Recent Patents in Signal Processing (March 2016) – time of flight technologies

For our March 2016 issue, we cover recent patents granted in the area of time of flight technology development and applications, used for mobile device communication, tomography, 3D localization, dynamic range control and range imaging systems.

Patent no. 9,270,319 introduces a mobile device case for functional connection and physical attachment to a mobile device. The mobile device case comprises an application adapted to run in the mobile device and a cradle configured for removable attachment with the mobile device. The cradle is comprising a controller capable of functional connection with the application, where the cradle is adapted to protect the mobile device while attached to the mobile device and the cradle is adapted to functionally pair with the application to create at least a portion of a mesh network.

In patent no. 9,261,580, a system for time-of-flight (ToF) positioning in an IEEE 802.11 network comprises an initiating station that transmits a request frame over a channel to a responding station for a ToF position measurement. The responding station may respond with an offloading of the channel information, request frame receipt time, and response frame transmit time back to the initiating station to enable the initiating station to calculate the ToF position with respect to the responding station.

Patent no. 9,241,678 introduces a method of estimating random events in positron emission tomography list mode data, including obtaining time-of-flight (TOF) list mode count data that includes TOF information; converting the obtained TOF list mode count data into four-dimensional (4D) raw sinogram count data, without using the TOF information, wherein the 4D raw sinogram count data includes random count values; interpolating the 4D raw sinogram count data to generate 4D interpolated sinogram count data; low-pass filtering the 4D interpolated sinogram count data to remove noise; converting the low-pass filtered 4D interpolated sinogram count data into filtered 4D raw sinogram count data; and generating, by a processor, five-dimensional (5D) TOF raw sinogram count data from the filtered 4D raw sinogram count data by effectively applying a TOF mask filter to the filtered 4D raw sinogram count data.

Volume dimensioning in patent no. 9,234,782 employs techniques to reduce multipath reflection or return of illumination, and hence distortion. Volume dimensioning for any given target object includes a sequence of one or more illuminations and respective detections of returned illumination. A sequence typically includes illumination with at least one initial spatial illumination pattern and with one or more refined spatial illumination patterns. Refined spatial illumination patterns are generated based on previous illumination in order to reduce distortion. The number of refined spatial illumination patterns in a sequence may be fixed, or may vary based on results of prior illumination(s) in the sequence. Refined spatial illumination patterns may avoid illuminating background areas that contribute to distortion. Sometimes, illumination with the initial spatial illumination pattern may produce sufficiently acceptable results, and refined spatial illumination patterns in the sequence omitted.

Invention no. 9,232,357 presents a method and system for indoor location of a mobile device, including: a server, the server adapted to calculate a position of a mobile device within a predefined area; a Master Beacon including: a first radio communications capability, a second radio communications capability, and a master processor, adapted to send data relating to the scan request packets via the second radio communications capability to the server, the data being sent together with a time stamp reflecting a time of receiving the scan request packets; and a plurality of Slave Beacons, each including: the first radio communications capability, a slave processor, adapted to send data relating to the scan request packets to the server, together with a time stamp; the server is adapted to calculate a respective distance of each the beacons from the mobile device.

A detailed in patent no. 9,229,096, electronic devices may include time-of-flight image pixels. A time-of-flight image pixel may include first and second charge storage regions coupled to a photosensor and a transfer transistor with a gate terminal coupled to the first storage region. An electronic device may further include a light pulse emitter configured to emit pulses of light to be reflected by objects in a scene. Reflected portions of the emitted pulses of light may be captured along with background light by the time-of-flight image pixels. Time-of-flight image pixels may be configured sense the time-of-flight of the reflected portions of the emitted pulses. The electronic device may include processing circuitry configured to use the sensed time-of-flight of the reflected portions to generate depth images of a scene. Depth images may include depth-image pixel values that contain information corresponding to the distance of the objects in the scene from the electronic device.

Patent no 9,220,078 introduces a method for synchronizing a clock of a frequency originator device (FOD) and a clock of a frequency receiver device (FRD), the method including disposing an information storage device at a known distance from the FOD, wherein a broadcast frequency of the FOD and the known distance are configured to be stored in the information storage device; obtaining by the FRD, the known distance between the FOD and the FRD and the broadcast frequency of the FOD; receiving a broadcast of the FOD by said FRD at the broadcast frequency according to the FRD's clock time at T2, wherein the broadcast was made at time t1 according to the FOD's clock time; calculating a time of flight (TOF) based on the known distance and the broadcast speed; and incorporating a time correction=T2-(t1+TOF) in calculations of TOF between the FOD and the FRD.

In patent no 9,218,949 a mass spectrometer of the type useful in mass cytometry includes an ion detector. A digitizing system for converting analog signals from the ion detector includes two analog-to-digital converters. The analog-to-digital converters are configured to provide an increased dynamic range for a targeted period while limiting the amount of data generated.

In the invention no. 9,194,943 a ranging system includes a time of flight subsystem including circuitry incorporated in a mobile node and a base station for generating a TOF signal between the mobile node and the base station, measuring the time taken for transmission of the TOF signal, and generating a TOF distance signal based on the measured time. An accelerometer, mounted in the mobile node, generates an accelerometer signal. A distance filter generates the distance estimate. The filter is configured to (i) initialize the value of a distance estimate signal based on the TOF distance signal, (ii) detect a human step based on variances in the accelerometer signal, and (iii) change the value of the distance estimate signal by a predetermined quantum only upon detection of the human step, the change being positive or negative depending on a direction of the TOF distance signal relative to the distance estimate signal.

Patent no. 9,171,985 introduces a  pixel circuit which includes a single photon avalanche diode (SPAD) and a measurement circuit including a capacitance. The SPAD detects an incident photon and the measurement circuit discharges the capacitance at a known rate during a discharge time period. The length of the discharge time period is determined by the time of detection of the photon, such that the final amount of charge on the capacitance corresponds to the time of flight of the photon. The pixel circuit may be included in a time resolved imaging apparatus. A method of measuring the time of flight of a photon includes responding to an incident photon detection by discharging a capacitance at a known rate and correlating final capacitance charge to time of flight.

If you have an interesting patent to share when we next feature patents related to time of flight technology, or if you are especially interested in a signal processing research field that you would like to highlight in this section, please send email to Csaba Benedek (benedek.csaba AT sztaki DOT mta DOT hu).

References

Number: 9,270,319
Title: Mobile device utilizing time of flight for personal security and localization
Inventors:  Bietz; Steven Lee (Cumming, GA), Acosta-Cazaubon; Jesus (Rochester, NY)
Issued:  February 23, 2016
Assignee: Voll, Inc. (Cypress, TX)

Number: 9,261,580
Title: System and method for channel information exchange for time of flight range determination
Inventors: Banin; Leor (Petach Tikva, IL), Amizur; Yuval (Kfar-Saba, IL), Schatzberg; Uri (kiryat ono, IL)
Issued:  February 16, 2016
Assignee: Intel Corporation (Santa Clara, CA)

Number: 9,241,678
Title: Random estimation in positron emission tomography with tangential time-of-flight mask
Inventors: Niu; Xiaofeng (Mundelein, IL), Wang; Wenli (Briarcliff Manor, NY)
Issued:  January 26, 2016
Assignee: Kabushiki Kaisha Toshiba (Tokyo, JP), Toshiba Medical Systems Corporation (Otawara-shi, JP)

Number: 9,234,782
Title: Volume dimensioning system and method employing time-of-flight camera
Inventors: Laffargue; Franck (Toulouse, FR), Gillet; Alain (Toulouse, FR), Thuries; Serge (Saint Jean, FR)
Issued:  January 12, 2016
Assignee: Intermec IP Corporation (Fort Mill, SC)

Number: 9,232,357
Title: 3D location based on wireless time of flight calculation
Inventors:  Buchheim; James (Aventura, FL), Hennig; Arne (Davie, FL)
Issued:  January 5, 2016
Assignee: GPB HOLDINGS II, LP (Ny, NY)

Number: 9,229,096
Title: Time-of-flight imaging systems
Inventors: Kim; Dongsoo (San Jose, CA), Lim; Jae Eun (Boise, ID), Cho; Kwangbo (San Jose, CA)
Issued:  January 5, 2016
Assignee: Semiconductor Components Industries, LLC (Phoenix, AZ)

Number: 9,220,078
Title: Mobile device utilizing time of flight for localization
Inventors: Bietz; Steven Lee (Cumming, GA), Acosta-Cazaubon; Jesus (Rochester, NY)
Issued:  December 22, 2015
Assignee: Voll, Inc. (Cumming, GA)

Number: 9,218,949
Title: Strategic dynamic range control for time-of-flight mass spectrometry
Inventors: Tanner; Scott D. (Aurora, CA)
Issued:  December 22, 2015
Assignee: Fluidigm Canada, Inc. (Markham, CA)

Number: 9,194,943
Title: Step filter for estimating distance in a time-of-flight ranging system
Inventors: Hassan; Hasib (Belleville, MI), Benton; Dale R. (Davison, MI), Lu; John (Grand Blanc, MI), Gorman; Brian A. (Burton, MI)
Issued:  November 24, 2015
Assignee: MAGNA ELECTRONICS INC. (Holland, MI)

Number: 9,171,985
Title: Pixel circuit with controlled capacitor discharge time of flight measurement
Inventors: Dutton; Neale (Edinburgh, GB), Henderson; Robert K. (Edinburgh, GB)
Issued:  October 27, 2015
Assignee: STMicroelectronics (Research & Development) Limited (Marlow, Buckinghamshire, GB)