Abstract: Indirect time-of-flight camera systems for operating in multiple optical channels using active modulated light and accompanying methods of operation are provided. In one aspect, the indirect time-of-flight camera system includes first and second modulatable laser sources outputting light of different wavelengths for illuminating a target environment. The camera system further includes a wavelength-selective reflective element designed to reflect the light of a first wavelength and to transmit the light of a second wavelength. The camera system further includes a controller comprising instructions executable to control the camera system to, in a first time period, activate the first modulatable laser source and deactivate the second modulatable laser source, and in a second time period, deactivate the first modulatable laser source and activate the second modulatable laser source.

Abstract: An image sensor is disclosed. The image sensor includes a photo detector and a readout structure electronically coupled to the photodetector. The photodetector is configured to accumulate one or more photo charges responsive to one or more incident photons during an integration period. The readout structure is configured to repeatedly and nondestructively assess an amount of minority carrier photo charges accumulated at the photodetector during the integration period.

Abstract: An image sensor comprises an array of sensor elements, each responsive to incident photon flux, and a readout circuit coupled electronically to the array of sensor elements and configured to release an electronic signal varying in dependence on the incident photon flux. A thermal-barrier zone separates the array of sensor elements from the readout circuit, and a solid-state cooler is coupled thermally to the array of sensor elements.

Abstract: Examples are disclosed that relate to the use of an always-depleted photodiode in a ToF depth image sensor. One example provides a method of operating a pixel of a depth image sensor, the method comprising receiving photons in a photocharge generation region of the pixel, the photocharge generation region of the pixel comprising an always-depleted photodiode formed by a doped first region comprising one of p-doping or n-doping and a more lightly-doped second region comprising the other of p-doping or n-doping. The method further comprises, during an integration phase, energizing a clock gate for a pixel tap, thereby directing photocharge generated in the photocharge generation region to an in-pixel storage comprising a capacitor, and in a readout phase, reading charge out from the in-pixel storage.

Abstract: An imaging method includes acquiring one or more passive light images of a scene. A region of interest in the scene is identified based on the one or more passive light images. One or more illumination zones of a plurality of illumination zones that collectively cover the region of interest is determined. Each illumination zone is sized according to active illumination emitted from a steerable illumination source. For a determined illumination zone of the one or more illumination zones, the illumination zone is individually illuminated with the active illumination from the steerable illumination source. For a pixel of a sensor array that maps to the illumination zone, a depth value of an object locus in the scene reflecting the active illumination back to the pixel is determined.

Abstract: An example imaging sensor comprises a bulk silicon substrate and a pixel array. The pixel array comprises an active pixel region including an active pixel subarray, an optical black pixel region including an optical black pixel subarray, and an optical black dummy pixel region including an optical black dummy pixel subarray, the optical black dummy pixel region positioned between the active pixel region and the optical black pixel region. A near-infrared absorber is positioned between the active pixel region and the optical black pixel region, the near-infrared absorber comprising a material having a higher near-infrared absorption coefficient than that of silicon.

Abstract: Examples are disclosed that relate to the use of an always-depleted photodiode in a ToF depth image sensor. One example provides a method of operating a pixel of a depth image sensor, the method comprising receiving photons in a photocharge generation region of the pixel, the photocharge generation region of the pixel comprising an always-depleted photodiode formed by a doped first region comprising one of p-doping or n-doping and a more lightly-doped second region comprising the other of p-doping or n-doping. The method further comprises, during an integration phase, energizing a clock gate for a pixel tap, thereby directing photocharge generated in the photocharge generation region to an in-pixel storage comprising a capacitor, and in a readout phase, reading charge out from the in-pixel storage.

Abstract: An imaging system includes a sensor array of differential pixels. A controller operates a first differential pixel of the sensor array in a first, lower power mode. The controller supplies a first clock signal to selectively activate a first collection terminal of the first differential pixel for a first duration, and a second clock signal to selectively activate a second collection terminal of the first differential pixel for a second duration. In an analog domain, a first amount of charge accumulated at the first collection terminal over the first duration is readout and compared to a readout of a second amount of charge accumulated at the second collection terminal over the second duration. Responsive to the first amount of charge being different from the second amount of charge by more than a threshold, the first differential pixel of the sensor array is operated in a second, higher power mode.

Abstract: An imaging method includes acquiring one or more passive light images of a scene. A region of interest in the scene is identified based on the one or more passive light images. One or more illumination zones of a plurality of illumination zones that collectively cover the region of interest is determined. Each illumination zone is sized according to active illumination emitted from a steerable illumination source. For a determined illumination zone of the one or more illumination zones, the illumination zone is individually illuminated with the active illumination from the steerable illumination source. For a pixel of a sensor array that maps to the illumination zone, a depth value of an object locus in the scene reflecting the active illumination back to the pixel is determined.

Abstract: A camera includes one or more spectral illuminators, a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, and a sensor array. The one or more spectral illuminators are configured to emit active spectral light. The tunable optical filter is dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene. The sensor array includes a plurality of sensors each configured to measure spectral light reflected from the scene in the selected sub-band.

Abstract: An optical filter for a camera is switchable between a reflection state and a transmission state. The optical filter includes a first plurality of liquid crystals configured to dynamically form cholesteric phase structures in the reflection state that block right-handed circularly polarized light in a spectral light sub-band and transmit light outside of the spectral light sub-band. The first plurality of liquid crystals dynamically forms a nematic phase arrangement in the transmission state that transmits light in the spectral light sub-band. The optical filter further includes a second plurality of liquid crystals configured to dynamically form cholesteric phase structures in the reflection state that block left-handed circularly polarized light in the spectral light sub-band and transmit light outside of the spectral light sub-band. The second plurality of liquid crystals dynamically form a nematic phase arrangement in the transmission state that transmits light in the spectral light sub-band.

Abstract: A camera includes one or more spectral illuminators, a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, and a sensor array. The one or more spectral illuminators are configured to emit active spectral light. The tunable optical filter is dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene. The sensor array includes a plurality of sensors each configured to measure spectral light reflected from the scene in the selected sub-band.

Abstract: A camera includes a time-of-flight illuminator configured to emit active IR light and a plurality of spectral illuminators, each spectral illuminator configured to emit active spectral light in a different spectral light sub-band. The camera further includes a sensor array that includes a plurality of differential sensors. Each differential sensor is configured to differentially measure both 1) the active IR light, and 2) the active spectral light in each of the different spectral light sub-bands. The camera further includes an output machine operatively connected to the sensor array. The output machine is configured to output a matrix of pixels based on time-multiplexed measurements of the sensor array. Each pixel of the matrix includes 1) a depth value, and 2) a plurality of spectral values. Each of the plurality of spectral values corresponds to a spectral light sub-band of one of the plurality of spectral illuminators.

Abstract: An imaging sensor array comprises an epitaxial germanium layer disposed on a silicon layer, and an electrically biased photoelectron collector arranged on the silicon layer, on a side opposite the germanium layer.

Abstract: An active illumination range camera comprising illumination and imaging systems that is operable to provide a range image of a scene in the imaging system's field of view (FOV) by partitioning the range camera FOV into sub-FOVs, and controlling the illumination and imaging systems to sequentially illuminate and image portions of the scene located in the respective sub-FOVs.

Abstract: Pixel arrangements in time-of-flight sensors are presented that include sensing elements that establish charges related to incident light, charge storage elements that accumulate integrated charges transferred from the sensing elements, and diffusion nodes configured to establish measurement voltages representative of the integrated charges that are dumped from the charge storage elements. The pixel arrangement includes analog domain output circuitry comprising a measurement capacitance element that stores the measurement voltage, and a reset capacitance element that stores a reset voltage established at the diffusion node during a reset phase performed prior to a measurement phase. The analog domain output circuitry subtracts the stored reset voltage from the stored measurement voltage for processing into a pixel output voltage that at least partially reduces readout voltage uncertainty of the pixel arrangement.

Abstract: A camera includes one or more spectral illuminators, a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, and a sensor array. The one or more spectral illuminators are configured to emit active spectral light. The tunable optical filter is dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene. The sensor array includes a plurality of sensors each configured to measure spectral light reflected from the scene in the selected sub-band.

Abstract: A camera includes one or more spectral illuminators, a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, and a sensor array. The one or more spectral illuminators are configured to emit active spectral light. The tunable optical filter is dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene. The sensor array includes a plurality of sensors each configured to measure spectral light reflected from the scene in the selected sub-band.

Abstract: Pixel arrangements in time-of-flight sensors or other imaging sensors are presented that include a sensing element configured to accumulate charges related to incident light, and two transfer gates proximate to the sensing element and configured to selectively control transfer of the charges in the pixel arrangement. During an integration phase, a charge storage element for a global shutter stores first charges received from the sensing element based on activation of a first transfer gate and inactivation of a second transfer gate. During a reset phase, a diffusion node receives second charges received from the sensing element based on inactivation of the first transfer gate and activation of the second transfer gate. During a pixel readout phase, the diffusion node receives the first charges received from the charge storage element based on activation of the first transfer gate and activation of the second transfer gate.

Abstract: An active illumination range camera comprising illumination and imaging systems that is operable to provide a range image of a scene in the imaging system's field of view (FOV) by partitioning the range camera FOV into sub-FOVs, and controlling the illumination and imaging systems to sequentially illuminate and image portions of the scene located in the respective sub-FOVs.