Denso Corporation

Takehiro Hata

Noriyuki Ozaki

Teiyu Kimura

Shinji Kashiwada

Kenta Azuma

Hiroyuki Matsubara

Isamu Takai

Akifumi Ueno

Mineki Soga

An optical distance measuring apparatus comprises a laser diode emitting a light pulse, light receiver including a photon-counting light receiver, distance measurement unit including a signal discriminator and propagation estimator, and threshold determiner. The signal discriminator discriminates the signal component, exceeding a threshold, of the signal as a reflected signal resulting from reflection of the light pulse at a measurement object. The propagation estimator estimates a round-trip propagation time of the light pulse to the measurement object using the signal. The threshold determiner sets a boundary level as the threshold, corresponding to a reference level obtained from the signal when the signal discriminator determines the reflected signal, using the relationship between the reference and the boundary level. The reference level is obtained from the average value of a noise probability distribution in the signal. The boundary level represents a predetermined cumulative probability in the noise probability distribution.

Optical distance measuring apparatus

A distance measuring apparatus is provided which includes an illuminator, a plurality of photodetectors which detect reflected light arising from reflection of light, as emitted from the illuminator, from an object using SPADs, a time measuring unit which measures time elapsed after the emission of light from the illuminator until a number of the photodetectors which is larger than a given value have detected light, a timing controller which instructs the illuminator to emit the light, activates the SPADs in a Geiger mode, and instructs the time measuring unit to execute the time measurement, and a timing instruction unit which determines a light emission timing and an activation start timing of each of the SPADs for the timing controller.

Distance measuring apparatus

A light reception array unit receives light irradiated from an irradiation unit and reflected from an object, and outputs in parallel a pulse signal respectively output from a plurality of light reception units. A timer unit measures an elapsed time since an input of an irradiation timing signal. A response acquisition unit acquires a number of responses, which is a number of the light reception units outputting the pulse signal, at each fixed cycle timing, and outputs an adjusted number of responses obtained by subtracting a bias value from the number of responses or dividing the number of responses by the bias value. An address of a memory is associated with a timer value measured by the timer unit. A histogram generation unit integrates and stores, in a memory address specified from a timer value, the adjusted number of responses as data at that address.

Photodetector

An optical distance measurement apparatus that measures a distance using a round-trip time of light to an object includes an irradiator, a plurality of SPADs, a plurality of signal output units, a response number detector, a timing identifier, and a timing corrector. The response number detector detects a response number representing the number of responding one of the SPADs based on a pulse signal. The timing identifier identifies a temporary timing based on a state of variation in the response number along a time series and identifies a detection timing representing a timing when the optical distance measurement apparatus detects light in accordance with the temporary timing. The timing corrector acquires a correction time representing a time difference between the temporary timing and a true timing corresponding to a distance to an object and sets a timing corrected from the temporary timing by the correction time as the detection timing.

Distance measurement apparatus with detection timing correction

A plurality of photodetectors form a light receiving group, and a plurality of the light receiving groups form one pixel. A light receiving array is provided with one or more of such pixels. The photodetectors each output a pulse signal in response to irradiation of a photon. A measuring unit is provided for each of the plurality of light receiving groups. The measuring unit generates time information representing an elapsed time from an irradiation timing input from outside and light quantity information acquired at each of one or more timings identified from the time information, in accordance with the pulse signal output from the light receiving group. The number of the photodetectors outputting the pulse signal among the plurality of photodetectors belonging to the light receiving group is used as the light quantity information.

Optical measuring device comprising a measuring unit to generate time information representing an elapsed time in accordance with pulse signal output from a light receiving group

A light detector is provided to include a detection module, and a monitoring SPAD. The detection module includes an SPAD that is an avalanche photodiode operable in Geiger mode; the detection module is configured to perform light detection by applying, to the SPAD, a reverse bias voltage in a reverse direction. The monitoring SPAD has characteristics identical to characteristics of the SPAD in the detection module. The reverse bias voltage is generated to be applied to the SPAD in the detection module based on (i) a reference breakdown voltage set from a breakdown voltage generated across the monitoring SPAD in Geiger mode and (ii) a predetermined excess voltage.

Light detector having monitoring single photon avalanche diode (SPAD)

A light detection device has light receiving parts, edge detection circuits and an addition unit. Each light receiving part has a quench resistance, a SPAD and a pulse signal output part. The SPAD responses incident photons, i.e. incident light. The quench resistance and pulse signal output part generate and transmit a pulse signal to a corresponding edge detection circuit when the SPAD receives and responds to the incident light. The edge detection circuits and the addition unit detects the number of edges during a period from a previously received CLK signal to a currently received CLK signal every time it receives a CLK signal transmitted at a predetermined period. The edge represents a state change from a first state which receives no pulse signal to a second state which receives the pulse signal.

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Kariya, Japan

Takehiro Hata