12 and a system according to claim 16.

The headtracking headset has a first port through which a first signal is transmitted from the headtracking headset, and a second port through which a second signal is received from the device that includes a surround sound signal that is, for example, head-based. or head pose dependent is generated by an associated surround sound application. The first terminal may correspond to a conventional microphone terminal, which is conventionally coded by means of the color red.

The second connection may, for example, correspond to a conventional stereo headphone jack or a jack or a jack plug, which is conventionally coded by means of the color green.

Alternatively, the first and the second terminal may be part of a conventional four-pole jack or a corresponding four-pin phone jack, which serves as both headphone and as a microphone connection. The first port then corresponds, for example, to the microphone portion of the four-pole jack plug or the four-pin jack socket, and the second port corresponds, for example, to the headphone portion of the four-pin jack plug or the four-pin jack socket. For example, each of the first and second terminals has a first connection point or a first connection terminal for a reference potential, wherein the reference potential of the first and the second connection can be identical, and each have a second connection point or a second connection terminal for one associated signal potential, so that the first and the second signal is transmitted as a potential difference between the respective first and second terminal.

The headtracking headset further has at least one, for example exactly two, conventional sound transducers 4, which convert or convert the surround sound signal into a sound signal. The transducers form the headphones of the headtracking headset.

The headtracking headset further includes a conventional microphone for generating a microphone signal. The head tracking headset further comprises one or more conventional sensors for determining a head orientation or head pose, the sensors generating head sensor or head orientation dependent digital sensor data. The sensors can detect the complete position, ie position and orientation of the head. However, the sensors can also detect only the head orientation, for example in the form of a relative rotation of the head, since surround sound can generally be simulated sufficiently well if only the orientation is detected. Typical sensors that can be used for orientation determination are based on Micro-Electro-Mechanical Systems (MEMS) technology to detect acceleration, spin acceleration, and / or magnetic fields. To determine the position, optical sensors (cameras), RF-based field or transit time measurements or ultrasonic sensors can be used. Typically, the sensors are extended by a CPU to condition the sensor data, ie to generate the associated digital sensor data from analog sensor sizes.

The head tracking headset further includes a modulator configured to modulate a sensor data carrier signal with the digital sensor data. The sensor data carrier signal can, for example, be amplitude, phase or frequency modulated.

The head tracking headset further comprises an overlay circuit which is designed to superimpose, in particular to add, the microphone signal and the sensor data carrier signal modulated with the digital sensor data to the first signal.

The sensor data carrier signal may have a carrier frequency, which is for example about 22 kHz and which is greater than an upper microphone signal cutoff frequency, which is for example about 18 kHz. The superposition circuit may be designed to limit the microphone signal in the frequency domain to the upper microphone signal cutoff frequency. For this purpose, corresponding low-pass or bandpass filters may be provided in the superposition circuit.

The second signal may include a control signal in addition to the surround sound signal, wherein the control signal is generated by modulating a control data carrier signal with digital control data in the remote station, wherein the control data carrier signal has a carrier frequency which is approximately 22kHz, for example is and which is greater than an upper Raumklangsignal cutoff frequency, which is for example about 18kHz, wherein the surround sound signal and the modulated with the digital control data control data carrier signal for generating the second signal superimposed, in particular added, are.

The headtracking headset may further comprise: a filter, comprising for example a first and a second bandpass filter unit, which or the second signal in the frequency domain in a first signal portion corresponding to the second signal in a frequency range up to the Raumklangsignal cutoff frequency and which decomposes the surround sound signal and decomposes a second signal component corresponding to the second signal in a frequency range above the surround signal threshold frequency, and a demodulator which demodulates the second signal component of the second signal to demodulate the control data.

Depending on the control data, for example, operating parameters of the head tracking headset can be set. For example, the control data may be used to transmit control information from the device to the head-tracking headset, for example to turn the sensors off or on, to change a capture rate, to perform firmware updates, and so forth. The headtracking headset may include an energy harvesting circuit configured to generate operating power for the headtracking headset and / or an energy store of the headtracking headset from the second signal.

The energy recovery circuit may be configured to generate the operating energy from a signal component of the second signal, which is in a frequency range above the Raumklangsignal- cutoff frequency, for example in a frequency range above about 22kHz.

The second signal can have a control signal and a signal for energy transmission as superposed signal components in addition to the surround sound signal. The surround sound signal may include a variable surround signal level, the control signal may include a variable control signal level, and the energy transfer signal may include an adjustable power signal level. The surround signal level may depend on the control signal level and / or the power signal level. The energy signal level may depend on the surround signal level and / or the control signal level. The control signal level may depend on the surround signal level and / or the power signal level.

The second signal transmits in this case both the surround sound signal, the control signals and the power transmission signal. However, the maximum level of the second signal may be limited and override should be avoided. To ensure this, all three signals could be limited, for example, to one third of a maximum allowable level of the second signal. However, this would have the disadvantage that the surround sound signal level to one third the maximum level would be limited. According to the invention, the levels or volume levels of the three individual signals are regulated as a function of the level of a signal of the other two signals or the level of the two other signals. If, for example, an energy store of the headset is loaded and no control data are to be transmitted, the surround sound signal can be transmitted at full volume since the other two signals can be switched off. If, however, the power supply is not guaranteed, the level of the power supply signal must be increased at the expense of the other two signals. Conversely, if just high-level surround sound signals are being transmitted, the level or amplitude of the other two signals should be reduced. If, on the other hand, only a quiet room sound signal is transmitted, the other two signals can be amplified. It is also possible to delay the transmission of the signals in time, if just a signal requires a high level or a high amplitude. For example, the control signal can be delayed in time if the surround sound signal is currently noisy.

The headtracking headset may further comprise a sensor data compression unit configured to compress the digital sensor data before it is modulated with the sensor data carrier signal. In this case, the (digital) sensor data is compressed before it is transmitted, resulting in a higher data transfer rate and better channel utilization. In principle, similar methods can be used in this case as well as in the compression of speech signals. An example of such a method is "Adaptive Differential Pulse Code Modulation." One encoder for each roll pitch yaw angle could be used to reduce the data rate, for example, a faster ADPCM can be used. Transfer mode and a slower, but more accurate and absolute PCM mode are switched. The sensors can be designed to determine further measured variables, such as, for example, temperature, heart rate, magnetic field and / or sound, wherein corresponding digital sensor data are also generated for these measured variables, which are then modulated and transmitted with the sensor data carrier signal. Not only can data be transmitted to the head pose, but also other sensor information or sensor data, such as temperature, heart rate, pressure, body conductance, keystrokes, proximity sensors (to determine if and how the headset is attached), magnetic field (for a Compass function), pedometer, gyroscopes, sound signals (especially low frequencies), optical signals (for example, the positions of bright light sources such as Wiimode), etc. The device for receiving the first signal from a headtracking headset mentioned above and sending the second signal to the headtracking headset, the device in the form of a personal computer, a notebook, a smartphone, etc., has a first port, via which the first signal is received by the headtracking headset, the first port of the device corresponds to the first port of the headtracking headset, and a second port via which the second signal is sent to the headtracking headset, the second port of the device corresponding to the second port of the headtracking headset.

The device further comprises a filter, for example comprising a first and a second bandpass filter unit which decomposes the first signal in the frequency domain into a first signal component which corresponds to the first signal in a frequency range up to the microphone signal cutoff frequency and a second signal component or decompose, which corresponds to the first signal in a frequency range above the microphone signal cutoff frequency. The apparatus further includes a demodulator that demodulates the second signal portion to demodulate the sensor data. The device may include a surround sound unit that generates the surround sound signal in response to the demodulated sensor data.

The device may include a modulator configured to modulate the control data carrier signal with the digital control data, and an overlay circuit configured to convert the surround signal and the control data carrier signal modulated with the digital control data to the second Signal to superimpose, in particular to add. The device may comprise an energy signal generation unit which is designed to generate an energy signal which has exclusively frequencies in a frequency range above the surround signal threshold frequency, for example above about 22 kHz, wherein the overlay circuit is further adapted to the surround sound signal associated with the digital control data modulated control data carrier signal and the energy signal to the second signal to superimpose, in particular to add.

The system includes a headtracking headset and a device.

The invention will be described below with reference to the drawing. This shows schematically:

Fig. 1 is a headtracking headset and associated device.

Fig. 1 shows a system comprising a head-tracking headset 1 and an associated device 8 in the form of a so-called smartphone. The headtracking headset 1 and the device 8 are electrically connected to each other by means of a single conventional cable with a four-pole jack plug or by means of two conventional cables, each with three-pole jacks, the four-pin jack plug into a corresponding socket of the headtracking headset (not shown) 1 can be plugged. When the connection is established, a first connection 9 of the head-tracking headset 1, which conventionally serves as a microphone connection, is connected to a corresponding first connection 15 of the device 8 and a second connection 5 of the headtracking headset 1, which conventionally serves as a headphone connection , is connected to a corresponding second terminal 16 of the device 1. With regard to a possible signal assignment of the cable or jack connector, reference is also made to the relevant specialist literature.

A first signal S1 is sent to the device 8 via the first connection 9 of the headtracking headset 1, and a second signal S2 from the device 8, which contains a conventional surround sound signal RS, is received via the second connection 5.

The headtracking headset 1 has two sound transducers 4 (only a single sound transducer 4 is shown by way of example), which form a headset, with the sound transducers 4 conventionally converting the (stereo) surround sound signal RS into an audible sound signal.

Furthermore, a microphone 3 is conventionally provided for generating a microphone signal MS. Sensors 2 with integrated signal processing are used to determine a head orientation, wherein the sensors 2 generate digital sensor data depending on the head orientation. A modulator 6 of the headtracking headset 1 is designed to modulate a sensor data carrier signal with the digital sensor data, an overlay circuit 7 of the headtracking headset 1 being designed, the microphone signal MS and the sensor data modulated with the digital sensor data. Suppose carrier signal to the first signal S1 to superimpose, in particular to add.

The sensor data carrier signal has a carrier frequency that is greater than an upper microphone signal cutoff frequency.

The superposition circuit 9 is designed to limit the microphone signal in the frequency domain to the upper microphone signal cutoff frequency. For this purpose, the overlay circuit 9 comprises one or more filter units with suitably selected edge frequencies.

By means of the sensors 2, the head orientation is conventionally determined. The sensor data carrier signal is modulated with the corresponding sensor data (if necessary previously converted into a corresponding analog signal) and combined with the analog microphone signal MS using output filters not shown in detail in the superposition circuit 9. The combined signals are thus transmitted to the device 1 as the first signal S1. To separate the signals combined in the first signal S1, the device 8 has a filter 10 which divides the first signal S1 in the frequency domain into a first signal component which corresponds to the first signal in a frequency range up to the microphone signal cutoff frequency, and a second signal component. which corresponds to the first signal in a frequency range above the microphone signal cutoff frequency. The first signal component corresponds to the microphone signal MS and can be suitably processed further.

To recover the sensor data, the receiver 8 has a demodulator 11, which demodulates the second signal component in order to demodulate the sensor data.

A surround unit 12 generates the surround sound signal RS in response to the sensor data.

To transmit control data to the headtracking headset 1, the device 8 has a modulator 17, which is designed to modulate a control data carrier signal with the digital control data. The control data carrier signal can, for example, be amplitude, phase or frequency modulated. The control data carrier signal has a carrier frequency which is greater than an upper Raumklangsignal- cutoff frequency.

Downstream of the modulator 17 is an overlay circuit 18, which is designed to superimpose, in particular to add, the spatial sound signal and the control data carrier signal modulated with the digital control data to the second signal S2.

For extracting this control data from the second signal S2, the headtracking headset has a filter 12, which the second signal in the frequency domain in a first signal component corresponding to the second signal in a frequency range up to the Raumklangsignal cutoff frequency and which forms the surround sound signal, and decomposes a second signal component which corresponds to the second signal in a frequency range above the surround signal frequency limit frequency. A demodulator 13 demodulates the second signal portion of the second signal S2 to demodulate the control data.

By means of the control data operating parameters of the headtracking headset are adjustable.

To supply the headtracking headset 1 with energy, the device 8 has an energy signal generation unit, not shown, which is designed to generate an energy signal, for example in the form of a high-frequency sinusoidal voltage signal, which exclusively contains frequencies in a frequency range above the surround sound signal cutoff frequency wherein the superposition circuit 18 is further configured to add, in particular, the surround sound signal, the control data carrier signal modulated with the digital control data, and the energy signal superimposed on the second signal.

Corresponding to the energy signal generating unit of the device 1, the headtracking headset 1 has an energy recovery circuit 14, which is designed to generate operating energy for the headtracking headset 1 and / or an energy storage of the headtracking headset 1, not shown, from the first signal S1. The power generation circuit 14 is configured to generate the operating power from a signal portion of the second signal S2, i. the energy signal, which is in a frequency range above the carrier frequency of the control data carrier signal.

According to the invention, the analogue input signal S2 of the headtracking headset 1 can be separated into a surround sound signal RS and a control signal by means of two filter units, which can be provided in the filter 12. While the surround sound signal RS directly to the Sound transducer 4 and the headphones is passed, the control signal is demodulated and processed appropriately.

By means of the sensors 2, a head orientation or head pose is determined. The correspondingly generated sensor data are converted into an analog signal, modulated and combined with the analog microphone signal MS by means of suitable output filter units, which may be contained in the superposition circuit 7. The combined signals are thus transmitted as the first signal S1 to the device 8.

If the power supply of the headtracking headset 1 is to be realized by an energy harvesting circuit or energy harvesting circuit 14, the filter 12 may comprise a high-pass filter unit which extracts a high-frequency range of the second signal S2. The frequency range provided for the energy harvesting circuit 14 can be very narrowband.

If temporarily no relevant audio data (e.g., silence) is transmitted to the headtracking headset 1, it is possible to modulate only one high frequency signal to ensure the power supply.

In addition, the power supply of the head tracking headset 1 can be ensured by a battery, an accumulator or by piezoelectric or thermoelectric generators.

The filter units possibly provided in the superposition circuit 7 can be adapted to corresponding filter units of the filter 10 in the apparatus, ie the microphone signal MS and the sensor data signal are to be superimposed in the frequency domain. The structure of the headtracking headset 1 is essentially independent of the type of device 1 used. In other words, regardless of the type of device used, identical filter configurations can be used.

In the device 1, low frequencies and DC components can be filtered out, for example, by means of an upstream capacitor at the first signal S1. The received and properly filtered signal can be converted to a digital signal and then split into audio data and modulated sensor data.

For example, the audio data or microphone data is routed directly to the processing application. In contrast, the sensor data is demodulated and then also transmitted to a processing application, such as a surround sound application.

Furthermore, a signal for controlling the sensors 2 is generated in the device 1, which subsequently serves to modulate a carrier signal. The audio stream to be played out in the form of the surround sound signal RS and the control signal are combined and transmitted to the headtracking headset 1. The filter units possibly provided in the filter 12 should be adapted to the corresponding filter units in the device 1.

Via the individual connection 9 of the headtracking headset 1, both audio signals and sensor data are transmitted, which are modulated onto an associated carrier signal. The sensors 2 are integrated into the headtracking headset 1 to determine the head orientation or head pose. The sensor data can be used for any application (including surround sound calculations) on any audio-processing devices (eg PC, smartphone, tablet, etc.) can be used.

Claims

Patent claims

1. Head tracking headset (1), comprising:

a first connection (9), via which a first signal (S1) is sent,

a second connection (5), via which a second signal (S2) is received, which contains a surround sound signal (RS), at least one sound transducer (4), which converts the surround sound signal (RS) into a sound signal,

at least one microphone (3) for generating a microphone signal (MS),

Sensors (2) for determining a head pose or a head orientation, the sensors (2) generating digital sensor data depending on the head pose or head orientation, a modulator (6) which is designed to modulate a sensor data carrier signal with the digital sensor data, and

a superposition circuit (7), which is designed to superimpose, in particular add, the microphone signal (MS) and the sensor data carrier signal modulated with the digital sensor data to the first signal (S1).

2. Head tracking headset (1) according to claim 1, characterized in that the sensor data carrier signal has a carrier frequency that is greater than an upper microphone signal limit frequency.

3. Head tracking headset (1) according to claim 2, characterized in that the superposition circuit (7) is designed to limit the microphone signal (MS) in the frequency range to the upper microphone signal limit frequency.

4. Head tracking headset (1) according to one of the preceding claims, characterized in that

the second signal (S2) contains a control signal in addition to the surround sound signal (RS), the control signal being generated by modulating a control data carrier signal with digital control data, the control data carrier signal having a carrier frequency that is greater than an upper surround sound signal -Cut-off frequency, wherein the surround sound signal (RS) and the control data carrier signal modulated with the digital control data are superimposed, in particular added, to generate the second signal (S2), the head tracking headset (1) further comprising:

a filter (12) which splits the second signal (S2) in the frequency range into a first signal component which corresponds to the second signal (S2) in a frequency range up to the surround sound signal limit frequency and which forms the surround sound signal (RS), and a second signal component , which corresponds to the second signal (S2) in a frequency range above the surround sound signal cutoff frequency, and

a demodulator (13) which demodulates the second signal component of the second signal (S2) in order to demodulate the control data.

5. Head tracking headset (1) according to claim 4, characterized in that operating parameters of the head tracking headset (1) can be adjusted depending on the control data.

6. Head tracking headset (1) according to one of the preceding claims, characterized by

an energy generation circuit (14) which is designed to generate operating energy for the head tracking headset (1) and/or to generate an energy storage of the head tracking headset (1) from the second signal.

7. Head tracking headset (1) according to claim 6, characterized in that the energy generation circuit (14) is designed to generate the operating energy from a signal component of the second signal (S2) which is in a frequency range above the surround sound signal limit frequency.

8. Head tracking headset (1) according to one of the preceding claims, characterized in that the second signal (S2) has, in addition to the surround sound signal (RS), a control signal and a signal for energy transmission, the surround sound signal (RS) having an adjustable surround sound signal level , the control signal has an adjustable control signal level and the signal for energy transmission has an adjustable energy signal level, wherein the surround sound signal level depends on the control signal level and / or the energy signal level, and / or the energy signal level depends on the surround sound signal level and / or on the control signal level, and / or control signal level depends on the surround sound signal level and/or the energy signal level.

9. Head tracking headset (1) according to one of the preceding claims, characterized in that the second signal (S2) has, in addition to the surround sound signal (RS), a control signal and a signal for energy transmission, the surround sound signal (RS) having a surround sound signal level, the control signal has a control signal level and the signal for energy transmission has an energy signal level, the surround sound signal (RS), the control signal and / or the signal for energy transmission depending on the surround sound signal level, the control signal level and/or the energy signal level is/are transmitted with a time delay.

10. Head tracking headset (1) according to one of the preceding claims, characterized by a sensor data compression unit which is designed to compress the digital sensor data before they are modulated with the sensor data carrier signal.

1 1. Head tracking headset (1) according to one of the preceding claims, characterized in that the sensors (2) are designed to determine further measured variables, such as temperature, heart rate, magnetic field and / or sound.

12. Device (8) for receiving the first signal (S1) from a head tracking headset (1) according to one of the preceding claims, comprising:

a first connection (15), via which the first signal (S1) is received by the head tracking headset,

a second connection (16), via which the second signal (S2) is sent to the head tracking headset (1),

a filter (10) which breaks down the first signal (S1) in the frequency range into a first signal component which corresponds to the first signal (S1) in a frequency range up to the microphone signal limit frequency, and a second signal component which corresponds to the first signal (S1). in a frequency range above the microphone signal limit frequency, and a demodulator (1 1 ), which demodulates the second signal component in order to demodulate the sensor data.

Device (8) according to claim 12, characterized by a surround sound unit (12) which generates the surround sound signal (RS) as a function of the sensor data.

14. Device (8) according to claim 12 or 13, characterized by

a modulator (17) which is designed to modulate the control data carrier signal with the digital control data, and

a superposition circuit (18) which is designed to superimpose, in particular add, the surround sound signal (RS) and the control data carrier signal modulated with the digital control data to the second signal (S2).

15. Device (8) according to one of claims 12 to 14, characterized by an energy signal generation unit which is designed to generate an energy signal which exclusively has frequencies in a frequency range above the surround sound signal limit frequency, the superposition circuit (18) furthermore is designed to superimpose, in particular add, the surround sound signal (RS), the control data carrier signal modulated with the digital control data and the energy signal to the second signal.

System comprising:

a head tracking headset (1) according to one of claims 1 b 1 1 and

a device (8) according to one of claims 12 to 15.