Provided is a distance measuring device which allows the measurement accuracy to be improved while the memory size is reduced. A distance measuring device includes a light emitting element which emits range-finding light as pulse light, a light receiving element which receives reflected range-finding light obtained as the range-finding light is reflected on a measurement object, an AD converter which converts the light reception signal output from the light receiving element from an analogue signal to a digital signal, multiple memories which have different memory sizes from each other and store sampled data output from the AD converter, and a rough distance calculator which calculates a distance on the basis of the sampled data stored in the multiple memories.

Provided is a distance measuring device which allows the measurement accuracy to be improved while the memory size is reduced. A distance measuring device includes a light emitting element which emits range-finding light as pulse light, a light receiving element which receives reflected range-finding light obtained as the range-finding light is reflected on a measurement object, an AD converter which converts the light reception signal output from the light receiving element from an analogue signal to a digital signal, multiple memories which have different memory sizes from each other and store sampled data output from the AD converter, and a rough distance calculator which calculates a distance on the basis of the sampled data stored in the multiple memories.

A signal extraction circuit, a signal extraction method, and a distance measurement method and device. The distance measurement method comprises: performing multiple signal extractions using a circuit in a sensor, so as to obtain multiple extraction results; and determining the distance to a measurement object according to the multiple extraction results. Compared with pixel circuits in the prior art, the signal extraction circuit reduces the number of capacitors by half, thereby significantly increasing effective areas in pixels, and reducing calculation errors resulting from capacitance differences between the various capacitors. Moreover, part of the calculation is completed during the signal extraction, thus reducing the pressure of subsequent data processing, and particularly improving the accuracy and speed of distance measurement during the distance measurement process.

In one example, an apparatus includes a TLT (Time of Flight (TOF)/LiDAR tool) with one or more optical transmitters and optical receivers that are operable to cooperate to obtain data concerning a downhole feature when the apparatus is deployed in a downhole environment. This apparatus further includes a first device operable to determine a position, speed, and/or orientation, of the TLT, when the TLT is deployed in the downhole environment, a second device configured to store locally and/or transmit the data to a location on a surface, a power source connected to the TLT, the first device, and the second device, and a housing within which the TLT, first device, second device, and power source are disposed, and the housing includes a connector configured to interface with a piece of downhole equipment.

In one example, an apparatus includes a TLT (Time of Flight (TOF)/LiDAR tool) with one or more optical transmitters and optical receivers that are operable to cooperate to obtain data concerning a downhole feature when the apparatus is deployed in a downhole environment. This apparatus further includes a first device operable to determine a position, speed, and/or orientation, of the TLT, when the TLT is deployed in the downhole environment, a second device configured to store locally and/or transmit the data to a location on a surface, a power source connected to the TLT, the first device, and the second device, and a housing within which the TLT, first device, second device, and power source are disposed, and the housing includes a connector configured to interface with a piece of downhole equipment.

A position reference sensor (100) has a light source (120), a detector (160) and a processor (170). The light source (120) is configured to emit light having a first component and a second component. The detector (160) is configured to detect reflected light. The processor (170) is configured to determine a distance between the position reference sensor (100) and a target based on the emitted light and the detected reflected light. The processor (170) is also configured to determine that the target is a selective retroreflector (140) based on the intensity of the first component of the light in the detected reflected light and the intensity of the second component of the light in the detected reflected light.

A LIDAR system includes a transmitting device for light; a receiving device for light, including a first and a second photon detector; and an evaluation device that is configured for determining a time period between the emission of light with the aid of the transmitting device and the incidence at the receiving device of the light reflected on an object. The transmitting device is configured for emitting a superimposition of horizontally and vertically polarized light; the first photon detector is configured for detecting only horizontally polarized light, and the second photon detector is configured for detecting only vertically polarized light; in addition, the evaluation device is configured for determining the time period, based on light that is incident on both photon detectors within a predetermined interval.

The disclosed technology can be implemented in photonics integrated circuit (PIC) to provide an optical frequency detection device for measuring an optical frequency of light using two Mach-Zehnder interferometer where the delay imbalance in the first interferometer is configured to be one quarter wavelength longer than that of the second interferometer to produce an additional phase difference between the two arms. The two outputs of each interferometer are then detected by two photodetectors to produce two complementary interference signals. The difference between the two complementary interference signals of the first interferometer is a sine function of the optical frequency while the difference between the two complementary interference signals of the second interferometer is proportional to a cosine function of the optical frequency. Using the sine/cosine interpretation algorithm commonly used for the rotation encoders/decoders, any increments in optical frequency can be readily obtained.

The disclosed technology can be implemented in photonics integrated circuit (PIC) to provide an optical frequency detection device for measuring an optical frequency of light using two Mach-Zehnder interferometer where the delay imbalance in the first interferometer is configured to be one quarter wavelength longer than that of the second interferometer to produce an additional phase difference between the two arms. The two outputs of each interferometer are then detected by two photodetectors to produce two complementary interference signals. The difference between the two complementary interference signals of the first interferometer is a sine function of the optical frequency while the difference between the two complementary interference signals of the second interferometer is proportional to a cosine function of the optical frequency. Using the sine/cosine interpretation algorithm commonly used for the rotation encoders/decoders, any increments in optical frequency can be readily obtained.

An optical sensing apparatus is provided. A bias-voltage generating circuit provides a first bias voltage and a second bias voltage to a photo-sensing diode when the optical sensing apparatus is respectively in a first mode and a second mode, such that the photo-sensing diode provides a time-of-flight ranging signal in the first mode and an ambient-light sensing signal in the second mode. A quenching circuit provides the time-of-flight ranging signal to a ranging signal processing circuit in the first mode, quenches the photo-sensing diode, and provides the ambient-light sensing signal to a light-sensing signal processing circuit in the second mode.