Accelerometer-based exterior sound monitoring for back-up assistance in vehicles

Abstract

Methods and apparatus for accelerometer-based external sound monitoring for back-up assistance in a vehicle are disclosed. An example vehicle includes an accelerometer mounted on the inner surface of a rear window of the vehicle, a rear-view camera, and a processor. The processor identifies a sound source causing vibrations on the rear window, the vibrations being captured by the accelerometer. The processor also classifies the sound and provides an alert based on the category of the sound.

Description

Technical Field

[0001] The present disclosure relates generally to backup assist systems in vehicles, and more particularly to accelerometer-based external sound monitoring for backup assist in vehicles. Background Art

[0002] It is increasingly common for vehicles to be factory-equipped with rear-view cameras and ultrasonic sensors to assist when the vehicle is in reverse or about to reverse. Maintaining these systems can be difficult. For example, dust or snow may obscure the camera or ultrasonic sensor. In addition, especially for ultrasonic sensors, the angle at which the vehicle is currently traveling may cause objects behind the vehicle to be out of sight and therefore undetectable. Summary of the invention

[0003] The appended claims define the present application. This disclosure summarizes aspects of the embodiments and should not be used to limit the claims. Other embodiments are contemplated based on the techniques described herein, as will be apparent to one of ordinary skill in the art having studied the following figures and detailed description, and are intended to fall within the scope of the present application.

[0004] An example vehicle includes an accelerometer mounted on the inner surface of a rear window of the vehicle, a rear view camera, and a processor. The processor identifies a sound source causing vibrations on the rear window, which are captured by the accelerometer. The processor also classifies the sound and provides an alert based on the category of the sound.

[0005] An example method of monitoring an area behind a vehicle includes measuring a signal using an accelerometer mounted on the inner surface of a rear window of the vehicle, the signal being caused by sound waves vibrating the rear window. The method also includes identifying a source of the sound waves and classifying the source. Additionally, the example includes providing an alert based on the classification of the source. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a better understanding of the present invention, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily drawn to scale, and related elements may be omitted, or in some cases the proportions may be exaggerated in order to emphasize and clearly illustrate the novel features described herein. In addition, as is known in the art, the system components may be arranged differently. In addition, in the drawings, the same reference numerals represent corresponding parts in multiple views.

[0007] Figure 1 A vehicle operating in accordance with the teachings of the present disclosure is shown.

[0008] Figure 2 yes Figure 1 Block diagram of the electronic components of a vehicle.

[0009] Figure 3is to use Figure 1 A flow chart of a method for providing back-up assistance using an accelerometer mounted on the rear glass of a vehicle of Figure 2 The electronic components are implemented. DETAILED DESCRIPTION

[0010] While the present invention may be embodied in various forms, some exemplary and non-limiting embodiments are shown in the drawings and will be described below, but it should be understood that this disclosure is considered as examples of the invention and is not intended to limit the invention to the particular embodiments shown.

[0011] Vehicles with rearview cameras and rear ultrasonic sensors assist the driver in detecting obstacles behind the vehicle when the vehicle is in reverse. The image captured by the rearview camera is displayed on a display that is typically built into the center console of the vehicle. Some vehicles include an active safety module that identifies and / or classifies objects based on images captured by the rearview camera and / or measurements from the ultrasonic sensor. However, the rearview camera and ultrasonic sensor may be obscured. For example, dirt may accumulate on the camera or the ultrasonic sensor. In addition, objects behind the vehicle may not be within the line of sight of the rearview camera and ultrasonic sensor because obstacles on the side of the road (e.g., hedges, fences, walls, etc.) block the line of sight or changes in the angle of the road cause the sensor's line of sight to tilt upward, so that objects close to the ground (e.g., bicycles, pets, etc.) cannot be captured.

[0012] As described below, the vehicle monitors and classifies the sounds outside the vehicle. However, conventional condenser microphones (ECMs) are not constructed for external use. Their fragile microphone diaphragms may not be used due to dust, snow, rain or mud. Instead, because sound causes oscillations when passing through a medium, an accelerometer is placed on one or more edges of the vehicle's glass surface. When a pressure wave hits a window, the oscillation is measured as a vibration by the accelerometer. The resulting electrical output from the accelerometer is processed by a sound classifier that classifies the sound into importance categories (e.g., critical categories and non-critical categories, etc.) and / or identifies the sound. The vehicle provides an alert based on the category and / or identity of the sound. For example, a sound indicating human speech can be classified as critical, while a sound indicating average traffic noise can be classified as non-critical. The accelerometer is mounted on one or more windows (e.g., rear glass, left rear door glass, right rear door glass, etc.) at the rear of the vehicle. In addition, in some instances, the sound classifier operates in one of two modes. In a first mode (sometimes referred to as "passive mode"), the sound classifier causes the captured sound to be played on the vehicle's sound system when the sound is classified as critical. In a second mode (sometimes referred to as "active mode"), the sound classifier causes the captured sound to be played on the vehicle's sound system regardless of the classification of the sound.

[0013] Figure 1 A vehicle 100 operating in accordance with the teachings of the present disclosure is shown. The vehicle 100 may be a standard gasoline-powered vehicle, a hybrid vehicle, an electric vehicle, a fuel cell vehicle, and / or any other type of vehicle for implementation of mobility. The vehicle 100 includes portions related to mobility, such as a powertrain having an engine, a transmission, a suspension, a drive shaft, and / or wheels, etc. The vehicle 100 may be non-autonomous or semi-autonomous (e.g., some conventional motor functions are controlled by the vehicle 100). Alternatively, in some instances, the vehicle 100 may be an autonomous vehicle (e.g., conventional motor functions are controlled by the vehicle 100). In the illustrated example, the vehicle 100 includes a window 102, one or more accelerometers 104, a powertrain control unit (PCU) 106, an active safety module (ASM) 108, and an infotainment head unit (ITHU) 110.

[0014] The vehicle windows 102 include a windshield, a rear glass, a left front door glass, a left rear door glass, a right front door glass, a right rear door glass, and / or a sunroof. Some vehicle windows 102 are made of laminated glass (sometimes referred to as "safety glass") (e.g., windshields, etc.), while some vehicle windows 102 are made of non-laminated tempered glass (e.g., left front door glass, left rear door glass, right front door glass, right rear door glass, etc.). When hit by sound waves, the glass of the vehicle windows 102 vibrates.

[0015] The one or more accelerometers 104 can be any type of accelerometer that: (a) measures vibrations perpendicular to the glass plane of the corresponding window 102, and (b) measures a wide frequency range (e.g., the frequency range of audible sound, etc.), including single-axis or three-axis accelerometers, micromechanical or piezoelectric accelerometers, etc. The one or more accelerometers 110 are rigidly mounted on one or more windows 102 inside the cabin of the vehicle 100. In the example shown, the accelerometer 104 is mounted on the rear glass window. In some examples, in order to improve the arc behind the vehicle 100 where noise from obstacles is detected, the accelerometer 104 is mounted on other windows 102, such as the left rear door glass and / or the right rear door glass.

[0016] The powertrain control unit 106 includes hardware and firmware for controlling the ignition, fuel injection, emission system, transmission and / or braking system of the vehicle 100. The powertrain control unit 106 monitors sensors (such as fuel injection sensors, wheel speed sensors, exhaust sensors, etc.) and uses control algorithms to control, for example, the fuel mixture, ignition timing, variable cam timing, emission control, fuel pumps, engine cooling fans, and / or charging systems. In addition, the powertrain control unit 106 communicates the status of the vehicle 100 related to the powertrain (e.g., ignition status, transmission status, speed of the vehicle 100, etc.) to the vehicle data bus (e.g., below Figure 2 on the vehicle data bus 202).

[0017] The active safety module 108 includes hardware and software that detects and identifies objects close to the vehicle 100 based on images captured by one or more cameras (e.g., rearview camera 112, etc.) and / or distance detection sensors (e.g., ultrasonic sensor 114, etc.) using image recognition and spatial recognition techniques. The active safety module 108 classifies the objects and, in some instances, requests a warning to the driver based on the category of the detected object. The detection and identification of obstacles is used for various functions of the active safety module 108, such as traffic sign recognition and / or collision avoidance, etc.

[0018] The infotainment head unit 110 provides an interface between the vehicle 100 and a user. The infotainment head unit 110 includes digital and / or analog interfaces (e.g., input devices and output devices) to receive input from one or more users and display information. The input devices may include, for example, control knobs, instrument panels, digital cameras for image capture and / or visual command recognition, touch screens, audio input devices (e.g., cabin microphones), buttons, or touch pads. The output devices may include instrument cluster outputs (e.g., dials, lighting devices), actuators, heads-up displays, center console displays (e.g., liquid crystal displays (“LCDs”), organic light emitting diode (“OLED”) displays, flat panel displays, solid-state displays, etc.), and / or speakers. In the illustrated example, the infotainment head unit 110 includes a display for an infotainment system (e.g., of and MyFord of of The infotainment host unit 110 includes hardware (eg, processor or controller, memory, storage device, etc.) and software (eg, operating system, etc.). In addition, the infotainment host unit 110 displays the infotainment system on, for example, a center console display.

[0019] In the illustrated example, the infotainment head unit 110 includes a sound signature database 116 and an obstacle monitor 118 to detect and identify sounds of objects behind the vehicle 100 and provide an audio, visual, and / or tactile warning to the driver in the following two situations: (a) the rear view camera 112 and / or the rear ultrasonic sensor 114 are blocked or malfunctioning, and / or (b) the vehicle 100 is positioned such that the field of view 119 of the rear view camera 112 and / or the field of view 121 of the rear ultrasonic sensor 114 cannot observe the arc behind the vehicle 100 (e.g., the vehicle 100 is located on a hill, etc.). The obstacle monitor 118 processes the signal generated by one or more accelerometers 104, which is caused by sound waves contacting one or more corresponding vehicle windows 102. The obstacle monitor 118 compares the detected sound with the signatures in the sound signature database 116 and classifies the sound. Based on the classification, the obstacle monitor 118 provides an audio, visual, and / or tactile warning. For example, the obstacle monitor 118 can cause the sound system of the infotainment head unit 110 to sound a chime and cause the steering wheel control module to vibrate the steering wheel. In addition, in some examples, the obstacle monitor 118 plays sounds on the speakers 120 of the vehicle 100 depending on the mode selected by the user.

[0020] The sound signature database 116 contains signatures to be compared with the signals from the accelerometer 104 processed by the obstacle monitor 118. As used herein, a signature is an identifiable segment of a signal in the time domain or frequency domain associated with a sound source. For example, a signature may associate a signal in the frequency domain with a sound indicative of human speech or an animal call. The sound signature database 116 may be any suitable data structure that associates a time domain or frequency domain representation of a sound with an event, phenomenon, and / or source of the sound. The sound signature database 116 associates each signature with a category and an identifier. In some instances, the sound signature database 116 associates each signature with a natural language identifier (e.g., "cat," "traffic noise," etc.) and / or a sound file of the natural language identifier to be played on the speaker 120.

[0021] The obstacle monitor 118 determines whether the rear view camera 112 and / or the rear ultrasonic sensor 114 are blocked or malfunctioning (e.g., not providing data / images, etc.). In some examples, to determine whether the rear view camera 112 is blocked (e.g., by snow or mud, etc.), the obstacle monitor 118 analyzes the average light intensity of the pixels of the image captured by the rear view camera 112. For example, when the average light intensity of the pixels is low, the rear view camera 112 is likely blocked. Alternatively or additionally, in some examples, to determine whether the rear view camera 112 is blocked, the obstacle monitor 118 analyzes the light intensity of the pixels of the image captured by the rear view camera 112 to determine whether a majority of the pixels have substantially similar pixel intensities.

[0022] The obstacle monitor 118 filters and processes the signal caused by the sound waves interacting with one or more vehicle windows 102 in the time domain and the frequency domain. The obstacle monitor 118 compares the processed signal with the signature in the sound signature database 116 to identify the signal source and classifies the sound source into importance categories. For example, the obstacle monitor can classify the sound as critical or non-critical. The critical sound is the sound originating from the object 122, which is likely to be behind the vehicle 100 or soon behind the vehicle 100. For example, the critical sound may include human voices, animal sounds, horns (e.g., car horns, etc.) and / or ringtones (e.g., bicycle bells, etc.). Non-critical sounds are sounds that may be ambient or environmental sounds, such as music, traffic noise, rain, etc. In some instances, the obstacle monitor 118 adjusts the category of the sound based on the intensity of the sound detected by the accelerometer 104 (e.g., in decibel-milliwatts (dBm)). For example, if the intensity of the sound is less than a threshold, the sound associated with the object classified as critical can be classified as non-critical. In this manner, obstacle monitor 118 distinguishes between objects 122 that are close to the rear of vehicle 100 and objects 122 that are close to the vehicle.

[0023] When the rearview camera 112 and / or the rear ultrasonic sensor 114 are not obstructed, the identity of the object 122 behind the vehicle 100 generated by the active safety module 108 is prioritized. That is, when the active safety module 108 identifies the object 122 in the key category, the obstacle monitor 118 provides an audio, visual, and / or tactile alert associated with the identity of the object 122 determined by the active safety module 108. However, even when the identity of the object 122 behind the vehicle 100 generated by the active safety module 108 is prioritized, the obstacle monitor 118 still independently attempts to identify the source of the sound (e.g., the object 122). In an example scenario (e.g., as Figure 1), the vehicle 100 may be positioned on a hillside such that the object 122 generating the sound is outside the field of view 119 of the rearview camera 112 and the field of view 121 of the ultrasonic sensor 114. In such an example scenario, the obstacle detector 118 may provide the identity of the object 122 even when the unobstructed rearview camera 112 and the ultrasonic sensor 114 cannot observe the object 122.

[0024] When the rearview camera 112 and / or the rear ultrasonic sensor 114 are blocked, the obstacle monitor 118 provides the identity of the sound to the active safety module 108. In addition, when the obstacle monitor 118 identifies the object 122 based on the sound detected by the accelerometer 104 in the critical category, the obstacle monitor 118 provides an audio, visual and / or tactile alert associated with the identity of the object 122 in the sound signature database 116. In some examples, the alert includes a natural language identifier associated with the detected object 122. For example, when the obstacle monitor 118 determines that the object 122 is a dog, the obstacle monitor 118 can cause "Warning Dog May Be Behind Vehicle" to be played on the speakers 120 of the vehicle 100. In some examples, when the sound is classified as critical, the obstacle monitor 118 instructs the powertrain control unit 106 to apply the brakes of the vehicle 100 to stop the movement of the vehicle 100 in reverse. That is, the obstacle monitor 118 causes the vehicle 100 to brake autonomously and ignore the input of the accelerator pedal.

[0025] In some examples, the obstacle monitor 118 operates in different modes, wherein the obstacle monitor 118 reacts differently to detected objects based on the class assigned to the object 122. In some such examples, the obstacle monitor 118 operates in a "passive mode" and an "active mode." In the passive mode, the obstacle monitor 118 provides an alert and plays a sound detected by the accelerometer 104 on the speaker 120 when the object 122 is classified as critical. When the obstacle monitor 118 operates in the active mode, the obstacle monitor 118 plays a sound detected by the accelerometer 104 on the speaker 120 regardless of the class associated with the object 122. In some examples, the obstacle monitor 118 operates in a "stationary mode," wherein the obstacle monitor 118 provides an alert and plays a sound detected by the accelerometer 104 on the speaker 120 when the vehicle 100 is stationary and the transmission is in park. In this way, the obstacle monitor 118 provides an alert when, for example, the rear view camera (and therefore the rear glass) is obscured by adverse weather conditions (eg, snow, etc.), and provides information to the occupants of the vehicle 100 to exit the vehicle 100 .

[0026] In some examples, when the vehicle 100 is an autonomous vehicle, the obstacle detector 118 augments other autonomous functions of the vehicle 100. For example, when one or more rear sensors of the vehicle 100 are blocked, the autonomous vehicle can use the recognized sound as a source of information to facilitate parking in an emergency area. In addition, in such examples, the vehicle 100 can provide information to the occupants of the vehicle 100 to leave the vehicle 100.

[0027] Figure 2 yes Figure 1 1 is a block diagram of an electronic component 200 of a vehicle 100. In the example shown, the electronic component 200 includes one or more accelerometers 104, a powertrain control unit 106, an active safety module 108, an infotainment head unit 110, a rearview camera 112, an ultrasonic sensor 114, a speaker 120, and a vehicle data bus 202.

[0028] The infotainment head unit 110 includes a processor or controller 204 and a memory 206. In the illustrated example, the infotainment head unit 110 is configured to include an obstacle detector 118. The processor or controller 204 may be any suitable processing device or group of processing devices, such as, but not limited to: a microprocessor, a microcontroller-based platform, a suitable integrated circuit, one or more field programmable gate arrays (FPGAs), and / or one or more application-specific integrated circuits (ASICs). The memory 206 may be a volatile memory (e.g., RAM, which may include non-volatile RAM, magnetic RAM, ferroelectric RAM, and any other suitable form); a non-volatile memory (e.g., disk memory, flash memory, electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), non-volatile solid-state memory, etc.), an unchangeable memory (e.g., EPROM), a read-only memory, and / or a high-capacity storage device (e.g., a hard disk drive, a solid-state drive, etc.). In some examples, the memory 206 includes a variety of memories, particularly volatile memories and non-volatile memories. In the illustrated example, the memory 206 includes the sound signature database 116.

[0029] The memory 206 is a computer-readable medium on which one or more sets of instructions such as software for operating the methods of the present disclosure may be embedded. The instructions may embody one or more methods or logic as described herein. In certain embodiments, the instructions may reside completely or at least partially in any one or more of the memory 206, the computer-readable medium, and / or in the processor 204 during the execution of the instructions.

[0030] The terms "non-transitory computer-readable medium" and "tangible computer-readable medium" should be understood to include a single medium or multiple media, such as centralized or distributed databases, and / or associated caches and servers storing one or more sets of instructions. The terms "non-transitory computer-readable medium" and "tangible computer-readable medium" also include any tangible medium capable of storing, encoding, or carrying a set of instructions for execution by a processor or causing a system to perform any one or more of the methods or operations disclosed herein. As used herein, the term "tangible computer-readable medium" is expressly defined to include any type of computer-readable storage device and / or storage disk and excludes propagating signals.

[0031] The vehicle data bus 202 communicatively couples the powertrain control unit 106, the active safety module 108, and the infotainment head unit 110. In some examples, the vehicle data bus 202 includes one or more data buses. The vehicle data bus 202 may be configured in accordance with the controller area network (CAN) bus protocol defined by the International Organization for Standardization (ISO) 11898-1, the media oriented system transport (MOST) bus protocol, the CAN flexible data (CAN-FD) bus protocol (ISO 11898-7), and / or the K-line bus protocol (ISO 9141 and ISO 14230-1), and / or Ethernet. TM Bus protocol IEEE 802.3 (since 2002) and others have been implemented.

[0032] Figure 3 Is installed using Figure 1 A flowchart of a method for providing a back-up assist using an accelerometer 104 on the rear glass of a vehicle 100, which may be Figure 2100 is implemented in an electronic component 200 of the vehicle 100. Initially, at box 302, the obstacle monitor 118 waits until the ignition of the vehicle 100 is turned on. At box 304, the obstacle monitor 118 waits until the transmission of the vehicle 100 is in reverse gear. At box 306, the obstacle monitor 118 determines the state of the rearview camera 112 and / or the ultrasonic sensor 114 (e.g., blocked, unblocked, etc.). In some examples, the obstacle monitor 118 analyzes the data captured by the rearview camera 112 and / or the ultrasonic sensor 114 to determine whether the data indicates that the rearview camera 112 and / or the ultrasonic sensor 114 is blocked. For example, the obstacle monitor 118 may perform pixel analysis on the image captured by the rearview camera 112 to determine whether the light level in the image indicates that the rearview camera 112 is blocked by snow. At box 308, the obstacle monitor 118 determines whether the rearview camera 112 and / or the ultrasonic sensor 114 is blocked or blocked. When the rear view camera 112 and / or the ultrasonic sensor 114 is blocked or obstructed, the method continues at frame 310. Otherwise, when the rear view camera 112 and / or the ultrasonic sensor 114 is not blocked or obstructed, the method continues at frame 316.

[0033] At box 310, the obstacle monitor 118 prioritizes obstacle detection based on sounds detected by the accelerometer 104 mounted on the rear glass of the vehicle 100. At box 312, the obstacle monitor 118 determines whether the accelerometer 104 detects sounds. When the accelerometer 104 detects sounds, the method continues at box 314. Otherwise, when the accelerometer 104 does not detect sounds, the method returns to box 302. At box 314, the obstacle monitor 118 classifies the sounds detected by the accelerometer and assigns a category to the sounds. In some examples, the obstacle monitor 118 filters and processes (e.g., in the time domain, in the frequency domain) the sounds and compares them to signatures in the sound signature database 116.

[0034] At box 316, the obstacle monitor 118 prioritizes obstacle detection based on the analysis of the active safety module 108. At box 318, the obstacle monitor 118 determines whether the accelerometer 104 detects the sound. When the accelerometer 104 detects the sound, the method continues at box 314. Otherwise, when the accelerometer 104 does not detect the sound, the method continues at box 320. At box 320, the obstacle monitor 118 does not provide an alert.

[0035] At box 322, the obstacle monitor 118 determines whether it is in passive mode. When the obstacle monitor 118 is in passive mode, the method continues at box 324. Otherwise, when the obstacle monitor 118 is in active mode, the method continues at box 330. At box 324, the obstacle monitor 118 determines whether the sound is classified as critical at box 314. When the sound is classified as critical, the method continues at box 326. Otherwise, when the sound is not classified as critical, the method returns to box 302. At box 326, the obstacle monitor 118 provides an audio, visual and / or tactile alert to the driver. At box 328, the obstacle monitor 118 plays the sound through the speaker 120 of the sound system. At box 330, the obstacle monitor 118 determines whether the sound is classified as critical at box 314. When the sound is classified as being critical, the method continues at box 326 to provide an audio, visual and / or tactile alert to the driver. Otherwise, when the sound is not classified as being critical, the method continues at box 328 to play the sound through the speaker 120 of the sound system.

[0036] Figure 3 A flowchart representing a memory device (such as Figure 2 206) in a memory 206) of a processor, the machine-readable instructions comprising one or more programs, when executed by a processor (such as Figure 2 When executed by the processor 204, the program causes the infotainment host unit 110 to implement Figure 1 and Figure 2 118 of an exemplary obstacle detector. In addition, although reference is made to Figure 3 The flowchart shown in describes one or more exemplary procedures, but many other methods of implementing the exemplary obstacle monitor 118 may alternatively be used. For example, the order of execution of the blocks may be changed, and / or some of the blocks described may be changed, eliminated, or combined.

[0037] An example vehicle includes an accelerometer mounted on the inner surface of a rear window of the vehicle, a rear view camera, and a processor. The processor identifies a sound source causing vibrations on the rear window, which are captured by the accelerometer. The processor also classifies the sound and provides an alert based on the category of the sound.

[0038] In some instances, the processor determines whether the rearview camera is obstructed, and when the rearview camera is obscured, the identity of the source is provided to other vehicle subsystems. In some such instances, to determine whether the rearview camera is obstructed, the processor performs a pixel-level analysis of the light intensity of the image captured by the rearview camera. In some instances, the memory stores a database of sound signatures. To identify the source of the sound, the processor processes the sound to produce an observed signature; and compares the observed signature with the signature stored in the database of sound signatures. In some instances, the processor classifies the sound into a first category or a second category. In some such instances, the processor provides an alert when the sound is assigned to the first category, and does not provide an alert when the sound is assigned to the second category. In some such instances, the processor determines an operating mode of the vehicle. In some such instances, when the vehicle is operating in the first mode, the processor plays the sound through the speaker of the vehicle when the sound is classified in the first category. In some such instances, when the vehicle is operating in the second mode, the processor plays the sound through the speaker of the vehicle regardless of how the sound is classified.

[0039] An example method of monitoring an area behind a vehicle includes measuring a signal using an accelerometer mounted on the inner surface of a rear window of the vehicle, the signal being caused by sound waves vibrating the rear window. The method also includes identifying a source of the sound waves and classifying the source. Additionally, the example includes providing an alert based on the classification of the source.

[0040] In some instances, to determine whether a rearview camera is obstructed, the method includes performing a pixel-level analysis of the light intensity of an image captured by the rearview camera. In some instances, to identify and classify a source, the method includes processing a signal measured by an accelerometer to generate an observed signature, and comparing the observed signature to a signature stored in a sound signature database. In some instances, the method includes providing an alert when the sound is assigned to a first category and not providing an alert when the sound is assigned to a second category. In some instances, the method includes: (a) when the vehicle is operating in a first mode, playing a sound wave through a speaker of the vehicle when the sound is classified in the first category, and (b) when the vehicle is operating in a second mode, playing a sound wave through a speaker of the vehicle regardless of how the sound is classified.

[0041] In this application, the use of transitional conjunctions is intended to include conjunctions. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, reference to "the" object or "one" and "a" object is intended to also represent one of a possible plurality of such objects. In addition, the conjunction "or" can be used to convey simultaneous features rather than mutually exclusive alternatives. In other words, the conjunction "or" should be understood to include "and / or". As used herein, the terms "module" and "unit" refer to hardware with circuits that are typically combined with sensors to provide communication, control and / or monitoring capabilities. "Modules" and "units" may also include firmware executed on the circuit. The term "includes" is inclusive and has the same scope as "includes" and "contains".

[0042] The above embodiments, particularly any "preferred" embodiments, are examples of possible implementations and are presented merely for a clear understanding of the principles of the present invention. Many changes and modifications may be made to the above embodiments without substantially departing from the spirit and principles of the technology described herein. All modifications are intended to be included within the scope of this disclosure and to be protected by the appended claims.

Claims

1. A vehicle comprising: an accelerometer mounted on an inner surface of a rear window of the vehicle; Rear view camera; and A processor, the processor being configured to: identifying a source of sound causing vibrations on the rear window, the vibrations being captured by the accelerometer; categorizing the sounds; providing an alert based on the category of the sound; Determining whether the rearview camera is blocked; as well as When the rear view camera is obscured, the identity of the source is provided to other vehicle subsystems.

2. The vehicle of claim 1, wherein the processor is configured to: Priorities of the rear view camera and the accelerometer are determined based on a result of determining whether the rear view camera is blocked. 3 . The vehicle of claim 1 , wherein to determine whether the rear view camera is obscured, the processor is configured to perform a pixel-level analysis of light intensity of an image captured by the rear view camera.

4. The vehicle of claim 1 including a memory storing a database of sound signatures, and wherein to identify the source of the sound, the processor is configured to: processing the sound to produce an observed signature; and The observed signature is compared to signatures stored in the acoustic signature database.

5. The vehicle of claim 1 or claim 4, wherein the processor is configured to classify the sound into a first category or a second category. 6 . The vehicle of claim 5 , wherein the processor is configured to provide the alert when the sound is assigned to the first category and not provide the alert when the sound is assigned to the second category.

7. The vehicle of claim 5, wherein the processor is used to determine an operating mode of the vehicle.

8. The vehicle of claim 7, wherein when the vehicle is operating in a first mode, the processor is to play the sound through a speaker of the vehicle when the sound is classified in the first category.

9. The vehicle of claim 8, wherein the processor is configured to play the sound through the speaker of the vehicle when the vehicle is operating in the second mode regardless of how the sound is classified.

10. A method for monitoring an area behind a vehicle, the method comprising: measuring, using an accelerometer mounted on an inner surface of a rear window of the vehicle, a signal caused by the sound waves vibrating the rear window; identifying, with a processor coupled to a memory containing a database of sound signatures, a source of the sound wave; categorizing said sources; providing an alert based on the category of the source; Determine whether the rear view camera is blocked; as well as When the rear view camera is obscured, the identity of the source is provided to other vehicle subsystems.

11. The method according to claim 10, comprising: Priorities of the rear view camera and the accelerometer are determined based on a result of determining whether the rear view camera is blocked.

12. The method of claim 10, wherein determining whether the rear view camera is blocked comprises: A pixel-level analysis is performed on the light intensity of the image captured by the rear view camera.

13. The method of claim 10, wherein identifying and classifying the source comprises: processing the signal measured by the accelerometer to produce an observed signature; as well as The observed signature is compared to signatures stored in the acoustic signature database.

14. A method according to claim 10 or claim 13, comprising: The alert is provided when the sound wave is assigned to a first category, and the alert is not provided when the sound wave is assigned to a second category.

15. The method according to claim 10 or claim 13, comprising: when the vehicle is operating in a first mode, playing the sound waves through a speaker of the vehicle when the sound waves are classified in a first category; as well as When the vehicle is operating in the second mode, the sound waves are played through the speakers of the vehicle regardless of how the sound waves are classified.

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