The present invention relates to a tracker and a surveying apparatus comprising the tracker, which improve the reliability of tracking a target. The tracker comprises a first imaging region having a plurality of pixels for taking a first image of a scene including the target; a second imaging region having a plurality of pixels for taking a second image of a scene including the target; a control unit to receive a timing signal indicating a time duration during which an illumination illuminating the target in the scene is switched on and off, control the first imaging region to take the first image of the scene when the timing signal indicates that the illumination unit is switched on, and control the second imaging region to take the second image when the illumination is switched off; and a read out unit configured to read out the first image from the first imaging region and the second image from the second imaging region and to obtain a difference image.

A method of measuring a distance using a time of flight sensor comprising a substantially transparent cover covering a light emitter and one or more photodetectors. The method comprises emitting a series of pulses of light from the light emitter; and using the one or more photodetectors to obtain a distribution of times at which at least one photodetector of the one or more photodetectors detected photons after each emission of the series of pulses of light. If the distribution of times comprises only a single peak, the method further comprises analysing the single peak to determine if the single peak includes counts of photons reflected from a target. If the single peak includes counts of photons reflected from a target, the method further comprises measuring the separation between a reference time and a point of the single peak.

An optical testing apparatus is used in testing an optical measuring instrument that provides incident light from a light source to an incident object and receives reflected light of the incident light at the incident object. The apparatus includes an incident light receiving section, a light signal providing section, an imaging section, and an optical axis misalignment deriving section. The incident light receiving section receives incident light. The light signal providing section provides a light signal to an incident object after a predetermined delay time since the incident light receiving section has received the incident light. The imaging section images the incident light. The optical axis misalignment deriving section derives misalignment of the optical axis of the incident light with respect to the incident light receiving section based on misalignment between the incident light receiving section and the imaging section as well as an imaging result with the imaging section.

Provided are a light receiving device, a light receiving circuit, and a distance measuring device capable of minimizing dead time.

A light receiving device according to the present disclosure may include: a light receiving circuit including a light receiving element; a power supply circuit configured to supply a power supply potential to the light receiving circuit; and a control circuit configured to control the power supply potential supplied by the power supply circuit on the basis of a signal output from the light receiving circuit in a reaction with a photon.

Provided are a light receiving device, a light receiving circuit, and a distance measuring device capable of minimizing dead time.

A light receiving device according to the present disclosure may include: a light receiving circuit including a light receiving element; a power supply circuit configured to supply a power supply potential to the light receiving circuit; and a control circuit configured to control the power supply potential supplied by the power supply circuit on the basis of a signal output from the light receiving circuit in a reaction with a photon.

The present technology relates to an observation apparatus, an observation method, and a distance measurement system capable of improving distance measurement accuracy. A first measurement unit that measures a first number of reactions of a light receiving element in response to incidence of photons on a first pixel, a second measurement unit that measures a second number of reactions of the light receiving element in response to incidence of photons on a second pixel, a light emitting unit that emits light to the second pixel, and a light emission control unit that controls the light emitting unit according to a difference between the first number of reactions and the second number of reactions are included. The present technology can be applied to, for example, a distance measurement apparatus that measures a distance to a predetermined object, and can be applied to an observation apparatus that observes a characteristic of a pixel included in the distance measurement apparatus.

Provided is a phase difference calculation device including a first light amount acquisition unit that acquires a first light amount of reflected light of light applied in a first time window and received in the first time window and a second light amount of the reflected light received in a second time window, a time window shift control unit that shifts the first and second time windows and a third time window in the negative direction of the time axis to set fourth, fifth, and sixth time windows, and shifts the fourth, fifth, and sixth time windows in the negative direction of the time axis until no reflected light is received in the fourth time window, a second light amount acquisition unit that acquires a third light amount of the reflected light received in the sixth time window, and a phase difference calculation unit that calculates a phase difference between the light and the reflected light on the basis of a first corrected light amount obtained by adding the third light amount to the first light amount and a second corrected light amount obtained by subtracting the third light amount from the second light amount.

Provided is a phase difference calculation device including a first light amount acquisition unit that acquires a first light amount of reflected light of light applied in a first time window and received in the first time window and a second light amount of the reflected light received in a second time window, a time window shift control unit that shifts the first and second time windows and a third time window in the negative direction of the time axis to set fourth, fifth, and sixth time windows, and shifts the fourth, fifth, and sixth time windows in the negative direction of the time axis until no reflected light is received in the fourth time window, a second light amount acquisition unit that acquires a third light amount of the reflected light received in the sixth time window, and a phase difference calculation unit that calculates a phase difference between the light and the reflected light on the basis of a first corrected light amount obtained by adding the third light amount to the first light amount and a second corrected light amount obtained by subtracting the third light amount from the second light amount.

A distance measurement apparatus of a scanning type provided with a two-dimensional micro electro mechanical system (MEMS) mirror that reflects a laser beam includes: a first detector that detects a mirror angle of the two-dimensional MEMS mirror and outputs an angular signal that indicates the mirror angle; and a processor that calculates an amplitude error and a phase error between amplitude and a phase of the angular signal and amplitude and a phase of a reference angle signal, and corrects a resonance drive waveform of a drive signal that drives, of two mutually orthogonal axes of the two-dimensional MEMS mirror, one axis on a resonance drive side on a basis of the amplitude error and the phase error.

A frequency modulation continuous wave (FMCW)-based system configured to convert measurements of a linearly modulated wave from a time-domain into a frequency-domain to produce a non-linear frequency signal, where the non-linear frequency signal comprises a known linear component representing the desired linear modulation and an unknown non-linear component representing the non-linearity of the modulation. The FMCW-based system is further configured to determine coefficients of a basis function approximating a difference between the non-linear frequency signal and the linear frequency component in the frequency domain. The FMCW-based system is further configured to detect one or multiple spectrum peaks in the distorted beat signal with the distortion compensated according to the basis function with the determined coefficients to determine one or multiple distances to the one or multiple objects in the scene.