Patent Application
20210272546
The disclosure generally relates to audio systems and in particular to canceling vibration noise in a camera.
In a waterproof camera, a protective membrane may be placed in front of the microphone to prevent water from entering the camera. When the camera moves or external forces are applied to the camera, the membrane may vibrate. The vibrations may be picked up as acoustic noise by the microphone. Additionally, other vibrating components inside the camera may generate additional noise that may reach the microphone. This noise is generally undesirable and may reduce the quality of desired audio signal.
The disclosed embodiments have advantages and features which will be more readily apparent from the detailed description, the appended claims, and the accompanying figures (or drawings). A brief introduction of the figures is below.
FIG. (FIG.) 1 is a block diagram illustrating an example embodiment of an audio sub-system of a camera.
The figures and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed.
Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the disclosed system (or method) for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein.
In an embodiment, a camera includes one or more microphone pairs. A first microphone (e.g., a main microphone) is ported to the outside of the camera and captures the desired external audio signal, but may also capture undesired vibrational noise. A second microphone has a similar structure to the first microphone, but is not ported to the outside of the camera. Instead, the second microphone is ported into an enclosed cavity (e.g., 1-2 cubic centimeters in volume). The second microphone may pick up the same vibration excitation and internal acoustic noise as the first microphone but very little of the desired external acoustic sounds around the camera. The unwanted noise can then be removed by subtracting the second audio signal from the second microphone from the main audio signal from the main microphone.
In a particular embodiment, a camera or other audio capture device includes an audio sub-system that includes structures for enabling noise cancellation. A housing has a microphone port comprising an opening. A first waterproof membrane spans the opening. A printed circuit board is coupled to an interior surface of the housing below the microphone port. The printed circuit board comprises a main microphone opening under the microphone port and a reference microphone opening laterally offset from the microphone port. A main microphone is mounted to a bottom surface of the printed circuit board below the main microphone opening. The main microphone detects ambient audio and generates a main audio signal. A reference microphone is mounted to a top surface of the printed circuit board above the reference microphone opening. The reference microphone captures a reference audio signal. A second waterproof membrane spans the reference microphone opening. A reference structure is configured such that a reference cavity exists below the second waterproof membrane. One or more sealing gaskets isolates the second microphone from the microphone port. A processor (e.g., by subtracting the reference audio signal from the main audio signal).
A reference microphone (Mic 2) 122 is mounted at a different position on the audio PCB 118. For example, the reference microphone 122 may be mounted on a top surface of the audio PCB 118 (e.g., on the side facing the membrane 112) and may also be coupled to an interior surface of the housing 110. The bottom surface of the audio PCB 118 below the reference microphone 122 may attach to a reference structure 124 cantilevered from an interior side surface (e.g., perpendicular to the top surface) of the housing 110. The reference structure 124 may include a waterproof membrane 126 below an opening of the PCB audio 118 below the second microphone 122. The waterproof membrane 126 may be substantially similar in material and thickness to the waterproof membrane 112 such that it produces a similar or vibrational response in response to the same input stimulus.
In an embodiment, the reference structure 124 is attached to the bottom surface of the audio PCB 118 via an elastomer and sealant each having similar structural and material characteristics to the elastomer and sealant used to attach the main microphone 116 to the housing 110. A second acoustical cavity (V2) 128 is formed between the reference microphone 122 and the second membrane 126. This second acoustical cavity 128 may have substantially the same characteristics as the first acoustical cavity 120 (e.g., similar shape, volume, and acoustic characteristics). A reference cavity 130 having a volume V3 is also formed below the membrane 126 and above the cantilever reference structure 124. The volume V3 may be dampened by a dampening element 132.
As can be seen from
The camera 200 can include various indicators, including a display panel 206. The camera 200 can also include buttons 210 configured to allow a user of the camera to interact with the camera, to turn the camera on, and to otherwise configure the operating mode of the camera. The camera 200 can also include one or more audio sub-systems 102 which may each have the structure described above.
In an alternative embodiment, the audio sub-system 102 of
Throughout this specification, some embodiments have used the expression “coupled” along with its derivatives. The term “coupled” as used herein is not necessarily limited to two or more elements being in direct physical or electrical contact. Rather, the term “coupled” may also encompass two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other, or are structured to provide a drainage path between the elements.
Likewise, as used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Finally, as used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs as disclosed from the principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.
This application is a continuation of U.S. patent application Ser. No. 16/718,698, filed Dec. 18, 2019, which is a continuation of U.S. patent application Ser. No. 15/726,320, filed Oct. 5, 2017, now U.S. Pat. No. 10,522,129, which claims the benefit of U.S. Provisional Application No. 62/405,047 filed on Oct. 6, 2016, both of which are incorporated by reference their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62405047 | Oct 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16718698 | Dec 2019 | US |
| Child | 17209092 | US | |
| Parent | 15726320 | Oct 2017 | US |
| Child | 16718698 | US |
