An example playback device is configured to (i) detect, while the graphical display is in a sleep state, that a user is proximate to the playback device, (ii) cause a graphical display to exit a sleep state and present a GUI including a list of selectable quick start icons, each quick start icon corresponding to a respective command to begin playback of respective media content, where the list does not include information identifying the respective media content, (iii) determine that a predetermined period of time has passed after causing the graphical display to exit the sleep state, (iv) update the graphical display to include information identifying the respective media content corresponding to each quick start icon, (v) detect an input selecting one of the quick start icons via the graphical display, and (vi) based on detecting the input, begin to play back the media content corresponding to the selected one of the quick start icons.

An example playback device is configured to (i) detect, while the graphical display is in a sleep state, that a user is proximate to the playback device, (ii) cause a graphical display to exit a sleep state and present a GUI including a list of selectable quick start icons, each quick start icon corresponding to a respective command to begin playback of respective media content, where the list does not include information identifying the respective media content, (iii) determine that a predetermined period of time has passed after causing the graphical display to exit the sleep state, (iv) update the graphical display to include information identifying the respective media content corresponding to each quick start icon, (v) detect an input selecting one of the quick start icons via the graphical display, and (vi) based on detecting the input, begin to play back the media content corresponding to the selected one of the quick start icons.

A travel speed sensing system includes an optical sensor configured to be coupled to a welding torch. The optical sensor is configured to sense light incident on the optical sensor, and the travel speed sensing system is configured to determine a travel speed of the welding torch, a direction of the welding torch, or both, based on the sensed light.

A travel speed sensing system includes an optical sensor configured to be coupled to a welding torch. The optical sensor is configured to sense light incident on the optical sensor, and the travel speed sensing system is configured to determine a travel speed of the welding torch, a direction of the welding torch, or both, based on the sensed light.

In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.

In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.

The present invention discloses a method and system for determining a horizontal distance between a transmitting point and a receiving point. The method obtains a depth value of the transmitting point and a depth value of the receiving point. An area of a sound velocity profile according to the depth value of the transmitting point and the depth value of the receiving point is then determined. A sound velocity gradient according to the area of the sound velocity profile is also determined. The horizontal distance between the transmitting point and the receiving point according to the sound velocity gradient is then determined by calculations. The present invention eliminates the need to calculate a grazing angle of an eigen sound ray(wave) connecting the transmitting point and the receiving point, by directly converting a propagation time into the horizontal distance, thereby quickly and efficiently calculating the horizontal distance between the transmitting point and the receiving point.

The present invention discloses a method and system for determining a horizontal distance between a transmitting point and a receiving point. The method obtains a depth value of the transmitting point and a depth value of the receiving point. An area of a sound velocity profile according to the depth value of the transmitting point and the depth value of the receiving point is then determined. A sound velocity gradient according to the area of the sound velocity profile is also determined. The horizontal distance between the transmitting point and the receiving point according to the sound velocity gradient is then determined by calculations. The present invention eliminates the need to calculate a grazing angle of an eigen sound ray(wave) connecting the transmitting point and the receiving point, by directly converting a propagation time into the horizontal distance, thereby quickly and efficiently calculating the horizontal distance between the transmitting point and the receiving point.

The present invention provides a range-finding method, apparatus, system, and non-transitory computer-readable storage medium. The method includes: acquiring a predicted number of interrupts of a single-chip microcomputer; acquiring a to-be-measured signal; triggering a first output of a comparator according to a strength of the to-be-measured signal and a preset trigger threshold; recording an ultrasonic signal and acquiring an actual number of interrupts according to the first output; and adjusting the trigger threshold according to the predicted number of interrupts and the actual number of interrupts, where the adjusted trigger threshold is used to trigger the first output next time. The trigger threshold of the comparator can be adaptively adjusted according to the number of interrupts to adjust sensitivity of recording the ultrasonic signal, so as to adapt to different measurement environments and ranges, accurately record an arrival time of the ultrasonic signal, and improve the accuracy of a range-finding result.

A method of determining a distance between a vehicle and a sound source includes detecting, at a microphone of the vehicle, sounds from a sound source external to the vehicle. The sounds have a first frequency component at a first frequency and a second frequency component at a second frequency. The method also includes determining, at a processor of the vehicle, a classification of the sound source based on audio properties of the sounds. The method further includes determining a first energy level associated with the first frequency component and a second energy level associated with the second frequency component. The method also includes determining a ratio between the first energy level and the second energy level. The method further includes determining the distance between the vehicle and the sound source based on the ratio and the classification of the sound source.