Abstract: One example provides a method of operating a time-of-flight camera system comprising an illumination source and an image sensor. The method comprises operating the illumination source and the image sensor to control a plurality of integration cycles and a plurality of readout cycles. In each integration cycle, the method comprises performing a plurality of pulse width modulated (PWM) illumination cycles where each PWM illumination cycle is separated from one or more adjacent PWM illumination cycles by a non-illumination cycle. For each PWM illumination cycle, the method comprises directing photocharge to in-pixel memory for each pixel that is performing image integration and for each non-illumination cycle conducting photocharge away from the in-pixel memory for each pixel that is performing image integration. The readout cycle comprises, for each pixel that performed image integration, reading a charge stored in the in-pixel memory after the integration cycle.

Abstract: Examples are disclosed herein that relate to a time-of-flight camera that performs phase unwrapping in an efficient manner. In one example, a time-of-flight camera includes a light emitter, a sensor array, and a controller. The controller is configured to select a frequency mode from a plurality of frequency modes, each frequency mode including two or more different frequencies, and at least two different frequency modes of the plurality of frequency modes having a common frequency shared between the at least two frequency modes, control the light emitter to illuminate a scene with modulated light of the two or more different frequencies of the frequency mode selected, control the sensor array to receive the modulated light reflected from objects within the scene, and process the modulated light received to determine unwrapped phases for the frequency mode selected based on the two or more different frequencies of the frequency mode selected.

Abstract: The technology described herein recalibrates a structured light sensor in the field using time-of-flight sensor data. Structured light sensors are sensitive to mechanical changes that result in decreased accuracy. A structured light system calculates the range to an object by comparing a reference image to the actual image of the scene. The reference image is what the projected light pattern would look like on a flat object at a known distance. When the projected image changes, the reference image no longer matches the projected pattern. The calibration technology described herein captures a new reference image based on the current sensor characteristics using a time-of-flight capable sensor as the structured light imaging sensor.

Abstract: One example provides a time-of-flight depth imaging system configured to modulate light emitted from a light source to illuminate an environment with modulated light, and for each of one or more modulation frequencies, integrate an image at each phase step of a plurality of phase steps, and sense a temperature of the light source and/or image sensor via one or more temperature sensors to acquire a measured temperature. The instructions are further executable to, and for each pixel of one or more pixels of the image sensor, determine a complex phasor based upon the measured temperature using a linear inverse function for each modulation frequency, determine a phase shift between the light emitted from the light source and light from the light source reflected back by the environment based on the complex phasor, and output a depth value for the pixel based upon the phase shift.

Abstract: One example provides a method of operating a time-of-flight camera system comprising an illumination source and an image sensor. The method comprises operating the illumination source and the image sensor to control a plurality of integration cycles and a plurality of readout cycles. In each integration cycle, the method comprises performing a plurality of pulse width modulated (PWM) illumination cycles where each PWM illumination cycle is separated from one or more adjacent PWM illumination cycles by a non-illumination cycle. For each PWM illumination cycle, the method comprises directing photocharge to in-pixel memory for each pixel that is performing image integration and for each non-illumination cycle conducting photocharge away from the in-pixel memory for each pixel that is performing image integration. The readout cycle comprises, for each pixel that performed image integration, reading a charge stored in the in-pixel memory after the integration cycle.

Abstract: Examples are disclosed herein that relate to a time-of-flight camera that performs phase unwrapping in an efficient manner. In one example, a time-of-flight camera includes a light emitter, a sensor array, and a controller. The controller is configured to select a frequency mode from a plurality of frequency modes, each frequency mode including two or more different frequencies, and at least two different frequency modes of the plurality of frequency modes having a common frequency shared between the at least two frequency modes, control the light emitter to illuminate a scene with modulated light of the two or more different frequencies of the frequency mode selected, control the sensor array to receive the modulated light reflected from objects within the scene, and process the modulated light received to determine unwrapped phases for the frequency mode selected based on the two or more different frequencies of the frequency mode selected.

Abstract: One example provides a time-of-flight depth imaging system configured to modulate light emitted from a light source to illuminate an environment with modulated light, and for each of one or more modulation frequencies, integrate an image at each phase step of a plurality of phase steps, and sense a temperature of the light source and/or image sensor via one or more temperature sensors to acquire a measured temperature. The instructions are further executable to, and for each pixel of one or more pixels of the image sensor, determine a complex phasor based upon the measured temperature using a linear inverse function for each modulation frequency, determine a phase shift between the light emitted from the light source and light from the light source reflected back by the environment based on the complex phasor, and output a depth value for the pixel based upon the phase shift.

Abstract: The technology described herein recalibrates a structured light sensor in the field using time-of-flight sensor data. Structured light sensors are sensitive to mechanical changes that result in decreased accuracy. A structured light system calculates the range to an object by comparing a reference image to the actual image of the scene. The reference image is what the projected light pattern would look like on a flat object at a known distance. When the projected image changes, the reference image no longer matches the projected pattern. The calibration technology described herein captures a new reference image based on the current sensor characteristics using a time-of-flight capable sensor as the structured light imaging sensor.

Abstract: The technology described herein recalibrates a structured light sensor in the field using time-of-flight sensor data. Structured light sensors are sensitive to mechanical changes that result in decreased accuracy. A structured light system calculates the range to an object by comparing a reference image to the actual image of the scene. The reference image is what the projected light pattern would look like on a flat object at a known distance. When the projected image changes, the reference image no longer matches the projected pattern. The calibration technology described herein captures a new reference image based on the current sensor characteristics using a time-of-flight capable sensor as the structured light imaging sensor.

Abstract: The technology described herein recalibrates a structured light sensor in the field using time-of-flight sensor data. Structured light sensors are sensitive to mechanical changes that result in decreased accuracy. A structured light system calculates the range to an object by comparing a reference image to the actual image of the scene. The reference image is what the projected light pattern would look like on a flat object at a known distance. When the projected image changes, the reference image no longer matches the projected pattern. The calibration technology described herein captures a new reference image based on the current sensor characteristics using a time-of-flight capable sensor as the structured light imaging sensor.

Abstract: A method for facilitating removal of multipath signal interference from light data can comprise illuminating, with an illumination unit, a target with a light source. The illumination unit can be configured to project a high spatial-frequency pattern onto the target in such a way as to redistribute spectral energy to higher frequencies. The method can also comprise acquiring, with a sensor unit, reflected light data reflected from the target. The reflected light data can comprise an array of spatial domain information received from light reflected by the target. Further, the method can comprise processing, with the one or more processors, the reflected light data. The processing applies a high-pass filter within the spatial domain to the reflected light data.

Abstract: A method for facilitating removal of specular reflection noise from light data can include illuminating, using an illumination unit, a target with a light source. The illumination unit is configured to project light with a spatial light pattern onto the target. The method can also include acquiring, with a sensor unit, light data that is reflected from the target. The light data may comprise a directly reflected spatial light pattern and a specular reflected spatial light pattern. The directly reflected spatial light pattern and the specular reflected spatial light pattern comprise at least one spatial distinction that distinguishes the directly reflected spatial light pattern from the specular reflected spatial light pattern. The method can further comprise processing the light data to distinguish the directly reflected spatial light pattern from the specular reflected spatial light pattern based upon the at least one spatial distinction.

Abstract: A method for compensating for light reflected from non-uniform targets comprises illuminating, with an illumination unit, a target. During a first frame, the illumination unit is configured to project a uniform pattern onto the target. During a second frame, the illumination unit is configured to project a high spatial-frequency pattern onto the target in such a way as to redistribute spectral energy to higher frequencies. The method further includes acquiring, with a sensor unit, first light data reflected from the target within the first frame and second light data reflected from the target within the second frame. Further, the method includes calculating, with the one or more processors, normalized light data by dividing, within the spatial frequency domain, the second light data by the first light data.

Abstract: A method for facilitating removal of specular reflection noise from light data can include illuminating, using an illumination unit, a target with a light source. The illumination unit is configured to project light with a spatial light pattern onto the target. The method can also include acquiring, with a sensor unit, light data that is reflected from the target. The light data may comprise a directly reflected spatial light pattern and a specular reflected spatial light pattern. The directly reflected spatial light pattern and the specular reflected spatial light pattern comprise at least one spatial distinction that distinguishes the directly reflected spatial light pattern from the specular reflected spatial light pattern. The method can further comprise processing the light data to distinguish the directly reflected spatial light pattern from the specular reflected spatial light pattern based upon the at least one spatial distinction.

Abstract: A method for facilitating removal of multipath signal interference from light data can comprise illuminating, with an illumination unit, a target with a light source. The illumination unit can be configured to project a high spatial-frequency pattern onto the target in such a way as to redistribute spectral energy to higher frequencies. The method can also comprise acquiring, with a sensor unit, reflected light data reflected from the target. The reflected light data can comprise an array of spatial domain information received from light reflected by the target. Further, the method can comprise processing, with the one or more processors, the reflected light data. The processing applies a high-pass filter within the spatial domain to the reflected light data.

Abstract: Data compression is described herein. The encoder transmits a coded word having replacement bits, as well as a code that defines the starting location of the replacement bits in a data sample. The replacement bits may be actual bits from a selected location in the new data sample. The selected location of the replacement bits can vary from data sample to data sample. The encoder may select the location based on the most significant bit that has changed. Thus, reconstructed data will be bit-accurate from the replaced bits all the way to the highest-order bit. A limited number of key values can be transmitted losslessly. Moreover, the data compression does not need forward error correction (FEC), which is a necessary part of many lossy delta encoding schemes. Furthermore, the encoding and decoding can be done very efficiently in terms of hardware and/or software.

Abstract: An apparatus for measuring intensity and/or range characteristics of an object(s), comprising: a signal source to emit modulation signals at a frequency(s); an illuminator to illuminate the object(s) by a first modulation signal; a sensor comprising a pixel(s), wherein the sensor creates a sampled correlated signal by sampling the correlation of a backscattered signal with a second modulation signal within the pixel; and a processor to determine range/intensity characteristics of component returns within the pixel(s) by comparing sampled correlated signals using measurements(s), wherein the measurement(s) comprise first and second modulation signals having a characteristic(s) selected from: (a) two or more different modulation frequencies, (b) a different modulation frequency(s) and an offset of the correlation waveform, and (c) another different modulation frequency(s) and one selected from: the zeroth spatial frequency of the signal returns versus range and an approximation of the zeroth spatial frequency o

Abstract: An apparatus for measuring intensity and/or range characteristics of an object(s), comprising: a signal source to emit modulation signals at a frequency(s); an illuminator to illuminate the object(s) by a first modulation signal; a sensor comprising a pixel(s), wherein the sensor creates a sampled correlated signal by sampling the correlation of a backscattered signal with a second modulation signal within the pixel; and a processor to determine range/intensity characteristics of component returns within the pixel(s) by comparing sampled correlated signals using measurements(s), wherein the measurement(s) comprise first and second modulation signals having a characteristic(s) selected from: (a) two or more different modulation frequencies, (b) a different modulation frequency(s) and an offset of the correlation waveform, and (c) another different modulation frequency(s) and one selected from: the zeroth spatial frequency of the signal returns versus range and an approximation of the zeroth spatial frequency o