Method and device for planary sensory detection
First Claim
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1. A method for determining a presence of an object comprising:
- detecting a movement and location of an object within a sensory space by tracking ultrasonic signals directed to and reflected off the object;
estimating a phase angle of received waveforms for each of three transmit and receive pair transducers generating the sensory space;
saving a history of received ultrasonic waveforms reflected off the object to within a predetermined time range according to the phase angle;
creating a three-dimensional volumetric surface from the phase angles for each of the transmit and receive pair transducerscalculating therefrom a broad intersection region of the three-dimensional volumetric surfaces;
in addition to the phase angle, estimating a phase difference between successively received ultrasonic waveforms in the history of the movement;
evaluating the phase difference to less than a wavelength of the received ultrasonic signals where the phase angle of the ultrasonic waveforms is within the predetermined range, andconstraining the location of the object to a particular point within the intersection of the three-dimensional volumetric surfaces from the phase difference;
and,resolving the location of the object with approximately a positional accuracy of one millimeter in the sensory space.
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Abstract
A method and system (500) for generating an approximately planar sensory field (199) and confirming a presence of an object (310) in the field is provided. The system can include at least one paired receiver (121/122) and at least one transmitter (130) in a front and back orientation of a touchless sensing unit (110). The method can include detecting a movement of the object within a sensory space (176/177), estimating a phase angle of the movement; and evaluating whether the phase angle is within a predetermined range (197), and if so, confirming a presence of the object within the approximately planar sensory field.
135 Citations
15 Claims
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1. A method for determining a presence of an object comprising:
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detecting a movement and location of an object within a sensory space by tracking ultrasonic signals directed to and reflected off the object; estimating a phase angle of received waveforms for each of three transmit and receive pair transducers generating the sensory space; saving a history of received ultrasonic waveforms reflected off the object to within a predetermined time range according to the phase angle; creating a three-dimensional volumetric surface from the phase angles for each of the transmit and receive pair transducers calculating therefrom a broad intersection region of the three-dimensional volumetric surfaces; in addition to the phase angle, estimating a phase difference between successively received ultrasonic waveforms in the history of the movement; evaluating the phase difference to less than a wavelength of the received ultrasonic signals where the phase angle of the ultrasonic waveforms is within the predetermined range, and constraining the location of the object to a particular point within the intersection of the three-dimensional volumetric surfaces from the phase difference; and, resolving the location of the object with approximately a positional accuracy of one millimeter in the sensory space. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A sensing unit for accurately determining a location of an object comprising:
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at least one transmitter for transmitting a plurality of ultrasonic signal pulses; at least three receivers for each respectively capturing a first reflection and a second reflection of the ultrasonic signal pulses from an object in a sensing space created by the at least one transmitter and receivers; and a processor for accurately detecting a location and movement of an object within the sensory field by; tracking ultrasonic signals directed to and reflected off the object, saving received ultrasonic signals reflected off the object to memory, estimating a phase angle of received ultrasonic signals in the history of the movement; in addition to the phase angle, estimating a phase difference between peak amplitudes of successively received ultrasonic signals in the history creating a three-dimensional volumetric surface from the phase angle for transmit and receiver pairs and calculating therefrom an intersection of the three-dimensional volumetric surfaces; and evaluating the phase difference to is less than a wavelength of the received ultrasonic signals where the wavelength is the ratio of the speed of sound to the ultrasonic signal fundamental frequency that is between 40 Khz and 120 KHz, and the phase angle is within a predetermined time of flight range, and locating the object with a positional accuracy on the order of one millimeter in the sensory space by constraining the detected location of the object to an intersection point of the three-dimensional volumetric surfaces from the phase difference. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for accurate ultrasonic sensing, comprising:
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emitting a plurality of ultrasonic signals in air from a transmitter with a fundamental frequency between 40 to 120 KHz for generating a sensory space therein; detecting a location and movement of an object within the sensory space by tracking the ultrasonic signals directed to and reflected off the object; saving a history of received ultrasonic signals reflected off the object within a predetermined range; estimating a phase angle of the received ultrasonic signals stored in the history of the movement for each transmitter and receiver pair; estimating a phase difference between peak amplitudes of successively received ultrasonic signals stored in the history for each transmitter and receiver pair, and creating a three-dimensional volumetric surface from the phase angle measurements for each of three transmit and receive pair transducers and calculating therefrom an intersection of the three-dimensional volumetric surfaces; constraining the location of the object to a region within the intersection of the three-dimensional volumetric surfaces by evaluating the phase difference to less than a wavelength of the received ultrasonic signals; determining that the object is at a location with approximately a positional accuracy of one millimeter in the sensory space when the phase difference is less than a wavelength of the received ultrasonic signals and the phase angle is within the predetermined range, where the wavelength is the ratio of the speed of sound to the ultrasonic signal fundamental frequency, and the fundamental frequency is between 40 Khz and 120 KHz. - View Dependent Claims (14, 15)
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Specification