Abstract: Apparatus and associated methods relate to a select frequency phase measurement (SFPM) time of flight (TOF) system including an emitter and a receiver. The emitter may generate a modulated emitted signal by at least one frequency. The emitted signal may, for example, be a pulsed light signal. The receiver may generate a signal in response to receiving a reflection of the emitted signal off a target object. An ADC element may digitize a signal generated by the receiving element, and a reference signal generated by a monitored signal of the modulated emitted signal. A processing element may generate a phase signal using single frequency analysis of the digitized signals. A distance measurement signal may be generated as a function of the phase signal. Various embodiments may, for example, advantageously enable sub-millisecond sensor response times using commodity processing elements.

Abstract: Apparatus and associated methods relate to pairing a receiver with an emitter based on a presence of an amplitude of a spectral profile at at least one predetermined frequency. In an illustrative example, a receiver may receive, from the emitter, an emitted optical signal modulated by the at least one predetermined frequency. A receiver may, for example, generate a digital signal corresponding to the optical signal received. A controller may, for example, generate the spectral profile from the digital signal. The controller may, for example, apply a predetermined threshold to the spectral profile. The controller may, for example, generate an output signal based on the presence of the amplitude of the spectral profile above the first predetermined threshold at the at least one predetermined frequency. Various embodiments may advantageously discriminate a corresponding emitter to establish an optical source-to-detector-link, for example, in the presence of other emitters and/or optically noisy environments.

Abstract: Apparatus and associated methods relate to pairing a receiver with an emitter based on a presence of an amplitude of a spectral profile at at least one predetermined frequency. In an illustrative example, a receiver may receive, from the emitter, an emitted optical signal modulated by the at least one predetermined frequency. A receiver may, for example, generate a digital signal corresponding to the optical signal received. A controller may, for example, generate the spectral profile from the digital signal. The controller may, for example, apply a predetermined threshold to the spectral profile. The controller may, for example, generate an output signal based on the presence of the amplitude of the spectral profile above the first predetermined threshold at the at least one predetermined frequency. Various embodiments may advantageously discriminate a corresponding emitter to establish an optical source-to-detector-link, for example, in the presence of other emitters and/or optically noisy environments.

Abstract: Apparatus and associated methods relate to a volumetric measurement system using three dimensional (3D) ToF cameras. In an illustrative example, a VMS may include at least one 3D distance sensor unit for monitoring a volume of objects in a region of interest (ROI). The VMS may, for example, include a set of user-defined parameters including the ROI, and temporal distribution of measurement attributes associated with the ROI. In some implementations, the VMS may be activated to automatically generate a set of error compensated volumetrics. For example, the VMS may apply a 3D profile, generated based on signals received from the 3D distance sensor, to an error compensation model. Based on measurement attributes generated from applying the error compensation model, the VMS may, for example, generate a set of error compensated volumetrics. Various embodiments may advantageously compensate for errors including occlusion of objects from the 3D distance sensor.

Abstract: Apparatus and associated methods relate to enabling a radar system to use different sensing mechanisms to estimate a distance from a target based on different detection zones (e.g., far-field and near-field). In an illustrative example, a curve fitting method may be applied for near-field sensing, and a Fourier transform may be used for far-field sensing. A predetermined set of rules may be applied to select when to use the near-field sensing mechanism and when to use the far-field mechanism. The frequency of a target signal within a beat signal that has less than two sinusoidal cycles may be estimated with improved accuracy. Accordingly, the distance of a target that is within a predetermined distance range (e.g., two meters range for 24 GHz ISM band limitation) may be reliably estimated.

Abstract: Apparatus and associated methods relate to enabling a radar system to use different sensing mechanisms to estimate a distance from a target based on different detection zones (e.g., far-field and near-field). In an illustrative example, a curve fitting method may be applied for near-field sensing, and a Fourier transform may be used for far-field sensing. A predetermined set of rules may be applied to select when to use the near-field sensing mechanism and when to use the far-field mechanism. The frequency of a target signal within a beat signal that has less than two sinusoidal cycles may be estimated with improved accuracy. Accordingly, the distance of a target that is within a predetermined distance range (e.g., two meters range for 24 GHz ISM band limitation) may be reliably estimated.

Abstract: Apparatus and associated methods relate to an open-loop control circuit (OLCC) configured to determine a photodiode element (PDE) drive voltage as a function of a commanded photodiode gain level and a measured temperature signal. In an illustrative example the OLCC may receive a current temperature of an APD element. The OLCC may, for example, receive a commanded gain for the APD relative to a predetermined reference gain. The OLCC may, for example, retrieve a predetermined efficiency characteristic (PEC) of the APD based on the current temperature. If the temperature corresponds to a substantially non-linear portion of the PEC, the OLCC may, for example, determine the drive voltage as a function of the temperature and the commanded gain based on the PEC. Various embodiments may advantageously provide direct control of output gain of photodiodes over a wide dynamic range of temperature associated with the photodiode.

Abstract: Apparatus and associated methods relate to pairing a receiver with an emitter based on a presence of an amplitude of a spectral profile at at least one predetermined frequency. In an illustrative example, a receiver may receive, from the emitter, an emitted optical signal modulated by the at least one predetermined frequency. A receiver may, for example, generate a digital signal corresponding to the optical signal received. A controller may, for example, generate the spectral profile from the digital signal. The controller may, for example, apply a predetermined threshold to the spectral profile. The controller may, for example, generate an output signal based on the presence of the amplitude of the spectral profile above the first predetermined threshold at the at least one predetermined frequency. Various embodiments may advantageously discriminate a corresponding emitter to establish an optical source-to-detector-link, for example, in the presence of other emitters and/or optically noisy environments.

Abstract: Apparatus and associated methods relate to an open-loop control circuit (OLCC) configured to determine a photodiode element (PDE) drive voltage as a function of a commanded photodiode gain level and a measured temperature signal. In an illustrative example the OLCC may receive a current temperature of an APD element. The OLCC may, for example, receive a commanded gain for the APD relative to a predetermined reference gain. The OLCC may, for example, retrieve a predetermined efficiency characteristic (PEC) of the APD based on the current temperature. If the temperature corresponds to a substantially non-linear portion of the PEC, the OLCC may, for example, determine the drive voltage as a function of the temperature and the commanded gain based on the PEC. Various embodiments may advantageously provide direct control of output gain of photodiodes over a wide dynamic range of temperature associated with the photodiode.

Abstract: Apparatus and associated methods relate to an open-loop control circuit (OLCC) configured to determine a lasing element drive current as a function of a commanded optical power signal and a measured temperature signal, where the absolute value of the second derivative of the optical output power with respect to laser drive current exceeds a predetermined threshold. In an illustrative example, the absolute value of the second derivative may exceed the predetermined threshold in a non-linear operating region of the laser element. The non-linear operating region may represent, for example, a characteristic output power vs. drive current curve of the lasing element. The OLCC may provide laser peak power control for arbitrary peak power, within linear and non-linear regions of laser efficiency. In some embodiments, the OLCC may substantially improve control over laser optical output power over a wide dynamic range of, for example, temperature associated with the lasing element.

Abstract: Multiple signal characteristics representing an entire field of view of an FMCW (FM-CW) sensor are evaluated to determine whether the field of view has changed. Signal characteristics representing the field can be compared to representative signal characteristics obtained from previous scans. At least one signal characteristic representing at least a portion of the scene can be evaluated by comparing the signal characteristic to a dynamic threshold. The dynamic threshold can be redefined after each scan from the statistics of the signal characteristic. The dead zone of a sensor can be reduced by filtering out noise that would otherwise overshadow a signal representing the near-field region of a scene. The noise can be filtered by subtracting a polynomial curve from a time-domain signal representing the scene after fitting the polynomial curve to a representative signal generated based on previous scene scans.

Abstract: Multiple signal characteristics representing an entire field of view of an FMCW (FM-CW) sensor are evaluated to determine whether the field of view has changed. Signal characteristics representing the field can be compared to representative signal characteristics obtained from previous scans. At least one signal characteristic representing at least a portion of the scene can be evaluated by comparing the signal characteristic to a dynamic threshold. The dynamic threshold can be redefined after each scan from the statistics of the signal characteristic. The dead zone of a sensor can be reduced by filtering out noise that would otherwise overshadow a signal representing the near-field region of a scene. The noise can be filtered by subtracting a polynomial curve from a time-domain signal representing the scene after fitting the polynomial curve to a representative signal generated based on previous scene scans.