1681 results about "Backscatter" patented technology

An RFID system includes a hybrid backscatter-based RFID tag protocol-compatible with existing 802.11x / Bluetooth Standards as well as RFID standards. The tag is linked to a multi-protocol Interrogator via a generated RF Continuous Wave (CW) field. The tag includes an antenna coupled to an RFID and a Bluetooth / 802.11x transceiver section. A Protocol Processor services RFID and transceiver sections and is coupled to the antenna via a backscatter switch. The Interrogator can switch the tag to an RFID backscatter radiation mode where the processor switches the antenna impedance to reflect the CW signal. For transceiver operation the processor switches antenna impedance in synchronization with a frame organized bit stream. For reception, the RFID section utilizes demodulation techniques, typically Amplitude Shift Keying (ASK), and provides a wake up mode within a predetermined distance of the Interrogator. The transceiver may operate in a backscatter or regular mode as directed by an Access Point.

A method for tomographic imaging comprises the steps of providing a source of at least partially coherent radiation and a frequency-swept laser source through an interferometer; phase modulating the radiation in the interferometer at a modulation frequency for elimination of DC and autocorrelation noises as well as the mirror image; detecting interference fringes of the radiation backscattered from the sample into the interferometer to obtain a spectral signal; transforming the spectral signal of the detected backscattered interference fringes to obtain a time and location dependent signal, including the Doppler shift and variance, at each pixel location in a data window; and generating a tomographic image of the fluid flow in the data window and of the structure of the scanned fluid flow sample in the data window from the time and location dependent signal. The apparatus comprises a system for tomographic imaging operating according to the above method.

Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.

An optical manifold for efficiently combining a plurality of LED outputs into a single, substantially homogeneous output, in a small, cost-effective package. The optical manifolds can be used to combine multiple LEDs of the same color and provide a high intensity output aperture with very high uniformity and sharp borders, or they can be used to generate a multiwavelength output, such as red, green, and blue LEDs that are combined to generate white light. Embodiments are also disclosed that use a single or multiple LEDs and a remote phosphor and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. The optical manifolds are designed to alleviate substantial luminance inhomogeneities inherent to LEDs. The optical manifold utilizes principles of non-imaging optics to transform light and provide directed, substantially uniform light sources.

A method and apparatus is disclosed herein for real-time wireless power transfer control. In one embodiment, a system comprises: an RF-energy harvesting sensor tag operable to generate a first backscatter signal and at least one base station operable to deliver RF power to the sensor tag by emitting a first waveform comprising a plurality of subcarriers, wherein the first backscatter signal is generated by the sensor tag by modulated scattering of the first waveform as incident upon the sensor tag, and further wherein the at least one base station subsequently emits a second waveform determined at least in part by a closed-loop feedback control algorithm responsive to measurements of the first backscatter signal.

An RFID transponder is provided with an active backscatter amplifier that amplifies and re-transmits a received signal. The RFID transponder comprises an antenna and a circulator having a first port connected to the antenna. A modulator is connected to a second port of the circulator. An amplifier is connected to a third port of the circulator, with the amplifier connected to the modulator. An RF signal impinging upon the antenna passes through the circulator, the amplifier, and the modulator, and returns to the antenna through the circulator. The modulator further comprises an input coupled to the second port of the circulator and an output coupled to an input of the amplifier. The amplifier has an output coupled to the third port of the circulator. The modulator is adapted to modulate the RF signal using on-off keying.

Optical coherence tomography with 3D coherence scanning is disclosed, using at least three fibers (201, 202, 203) for object illumination and collection of backscattered light. Fiber tips (1, 2, 3) are located in a fiber tip plane (71) normal to the optical axis (72). Light beams emerging from the fibers overlap at an object (122) plane, a subset of intersections of the beams with the plane defining field of view (266) of the optical coherence tomography apparatus. Interference of light emitted and collected by the fibers creates a 3D fringe pattern. The 3D fringe pattern is scanned dynamically over the object by phase shift delays (102, 104) controlled remotely, near ends of the fibers opposite the tips of the fibers, and combined with light modulation. The dynamic fringe pattern is backscattered by the object, transmitted to a light processing system (108) such as a photo detector, and produces an AC signal on the output of the light processing system (108). Phase demodulation of the AC signal at selected frequencies and signal processing produce a measurement of a 3D profile of the object.

An RFID integrated circuit includes a demodulator to receive a first signal, the first signal having been generated by an RFID reader responsive to detection of a first environmental condition. The RFID integrated circuit further includes a controller to set, based on the first signal, a modulation format for the RFID integrated circuit and to configure the RFID integrated circuit to modulate a backscatter signal according to the modulation format.

A method and apparatus for determining properties of a tissue or tissues imaged by optical coherence tomography (OCT). In one embodiment the backscatter and attenuation of the OCT optical beam is measured and based on these measurements and indicium such as color is assigned for each portion of the image corresponding to the specific value of the backscatter and attenuation for that portion. The image is then displayed with the indicia and a user can then determine the tissue characteristics. In an alternative embodiment the tissue characteristics is classified automatically by a program given the combination of backscatter and attenuation values.

Systems and methods for determining ICP based on parameters that can be measured using non-invasive or minimally invasive techniques are provided, wherein a non-linear relationship is used to determine ICP based on one or more variable inputs. The first variable input relates to one or more properties of a cranial blood vessel and / or blood flow, such as acoustic backscatter from an acoustic transducer having a focus trained on a cranial blood vessel, flow velocity in a cranial blood vessel, and the like. Additional variables, such as arterial blood pressure (ABP), may be used in combination with a first variable input relating to one or more properties of a cranial blood vessel, such as flow velocity of the middle cerebral artery (MCA) to derive ICP using a non-linear relationship. Methods and systems for locating target areas based on their acoustic properties and for acoustic scanning of an area, identification of a target area of interest based on acoustic properties, and automated focusing of an acoustic source and / or detector on a desired target area are also provided. Acoustic transducer assemblies are described.

Method and system are disclosed for de-embedding optical component characteristics from optical device measurements. In particular, the invention uses frequency domain averaging of the RBS on both sides of an optical component to determine one or more of its optical characteristics. Where the RBS has a slope (e.g., as in the case of a lossy fiber), a frequency domain least square fit can be used to determine the optical component characteristics. In addition, the invention uses a reference DUT to correct for variations in the frequency response of the photoreceiver. A reference interferometer is used in the invention to correct for sweep non-linearity of the TLS. The optical component characteristics are then de-embedded from optical device measurements to provide a more precise analysis of the optical device.

An integrated optical sensor, using low coherence interferometry, is capable of determining analyte concentration in a material sample based on absorption, scattering and polarization. The sensor includes one or more light collectors, with each collector having a separation distance from the region where the sample is illuminated by the source. The light backscattered from the sample is combined with reference arm light at the same optical path length for each light collector. The intensity of interference may be correlated with the concentration of an analyte in the material, for example the glucose concentration in a turbid medium like skin. The sensor operation can be based on fiber optics technology, integrated optics, or a combination of these. The operation is such that the spectrally resolved scattering and absorption coefficients can be measured simultaneously. In addition, the operation of the sensor can be synchronized with other sensors, for example temperature, pressure, or heartrate.

In part, the invention relates to optical caps having at least one lensed surface configured to redirect and focus light outside of the cap. The cap is placed over an optical fiber. Optical radiation travels through the fiber and interacts with the optical surface or optical surfaces of the cap, resulting in a beam that is either focused at a distance outside of the cap or substantially collimated. The optical elements such as the elongate caps described herein can be used with various data collection modalities such optical coherence tomography. In part, the invention relates to a lens assembly that includes a micro-lens; a beam director in optical communication with the micro-lens; and a substantially transparent film or cover. The substantially transparent film is capable of bi-directionally transmitting light, and generating a controlled amount of backscatter. The film can surround a portion of the beam director.

A system for treating a selected dermatologic problem and a head for use with such system are provided. The head may include an optical waveguide having a first end to which EM radiation appropriate for treating the condition is applied. The waveguide also has a skin-contacting second end opposite the first end, a temperature sensor being located within a few millimeters, and preferably within 1 to 2 millimeters, of the second end of the waveguide. A temperature sensor may be similarly located in other skin contacting portions of the head. A mechanism is preferably also provided for removing heat from the waveguide and, for preferred embodiments, the second end of the head which is in contact with the skin has a reflection aperture which is substantially as great as the radiation back-scatter aperture from the patient's skin. Such aperture may be the aperture at the second end of the waveguide or a reflection plate or surface of appropriate size may surround the waveguide or other light path at its second end. The portion of the back-scattered radiation entering the waveguide is substantially internally reflected therein, with a reflector being provided, preferably at the first end of the waveguide, for returning back-scattered light to the patient's skin. The reflector may be angle dependent so as to more strongly reflect back scattered light more perpendicular to the skin surface than back scattered radiation more parallel to the skin surface. Controls are also provided responsive to the temperature sensing for determining temperature at a predetermined depth in the patient's skin, for example at the DE junction, and for utilizing this information to detect good thermal contact between the head and the patient's skin and to otherwise control treatment. The head may also have a mechanism for forming a reflecting chamber under the waveguide and drawing a fold of skin therein, or for providing a second enlarged waveguide to expand the optical aperture of the radiation.

A system and method is provided for locating objects using RFID tags. The system and method uses an RFID reader and a distance calculator to efficiently and accurately determine the location of objects that include an RFID tag. The RFID reader transmits a plurality of signals to the RFID tag, with the plurality of signals having different fundamental frequencies. In response, the RFID tag backscatter modulates the plurality of transmitted signals to create a plurality of backscatter modulated signals. The RFID reader receives and demodulates the plurality of backscatter modulated signals. The distance calculator determines the phase of the plurality of backscatter modulated signals and determines a rate of change of the phase in the backscatter modulated signals with respect to the rate of change in the fundamental frequency of the transmitted signals and uses this information to calculate the distance to the RFID tag.

A method and apparatus for determining a pose of an elongate object and an absolute position of its tip while the tip is in contact with a plane surface having invariant features. The surface and features are illuminated with a probe radiation and a scattered portion, e.g., the back-scattered portion, of the probe radiation returning from the plane surface and the feature to the elongate object at an angle τ with respect to an axis of the object is detected. The pose is derived from a response of the scattered portion to the surface and the features and the absolute position of the tip on the surface is obtained from the pose and knowledge about the feature. The probe radiation can be directed from the object to the surface at an angle σ to the axis of the object in the form of a scan beam. The scan beam can be made to follow a scan pattern with the aid of a scanning arrangement with one or more arms and one or more uniaxial or biaxial scanners. Angle τ can also be varied, e.g., with the aid of a separate or the same scanning arrangement as used to direct probe radiation to the surface. The object can be a pointer, a robotic arm, a cane or a jotting implement such as a pen, and the features can be edges, micro-structure or macro-structure belonging to, deposited on or attached to the surface which the tip of the object is contacting.

Distance to a modulated backscatter tag is measured with a RFID reader that measures changes in phase with frequency of modulated backscattered RF signals. Measured distances are linked to a specific tag. The effects of other sources of reflected and interfering signals are mitigated. The techniques eliminate the need for high RF bandwidth used in time-of-flight methods, and may be used with linear, limiting or other types of amplifiers in the reader receiver. Unambiguous distance to a tag may be found using the derivative of phase with RF frequency of the modulated signal backscattered by a tag. The distance to a tag can be measured with an accuracy on the order of a centimeter. The techniques utilize the characteristics of cooperative backscatter tags (transponders, labels, etc.). New readers implement the techniques which may use unmodified tags.

A method and system is provided for using backscattered data and known parameters to characterize vascular tissue. Specifically, methods and devices for identifying information about the imaging element used to gather the backscattered data are provided in order to permit an operation console having a plurality of Virtual Histology classification trees to select the appropriate VH classification tree for analyzing data gathered using that imaging element. In order to select the appropriate VH database for analyzing data from a specific imaging catheter, it is advantageous to know information regarding the function and performance of the catheter, such as the operating frequency of the catheter and whether it is a rotational or phased-array catheter. The present invention provides a device and method for storing this information on the imaging catheter and communicating the information to the operation console. In addition, information related to additional functions of the catheter may also be stored on the catheter and used to further optimize catheter performance and / or select the appropriate Virtual Histology classification tree for analyzing data from the catheter imaging element.

Methods and apparatus are provided to locate a terminal within a workspace. Radio frequency identification (RFID) tags are provided in known locations, preferably in, on or adjacent the light fixtures or other workspace infrastructure. The terminal comprises an RFID tag interrogation transceiver, processor and memory. The transceiver interrogates the tags which respond with information correlatable with their unique locations. The terminal determines its locations relative to the known locations of responding tags by, for example, varying its transmit power and / or receiver sensitivity and / or by trilateration using, for example, phase or time difference of arrival measurements on the tag response signals. Once it has determined its own location it may transmit or otherwise announce its location as desired by the user. In a preferred embodiment, the natural electromagnetic radiation and / or RADAR cross section backscatter from fluorescent type fixtures, modulated with their position information, acts as the RFID infrastructure beacon.

An optical manifold for efficiently combining a plurality of blue LED outputs to illuminate a phosphor for a single, substantially homogeneous output, in a small, cost-effective package. Embodiments are disclosed that use a single or multiple LEDs and a remote phosphor, and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. A further aperture mask is used to boost phosphor luminance with only modest loss of luminosity. Alternative non-recycling embodiments provide blue and yellow light in collimated beams, either separately or combined into white.

Systems, methods and devices are provided for detecting airborne particulates and / or gases at remote oil and natural gas sites, such as wells, and / or processing and refinery plants. One such system comprises an unmanned aerial vehicle (UAV), such as a drone aircraft, configured for aerial dispatch to the remote site and wireless connection to an external processor, cloud apparatus or the like. The UAV includes one or more on-board sensors configured to detect airborne particulates or gases, such as methane gas, hydrogen sulfide, hydrocarbons, weather conditions, ground-based elements or compounds or the like. The on-board sensors may comprise light transmitters, such as lasers, configured for transmitting light or laser pulses into the ambient environment around the remote site and detecting backscatter to detect the concentration and / or velocity vector(s) of the airborne particulates or gases. The UAV is further configured to wirelessly transmit data associated with the airborne particulates or gases to the external processor or cloud apparatus in real-time.

A radio frequency identification (RFID) architecture is described. RFID tags are interrogated by a reader, which may be located in a network of readers. The reader transmits symbols to the tags. Tags respond to the interrogations with symbols that each represent one or more bits of data. An RFID tag includes an antenna pad, a receiver, a state machine, and a modulator. The receiver is coupled to the antenna pad. The receiver receives a symbol from the antenna pad and outputs a received signal. The state machine is configured to determine a response symbol from the received signal and an operating state of the tag. The modulator is coupled to the antenna pad. The modulator is configured to backscatter modulate the received symbol with the response symbol. The modulator is configured to output the backscatter modulated symbol to the antenna pad.

An in-vivo device may include an optical system, and a method for viewing in-vivo sites. A dome or cover may cover an end of the device, protecting optical elements such as illumination devices or imagers, which may be behind the dome. The dome may be forward projecting and may have a convex shape. The field of view of the imager may be for example forward looking. Illumination element(s) and a receiving unit or imager may be disposed behind a single optical window, which for example may enable obtaining of images free of backscatter and stray light. The convex shape of the dome may be defined such that it may have a shape having an isolated area. At least one illumination element and at least one receiving unit may be geometrically positioned (for example in the isolated area) such that rays from the illumination elements, some of which are internally reflected from the internal and / or external surface of the optical window, will not be incident on the receiving unit.

An RFID tag has an antenna to receive a configuration signal, and a circuit with a controller that can configure the RFID circuit responsive to the configuration signal. Configuring is such that the tag backscatters by impressing data either on the carrier frequency, or on a subcarrier in addition to the carrier signal, depending on the configuration signal. In the event of a subcarrier, the tag controller may optionally further determine a frequency of the subcarrier from the configuration signal. The tag may then be configured to backscatter differently, upon receiving a different configuration signal. A complementary reader transmits the configuration signal, thus imparting an operating parameter. The reader has an interface to receive an input indicative of a present geography, and a lookup table for determining an operating parameter based on the present geography. In one embodiment, the operating parameter is determined from regulations at that geographic location.