An optical receiver including an ASIC, a light detector element, and a protective mask is disclosed. The light detector element is disposed on the ASIC and has a top surface oriented toward incident light, the top surface including a portion configured to receive the incident light and via which the incident light reaches an active area of the light detector element. The protective mask is placed over the ASIC so as to (i) cover, from the incident light, a portion of the ASIC, and (ii) provide an aperture that defines an optical path for the incident light through the protective mask to the portion of the top surface of the light detector element.

A method for optical distance measurement is provided, which comprises emitting a plurality of measurement pulses, reflecting emitted measurement pulses on at least one object within a measurement range with a length and receiving reflected measurement pulses. N subsets of measurement pulses are emitted, wherein each subset comprises a constant pulse interval. The constant pulse interval of different subsets is different, wherein the least common multiple of the constant pulse intervals of the N subsets corresponds to at least twice the length of the measurement range.

A light signal detection device includes a light receiving optical system configured to receive a reflection signal reflected from an object when irradiation light emitted from an irradiation unit hits the object and reflects from the object; and circuitry configured to binarize the received reflection signal using a first threshold value, based on a determination of whether the reflection signal is equal to or greater than the first threshold value; binarize the received reflection signal using a second threshold value set with a given value similar to a noise signal value, based on a determination of whether the reflection signal is equal to or greater than the second threshold value; and measure a time difference between a time of emitting the irradiation light from the irradiation unit and a time of receiving a reflection signal equal to or greater than the first threshold value or the second threshold value.

A light signal detection device includes a light receiving optical system configured to receive a reflection signal reflected from an object when irradiation light emitted from an irradiation unit hits the object and reflects from the object; and circuitry configured to binarize the received reflection signal using a first threshold value, based on a determination of whether the reflection signal is equal to or greater than the first threshold value; binarize the received reflection signal using a second threshold value set with a given value similar to a noise signal value, based on a determination of whether the reflection signal is equal to or greater than the second threshold value; and measure a time difference between a time of emitting the irradiation light from the irradiation unit and a time of receiving a reflection signal equal to or greater than the first threshold value or the second threshold value.

A digital counting and display system and methods for use with a laser rangefinder that counts backscattered laser beams and displays a distance between a laser and a target. The laser rangefinder includes a laser configured to emit a pulsed laser beam, an afocal Gallilean telescope configured to receive backscattered laser pulses and generate a series of focused backscattered laser pulses, a silicon avalanche photodetector connected to the afocal Gallilean telescope, configured to generate a series of currents signal proportional to the series of focused backscattered laser pulses, a low noise, multistage amplifier connected to the silicon avalanche photodetector, configured to generate a series of linearly changing amplified voltage signals from the series of current signals, an analog-to-digital converter configured to convert the series of linearly changing amplified voltage signals to a series of digital voltage signals, and a digital counting and display circuit connected to the analog-digital converter.

A digital counting and display system and methods for use with a laser rangefinder that counts backscattered laser beams and displays a distance between a laser and a target. The laser rangefinder includes a laser configured to emit a pulsed laser beam, an afocal Gallilean telescope configured to receive backscattered laser pulses and generate a series of focused backscattered laser pulses, a silicon avalanche photodetector connected to the afocal Gallilean telescope, configured to generate a series of currents signal proportional to the series of focused backscattered laser pulses, a low noise, multistage amplifier connected to the silicon avalanche photodetector, configured to generate a series of linearly changing amplified voltage signals from the series of current signals, an analog-to-digital converter configured to convert the series of linearly changing amplified voltage signals to a series of digital voltage signals, and a digital counting and display circuit connected to the analog-digital converter.

A receiver of a lidar system configured to receive one or more scattered light pulses from a target in a field of regard of the lidar system. The receiver includes a detector that emits an electric signal representative of the received light pulse in response to detecting the received light pulse. The receiver further includes one or more analog circuits configured to receive the electric signal from the detector, sample one or more voltages of the electric signal, and determine the energy of the received light pulse based at least on the one or more sampled voltages. The lidar system may further calculate a reflectivity and/or other characteristics of the target based at least on the energy of the received light pulse.

Provided are a LIDAR signal processing apparatus and a LIDAR signal processing method. The LIDAR signal processing apparatus comprises: an inherent history pulse wave applying unit for applying a first pulse wave combination to a laser diode, the first pulse wave combination having an inherent history which includes a combination of an inherent pulse period and an inherent pulse variation value; a received history detecting unit for detecting a received signal period and a received signal variation value of a reflected wave received by a photodiode; an inherent pulse wave discriminating unit for deciding whether or not the received signal period and the received signal variation value coincide with the inherent history; and an effective data processing unit for measuring a distance using effective data when the received signal period and the received signal variation value coincide with the inherent history.

Provided are a LIDAR signal processing apparatus and a LIDAR signal processing method. The LIDAR signal processing apparatus comprises: an inherent history pulse wave applying unit for applying a first pulse wave combination to a laser diode, the first pulse wave combination having an inherent history which includes a combination of an inherent pulse period and an inherent pulse variation value; a received history detecting unit for detecting a received signal period and a received signal variation value of a reflected wave received by a photodiode; an inherent pulse wave discriminating unit for deciding whether or not the received signal period and the received signal variation value coincide with the inherent history; and an effective data processing unit for measuring a distance using effective data when the received signal period and the received signal variation value coincide with the inherent history.

A multiple-pulses-in-air (MPiA) laser scanning system, wherein the MPiA problem is addressed in that an MPiA assignment of return pulses to send pulses of a laser scanner is based on range tracking and range probing at intermittent points in time. Each range probing comprises a time-of-flight arrangement which is constructed to be free of the MPiA problem. The invention further relates to an MPiA laser scanning system, wherein an MPiA ambiguity within a time series of return pulses, is converted into 3D point cloud space, which provides additional information from the spatial neighborhood of the points in question to enable MPiA disambiguation.