Techniques for presence-detection devices to detect movement of a person in an environment by emitting ultrasonic signals using a loudspeaker that is concurrently outputting audible sound. To detect movement by the person, the devices characterize the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. However, when a loudspeaker plays audible sound while emitting the ultrasonic signal, audio signals generated by microphones of the devices include distortions caused by the loudspeaker. These distortions can be interpreted by the presence-detection devices as indicating movement of a person when there is no movement, or as indicating lack of movement when a user is moving. The techniques include processing audio signals to remove distortions to more accurately identify changes in the frequency of the reflections of the ultrasonic signals caused by the movement of the person.

A level measuring device is provided. The level measuring device can be configured to monitor the surface topology of a bulk material, and can include a sensor unit for scanning several areas of the bulk material surface and an evaluation unit for calculating the volumes under these areas.

A level measuring device is provided. The level measuring device can be configured to monitor the surface topology of a bulk material, and can include a sensor unit for scanning several areas of the bulk material surface and an evaluation unit for calculating the volumes under these areas.

In some embodiments, the present disclosure relates a process tool that includes a chamber housing defining a processing chamber. Within the processing chamber is a workpiece holder apparatus that is configured to hold a workpiece. A sonar sensor is arranged over the workpiece holder apparatus. The sonar sensor includes an emitter that is configured to produce sound waves traveling towards the workpiece holder apparatus. The sonar sensor also includes a detector that is configured to receive reflected sound waves from the workpiece holder apparatus or an object between the sonar sensor and the workpiece holder apparatus. Further, sonar sensor control circuitry is coupled to the sonar sensor and is configured to determine if a workpiece is present on the workpiece holder apparatus based on a sonar intensity value of the reflected sound waves received by the detector of the sonar sensor.

In some embodiments, the present disclosure relates a process tool that includes a chamber housing defining a processing chamber. Within the processing chamber is a workpiece holder apparatus that is configured to hold a workpiece. A sonar sensor is arranged over the workpiece holder apparatus. The sonar sensor includes an emitter that is configured to produce sound waves traveling towards the workpiece holder apparatus. The sonar sensor also includes a detector that is configured to receive reflected sound waves from the workpiece holder apparatus or an object between the sonar sensor and the workpiece holder apparatus. Further, sonar sensor control circuitry is coupled to the sonar sensor and is configured to determine if a workpiece is present on the workpiece holder apparatus based on a sonar intensity value of the reflected sound waves received by the detector of the sonar sensor.

An interferometric synthetic aperture acoustic imager is disclosed. Specifically, an acoustic imaging system includes an acoustic transmitter, an acoustic receiver array, a signal processing system, a navigation data system, and a meteorological data system. The acoustic transmitter and the acoustic receiver array are mounted on transceiver array. The navigation data system includes a Position and Orientation System for Land Vehicles system which receives data from two Global Positioning System antennas, an inertial measurement unit, and a wheel encoder mounted on a vehicle wheel. The system also includes meteorological data system that records temperature, relative humidity, and barometric pressure. The meteorological data may be used to adjust the received acoustic data based on atmospheric conditions.

An interferometric synthetic aperture acoustic imager is disclosed. Specifically, an acoustic imaging system includes an acoustic transmitter, an acoustic receiver array, a signal processing system, a navigation data system, and a meteorological data system. The acoustic transmitter and the acoustic receiver array are mounted on transceiver array. The navigation data system includes a Position and Orientation System for Land Vehicles system which receives data from two Global Positioning System antennas, an inertial measurement unit, and a wheel encoder mounted on a vehicle wheel. The system also includes meteorological data system that records temperature, relative humidity, and barometric pressure. The meteorological data may be used to adjust the received acoustic data based on atmospheric conditions.

An object detection system includes: a plurality of object detection units. The object detection units each include a transmission and reception unit configured to transmit an ultrasonic wave and receive a reflected wave generated by reflection of the ultrasonic wave on an object, a reception circuit unit configured to detect a signal level of the reflected wave received by the transmission and reception unit, a detection unit configured to detect the object by comparing the signal level detected by the reception circuit unit with a predetermined signal threshold value, a temperature sensor configured to detect a temperature of an environment, and a detection sensitivity adjustment unit configured to adjust detection sensitivity of the reception circuit unit based on a second lowest temperature among temperatures detected by the respective temperature sensors in the plurality of object detection units.

An object detection system includes: a plurality of object detection units. The object detection units each include a transmission and reception unit configured to transmit an ultrasonic wave and receive a reflected wave generated by reflection of the ultrasonic wave on an object, a reception circuit unit configured to detect a signal level of the reflected wave received by the transmission and reception unit, a detection unit configured to detect the object by comparing the signal level detected by the reception circuit unit with a predetermined signal threshold value, a temperature sensor configured to detect a temperature of an environment, and a detection sensitivity adjustment unit configured to adjust detection sensitivity of the reception circuit unit based on a second lowest temperature among temperatures detected by the respective temperature sensors in the plurality of object detection units.

Ultrasonic audio processing circuitry and a method useful in ultrasonic presence detection. An ultrasonic burst generator produces an ultrasonic burst signal at one or more ultrasonic frequencies, and an equalizer equalizes that ultrasonic burst signal according to frequency response characteristics of the speaker and microphone at those ultrasonic frequencies. Driver circuitry drives a speaker with the ultrasonic burst signal, which may be combined with an audible audio signal. An ultrasonic separation filter separates an ultrasonic portion from a signal received at a microphone, and processing circuitry is provided to determine a delay time of an echo corresponding to the ultrasonic burst signal in that separated ultrasonic portion of the received signal. In another aspect, the equalizer equalizes an ultrasonic portion of the signal received at a microphone, according to frequency response characteristics of the speaker and microphone at the ultrasonic frequencies of the burst.