Patent Application
20070127750
The invention relates to a hearing system, which comprises at least one hearing device, and which is capable of generating sounds or signals to be perceived by a user of the hearing system. The hearing device can be a hearing aid, worn in or near the ear or implanted, a headphone, an earphone, a hearing protection device, a communication device or the like.
From DE 10 2004 035 046 A1, binaural hearing systems are known, which provide for “virtual sound sources” in the sense that system-generated sounds can be perceived by a user of the system as if they were generated in certain locations near the user. The system-generated sounds are processed with HRTF (head-related transfer functions) for each ear, so that the user's left and right ears will typically perceive, at slightly different times, slightly different signals, such that the origin of the system-generated sound appears to be in a specific fixed location near the user. The two hearing devices are linked with each other in order to be able to provide a synchronization of the hearing device necessary to achieve a required timing precision for signals played to the user's left and right ears.
From US 2005/0152567 A1, a hearing aid is known, which is capable of generating sounds (device signals) as a function of a hearing aid value, e.g., a battery status. Said device signals can be adjusted in level or type, based on a level of an input signal and a signal shape of the input signal or on a classification of the input signal. In addition, said input signal may be adjusted with respect to the device signal. For example, the level of the device signal is increased when the user is in a loud environment (high input signal) and/or the gain for the input signal is decreased (up to muting) when a device signal is to be output.
A goal of the invention is to create a hearing system and a method of operating a hearing system, that allow for a clear perception of system-generated signals by a user of the system.
One object of the invention is to provide for a hearing system and a method,of operating a hearing system, which provide for a good distinguishability between different system-generated signals.
Another object of the invention is to provide for a hearing system and a method of operating a hearing system, which allow for a clear perception of system-generated signals without a linked pair of hearing devices.
Another object of the invention is to provide for a hearing system without a linked pair of hearing devices and a method of operating such a hearing system, which provide for a good distinguishability between different system-generated signals.
These objects are achieved by hearing systems and by methods according to the patent claims.
In a first aspect of the invention, the hearing system comprises
The corresponding method for operating a hearing system comprising at least one hearing device comprises the steps of
Through this, an improved perception of system-generated signals by a user of the hearing system can be achieved. Said providing of said system-generated audio signals with said spatial information can also be called or considered a providing of said system-generated audio signals with spaciousness
Said system-generated audio signals can be provided with said spatial information in order to achieve the effect, that said spatialized system-generated audio signals, when perceived by the user as output signals, are perceived by the user as signals originating from a virtual location, wherein said virtual location is chosen in dependence of said localization information.
The spatialization of the system-generated signals gives the user the impression that the signals perceived by him, when said spatialized system-generated audio signals are converted in said output converter into output signals, originate from a virtual location. And that virtual location is chosen in dependence of said localization information.
A virtual location is defined by an apparent distance from the user and/or an apparent azimuthal angle and/or an apparent polar angle, where the signals are apparently coming from. It may comprise apparent room information (information of size and/or shape and/or surfaces and the like of a room inside of which the system-generated sounds are apparently originating in). An apparent distance may result from various effects, among which are damping (reduction of high-frequency components) and reflections.
Said hearing system may comprise one hearing device or two hearing devices, which may be linked (wirelessly or wire-bound) or not-linked. Hearing devices are usually worn in or near a user's ear, or may be implanted. Hearing systems may furthermore comprise remote controls and other accessories.
Typically, said incoming signals are incoming sound (acoustical sound). They may also be of other nature, e.g., electromagnetic waves, e.g., when the hearing system receives frequency modulated radio waves from a speech inside a filled auditorium with the user being inside or outside the auditorium with his hearing system.
Said input unit may comprise one or more input converters, which are typically mechanical-to-electrical converters (e.g., microphones), but converters receiving electromagnetic waves and converting these into audio signals are also possible (e.g., in case of a telephone coil or of a remote frequency modulation receiver or infrared receiver).
Audio signals are usually electrical signals, analogue and/or digital, which describe or represent sound (natural sound or artificially generated sound).
Said output signals are often acoustic signals (sound, sound waves), but may be other signals as well, e.g., in the case of implanted hearing devices. Said output transducers can therefore be electro-to-mechanical converters (loudspeakers) or others, e.g., electrical-to-electrical converters.
Typically, each hearing device comprises one output transducer.
Typically, each hearing device comprises one, possibly two or even more, input transducers.
Typically, at least one or each hearing device comprises a sound generator, which may be realized in form of software.
Said audio analysis unit is typically a software-implemented signal processing algorithm. From the received input signals, information on where in space the input audio signals or a part or different parts of the input signals come from (localization information) is extracted. In case that only one stream of input audio signals is received, e.g., when only one hearing device with only one microphone is comprised in the hearing system, localization information in terms of information on a room (size, shape, surfaces) in which acoustic waves travelled from which the input audio signals are obtained, can be obtained. Mainly, reverberation and echo portions (signals, components) in the input audio signals provide for the necessary information. Furthermore, localization information in terms of distance information is obtainable, at least a maximum distance as obtained from said room information.
If, e.g., two streams of incoming signals are received by the input unit, which, e.g., is the case when the input unit comprises two microphones or when an electrical-electrical converter (of the input unit) receives a stereo signal, localization information may be obtained from a time delay (time-of-reception difference) and/or the loudness difference (level difference) between the two audio streams. In the art, such audio analysis units are also known as localizers and used in conjunction with beam formers. Classifiers, which are also known in the art, may also be used, since they may allow to distinguish between different sound sources if more than one principal sound sources exist.
By analyzing spectral differences (differences in spectral coloration) of the two streams of incoming signals, it is possible to derive directional information. This can be achieved by comparing said spectral coloration with HRTF (head-related transfer functions), which describe such frequency-dependent sound modifications.
From the sketched analyses of the two streams of input audio signals, a rather precise determination of the direction, in which a sound source is located relative to the microphones, is thus enabled, e.g., in terms of an azimuthal and a polar angle with respect to the user's head. In addition, also distance information may be extracted, e.g., as sketched above in conjunction with the analysis of one single stream of input audio signals.
Once said localization information is obtained, it can be decided, where to arrange said virtual location. If, e.g., only one principal sound source is detected, which comprises a lot of reverberation or is located far away, the virtual location could be arranged close to the user.
If the one principal sound source is located to the very right of the user, the virtual location could be arranged to the very left of the user. If, on the other hand, e.g., a principal sound source is located in front of the user, and a major noise source is located far away on the right behind the user, the virtual sound source could be arranged on the left behind and close to the user. In a generally loud environment, the virtual location could be arranged within the user's head.
Said virtual localization processor may be implemented in form of software and generates the reverberation and/or echo signals, and the interaural time differences, the interaural level differences and the different spectral coloration of output signals to be perceived by each of the user's two ears, which are required (and possible) to let the virtual sound source appear in the desired location (with the desired spaciousness). Individually measured and/or averaged or estimated HRTF may be used.
Said system-generated audio signals may be provided with at least one of interaural time differences, interaural level differences, and different spectral coloration of output signals to be perceived by each of the user's two ears as spatial information.
In one embodiment, the kind and/or the amount of said spatial information is chosen in dependence of at least one of a gain model describing hearing preferences of said user and an analysis of said input audio signals. Said analysis of said input audio signals can comprise classifications as they are known in the art. Said gain model takes the user's individual preferences (in case of hearing aids: mostly individual hearing deficiencies) into account.
Typically, the invention can be used in conjunction with acknowledge signals (or other sound messages) as the system-generated audio signals to be perceived by the hearing system user. In particular, said system-generated audio signals may be speech signals.
Acknowledge sounds, also called feedback sounds, are played to the user upon a change in the hearing device's function, e.g., when the user changes the loudness (volume) or another setting or program of one or both hearing devices, or when some other user's manipulation shall be acknowledged, or when the hearing device by itself takes an action, e.g., by making a change, e.g., if, in the case of a hearing aid, the hearing aid chooses, in dependence of the acoustical environment, a different hearing program (frequency-volume settings and the like), or when the hearing device user shall be informed that a hearing device's energy source (battery) is low. Acknowledge sounds can be considered signals that indicate a change in an operational condition of the hearing system.
In a second aspect of the invention, the hearing system comprises
It has been found that it is not always easy for a human being to locate a sound source, in particular, an unmoved sound source. To tell a location difference between two unmoved (fixed) sound sources can be rather difficult. It has been found that it is far easier to clearly identify a movement of a sound source and to distinguish different movements of sound sources. This applies also (and in particular—due to the usually imperfect simulation) to virtual sound sources. Accordingly, as described in said second aspect of the invention, it can be advantageous to associate the (virtual) movement of a spatialized system-generated audio signal with a meaning. E.g., in order to acknowledge that the user has increased the volume of his hearing device, a system-generated sound could virtually rise from about eye-level to well above the user's head. Or, e.g., a change from a hearing program (e.g., number 3) to a hearing program with the next higher number (number 4) could be indicated by a virtual move of the appropriate acknowledge signal (e.g., a speech signal saying “program four”) from left to right. In the case that HRTF (head-related transfer functions) are used as (a part of) said spatial information, this second aspect of the invention is rather valuable, in particular when averaged HRTF are used, since averaged HRTF do not exactly represent the effects that take place at a particular user's head. The determination of individualized HRTF is, on the other hand, rather cumbersome and impractical in a typical fitting environment.
The according method of operating a hearing system comprising at least one hearing device may be considered a method for indicating an operational condition of a hearing system. It comprises the steps of:
In a third aspect of the invention, the hearing system comprises
Although the virtual sound source effect achievable with a binaural hearing system with one hearing device dedicated to each of a user's two ears gives a more realistic impression to the user, it is nevertheless possible to simulate a virtual sound source by means of one single hearing device and with two hearing devices, which are not synchronized with each other. In the case of a single hearing device, spectral coloration and/or reverberation and/or echo signals can be applied as spatial information, and in the case of not-linked hearing devices, in addition, interaural level differences may be applied. In general, that part of HRTF, which does not require a synchronization of hearing devices, may be used in order to simulate a virtual sound source.
Said first, second and third aspects of the invention may be pairwise combined or combined altogether, which can lead to particularly advantageous embodiments. E.g., combining the third aspect with the second aspect (moving virtual sound source) results in an improved distinguishability between different output signals.
Of course, in any case and any aspect of the invention, different output signals (indicative of different parameters) may differ in terms of frequency and spectral content, and in time structure and so on. Through this, the purpose for which signal-generated sounds are generated, can be indicated.
The invention can well be used, when speech signals or more complex sounds are to be generated and presented to the user. The complexity of a sound may manifest in its (large) spectral content, its structure in time or rhythmic or percussive structure. Speech sounds may be used for guiding the user, informing the user and acknowledging events in the hearing system. As opposed to simple “whistle sounds” (typically sine-waves), such more complex sounds can be better localized and more effectively be provided with spatial information. Accordingly, the virtual-sound-source effect is more realistic and therefore of greater use to the user in case of more complex sounds. The simple “whistle sounds” often used as acknowledge sounds are hardly susceptible to a realistic spatialization.
The advantages of the methods correspond to the advantages of corresponding hearing devices.
Further preferred embodiments and advantages emerge from the dependent claims and the figures.
Below, the invention is illustrated in more detail by means of embodiments of the invention and the included drawings. The figures show:
The reference symbols used in the figures and their meaning are summarized in the list of reference symbols. Generally, alike or alike-functioning parts are given the same reference symbols. The described embodiments are meant as examples and shall not confine the invention.
How such localization information 40 can be achieved, is known in the art, at least in the area of hearing devices, in conjunction with localizers, beam formers and classifiers.
The hearing system comprises a sound generator 15, which generates system-generated audio signals 30, typically acknowledge sounds indicating a change in the internal (operational) status of the hearing system 1. These system-generated audio signals 30 are fed to a virtual location processor 16, which provides the system-generated audio signals 30 with spatial information, e.g., by applying appropriate (HRTF) filtering and adding reverberation signals, thus generating spatialized system-generated audio signals 31, so as to create the illusion (to the user) that the system-generated signals originate from a certain place or direction (virtual sound source effect).
The place (virtual location), from where the system-generated signals are apparently perceived by the user, is chosen in dependence of the localization information 40.
From said virtual location processor 16 and also from said DSP 12, audio signals are fed to an output transducer 19, which converts said audio signals into output signals 6 to be perceived by the user, which, in the case shown in
Said DSP 12, audio analysis unit 14, virtual location processor 16 and sound generator 15 may fully or in part be integrated within the same processor and/or within the same software.
The description of
Of course, many different algorithms for determining a virtual location (for a system-generated sound) in dependence of one or more localized sound (or noise) source, are applicable.
In
Said second aspect of the invention is, that a certain system-generated sound does not only occur at a fixed location, but describes a path (or moves), wherein that path indicates a specific operational condition of the hearing system 1, e.g., that an energy supply of the hearing system is unstable. A corresponding path 51 or virtual movement 51 is indicated in
Of course, a hearing system 1 may comprise a control unit and/or a data acquisition unit, by means of which system parameters (related to an operational condition of the hearing system) can be obtained. Appropriate system-generated sounds (and locations and maybe virtual movement paths) may thereupon be chosen.
List of Reference Symbols
