Abstract: Imaging apparatus includes a camera, which includes an autofocus mechanism. A range sensor includes a transmitter, which includes multiple emitters configured to transmit optical pulses at different angles toward the scene, and a receiver, to receive and sense respective times of flight of the optical pulses that are reflected from the scene. A photodetector outputs a signal indicative of an intensity of reflections from the scene. Control circuitry drives the emitters in alternation to transmit the optical pulses, estimates a range to a target in the scene responsively to the times of flight sensed by the receiver, detects a difference in the signal output by the photodetector in response to the pulses transmitted by different ones of the emitters, and sets the autofocus mechanism responsively to the estimated range as long as the detected difference is no greater than a predefined threshold difference.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

Abstract: Depth sensing apparatus includes a radiation source, which emits a first array of beams of light pulses through a window toward a target scene. Objective optics image the target scene onto a second array of sensing elements, which output signals indicative of respective times of incidence of photons. A first calibration, which associates the beams in the first array with respective first locations on the second array onto which the beams reflected from the target scene are imaged, is used in processing the signals in order to measure respective times of flight of the light pulses. A second calibration indicates second locations on which stray radiation is incident on the second array due to reflection of the beams from the window. Upon detecting a change in the second locations relative to the second calibration, the first calibration is corrected so as to compensate for the detected change.

Abstract: Imaging apparatus includes a camera, which includes an autofocus mechanism. A range sensor includes a transmitter, which includes multiple emitters configured to transmit optical pulses at different angles toward the scene, and a receiver, to receive and sense respective times of flight of the optical pulses that are reflected from the scene. A photodetector outputs a signal indicative of an intensity of reflections from the scene. Control circuitry drives the emitters in alternation to transmit the optical pulses, estimates a range to a target in the scene responsively to the times of flight sensed by the receiver, detects a difference in the signal output by the photodetector in response to the pulses transmitted by different ones of the emitters, and sets the autofocus mechanism responsively to the estimated range as long as the detected difference is no greater than a predefined threshold difference.

Abstract: Imaging apparatus (22) includes a radiation source (40), which emits pulsed beams (42) of optical radiation toward a target scene (24). An array (52) of sensing elements outputs signals indicative of respective times of incidence of photons on the sensing elements. Objective optics (54) form a first image of the target scene on the array of sensing elements. An image sensor (64) captures a second image of the target scene. Processing and control circuitry (56, 58) is configured to process the second image so as to detect a relative motion between at least one object in the target scene and the apparatus, and which is configured to construct, responsively to the signals from the array, histograms of the times of incidence of the photons on the sensing elements and to adjust the histograms responsively to the detected relative motion, and to generate a depth map of the target scene based on the adjusted histograms.

Abstract: Various embodiments disclosed herein include techniques for determining autofocus for a camera on a mobile device. In various instances, a depth imaging system (e.g., a time-of-flight autofocus system (ToF-AF system)) is used to determine distance of a subject in order to determine autofocus for a camera. In some instances, however, the ToF-AF system may be unable to detect a subject that is very close to the camera when the objects are below a minimum detectable distance of the ToF-AF system. In such instances, an existing IR detector outside of the ToF-AF system may be implemented to measure reflected signals from the ToF-AF system. A power ratio may be determined from the reflected signals and used to determine information about the distance of the subject from the camera.

Abstract: Techniques are disclosed relating to biometric authentication, e.g., facial recognition. In some embodiments, a device is configured to verify that image data from a camera unit exhibits a pseudo-random sequence of image capture modes and/or a probing pattern of illumination points (e.g., from lasers in a depth capture mode) before authenticating a user based on recognizing a face in the image data. In some embodiments, a secure circuit may control verification of the sequence and/or the probing pattern. In some embodiments, the secure circuit may verify frame numbers, signatures, and/or nonce values for captured image information. In some embodiments, a device may implement one or more lockout procedures in response to biometric authentication failures. The disclosed techniques may reduce or eliminate the effectiveness of spoofing and/or replay attacks, in some embodiments.

Abstract: Imaging apparatus (22) includes a radiation source (40), which emits pulsed beams (42) of optical radiation toward a target scene (24). An array (52) of sensing elements (78) output signals indicative of respective times of incidence of photons in a first image of the target scene that is formed on the array of sensing elements. An image sensor (64) captures a second image of the target scene in registration with the first image. Processing and control circuitry (56, 58) identifies, responsively to the signals, areas of the array on which the pulses of optical radiation reflected from corresponding regions of the target scene are incident, and processes the signals from the sensing elements in the identified areas in order measure depth coordinates of the corresponding regions of the target scene based on the times of incidence, while identifying, responsively to the second image, one or more of the regions of the target scene as no-depth regions.

Abstract: Techniques are disclosed relating to biometric authentication, e.g., facial recognition. In some embodiments, a device is configured to verify that image data from a camera unit exhibits a pseudo-random sequence of image capture modes and/or a probing pattern of illumination points (e.g., from lasers in a depth capture mode) before authenticating a user based on recognizing a face in the image data. In some embodiments, a secure circuit may control verification of the sequence and/or the probing pattern. In some embodiments, the secure circuit may verify frame numbers, signatures, and/or nonce values for captured image information. In some embodiments, a device may implement one or more lockout procedures in response to biometric authentication failures. The disclosed techniques may reduce or eliminate the effectiveness of spoofing and/or replay attacks, in some embodiments.

Abstract: Various embodiments disclosed herein include techniques for determining autofocus for a camera on a mobile device. In some instances, depth imaging is used to assist in determining a focus position for the camera through an autofocus process. For example, a determination of depth may be used to determine a focus position for the camera. In another example, the determination of depth may be used to assist another autofocus process.

Abstract: An optical sensing device includes a light source, which emits one or more beams of light pulses toward a target scene at respective angles about a transmit axis of the light source. A first array of single-photon detectors output electrical pulses in response to photons that are incident thereon. A second array of counters count the electrical pulses output during respective count periods by respective sets of one or more of the single-photon detectors. Light collection optics form an image of the target scene on the first array along a receive axis, which is offset transversely relative to the transmit axis, thereby giving rise to a parallax shift as a function of distance between the target scene and the device. Control circuitry sets the respective count periods of the counters, responsively to the parallax shift, to cover different, respective time intervals following each of the light pulses.

Abstract: Various embodiments disclosed herein include techniques for determining autofocus for a camera on a mobile device. In some instances, depth imaging is used to assist in determining a focus position for the camera through an autofocus process. For example, a determination of depth may be used to determine a focus position for the camera. In another example, the determination of depth may be used to assist another autofocus process.

Abstract: An optical sensing device includes a light source, which emits one or more beams of light pulses toward a scene. An array of single-photon detectors output electrical pulses in response to photons that are incident thereon. Light collection optics form an image of the scene on the array. Processing circuitry counts the electrical pulses output by the single-photon detectors during multiple time intervals following each of the light pulses, detects, responsively to the counted pulses, an object located less than 10 cm away from the array, makes a comparison between respective counts of the electrical pulses output by the single-photon detectors group during a specified time interval immediately following each of a plurality of the light pulses, and ascertains, responsively to the comparison, whether the object reflecting the at least one of the beams is fixed to the device or separate from the device.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

Abstract: An optical sensing device includes a light source, which emits one or more beams of light pulses toward a target scene at respective angles about a transmit axis of the light source. A first array of single-photon detectors output electrical pulses in response to photons that are incident thereon. A second array of counters count the electrical pulses output during respective count periods by respective sets of one or more of the single-photon detectors. Light collection optics form an image of the target scene on the first array along a receive axis, which is offset transversely relative to the transmit axis, thereby giving rise to a parallax shift as a function of distance between the target scene and the device. Control circuitry sets the respective count periods of the counters, responsively to the parallax shift, to cover different, respective time intervals following each of the light pulses.

Abstract: Various embodiments disclosed herein include techniques for determining autofocus for a camera on a mobile device. In some instances, depth imaging is used to assist in determining a focus position for the camera through an autofocus process. For example, a determination of depth may be used to determine a focus position for the camera. In another example, the determination of depth may be used to assist another autofocus process.

Abstract: Depth mapping apparatus includes an illumination assembly, which directs modulated optical radiation toward a target scene, and a camera, which captures a two-dimensional image of the target scene. A range sensor senses respective times of flight of photons reflected from a matrix of locations disposed across the target scene. A processor derives first depth coordinates of the matrix of locations responsively to the respective times of flight, derives second depth coordinates of the matrix of locations responsively to a transverse disparity between features in the two-dimensional image and corresponding reference features in a reference image, computes a disparity correction function based on a difference between the first and the second depth coordinates at the matrix of locations, corrects the transverse disparity between the two-dimensional image and the reference image using the disparity correction function, and generates a depth map of the target scene based on the corrected transverse disparity.

Abstract: Sensing apparatus includes a radiation source, which emits pulses of optical radiation toward multiple points in a target scene. A receiver receives the optical radiation that is reflected from the target scene and outputs signals that are indicative of respective times of flight of the pulses to and from the points in the target scene. Processing and control circuitry selects a first pulse repetition interval (PRI) and a second PRI, greater than the first PRI, from a permitted range of PRIs, drives the radiation source to emit a first sequence of the pulses at the first PRI and a second sequence of the pulses at a second PRI, and processes the signals output in response to both the first and second sequences of the pulses in order to compute respective depth coordinates of the points in the target scene.

Abstract: Sensing apparatus includes a radiation source, which emits pulses of optical radiation toward multiple points in a target scene. A receiver receives the optical radiation that is reflected from the target scene and outputs signals that are indicative of respective times of flight of the pulses to and from the points in the target scene. Processing and control circuitry selects a first pulse repetition interval (PRI), a second PRI, greater than the first PRI, and a third PRI, greater than the second PRI, from a permitted range of PRIs, drives the radiation source to emit sequences of the pulses at the first PRI, the second PRI, and the third PRI, and processes the signals output by the receiver in response to the first, second, and third sequences of the pulses in order to compute respective depth coordinates of the points in the target scene.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.