An encoder including a rotary disc that rotates around a rotating shaft, and a sensor that detects a rotational position of the rotary disc, in which the rotary disc is provided with first patterns and second patterns, the first patterns are arranged at positions obtained by equally dividing a first circumference which is a circumference of a first circle into M (M is natural number of 2 or more) at intervals, the second patterns are arranged at positions obtained by equally dividing a second circumference which is a circumference of a second circle which is a concentric circle of the first circle and has a different radius from that of the first circle into N (N is natural number of 2 or more) at intervals, and M and N are different from each other and a greatest common divisor of M and N is 1.

An encoder apparatus includes an encoder and a processor. The encoder includes a scale portion, a light emitting portion, and a light receiving portion. The scale portion includes a first track and a second track. The processor obtains a plurality of candidate values of a gap between the light emitting portion and the scale portion on a basis of an amplitude of a first signal obtained by receiving light reflected on or transmitted through the first track by the light receiving portion. The processor determines a measured value from among the plurality of candidate values on a basis of an amplitude of a second signal obtained by receiving light reflected on or transmitted through the second track by the light receiving portion.

A scale has marks whose pitch interval changes along a measurement direction in a manner that can be approximated to a quadratic or higher-order polynomial. A comparing unit calculates a difference between first relative position information and second relative position information per unit displacement in a position where a first displacement detecting unit is arranged. Then, an absolute position computing unit computes an absolute position in the measurement direction with respect to the scale based on absolute position information and the relative position information of at least one of the first relative position information and the second relative position information, and outputs the absolute position.

Provided is an optical encoder, including: a light receiving unit; and a scale moving relatively to the light receiving unit and including a first track and a second track each having patterns intended for projecting light onto the light receiving unit, wherein the number of patterns of the first track is Ns*Nd+i (where, Ns and i are an integer of 1 or greater, and Nd is an integer of 2 or greater), and the number of patterns of the second track is (Ns1)*Nd+i, so an absolute angle of the scale can be calculated in real time and in high resolution.

An encoder includes: an emitter that emits light; a rotary plate that rotates and includes an annular region that reflects the light emitted from the emitter, the annular region being provided surrounding a rotation axis of the rotary plate; and a light receiver that receives light emitted from the emitter and arriving via the annular region. The light receiver includes: a first set that includes a first light-receiving region and a second light-receiving region that are arranged side by side in a first direction intersecting a rotation direction of rotary plate; and a second set that includes a third light-receiving region and a fourth light-receiving region that are arranged side by side in a second direction intersecting the rotation direction and that is provided side by side with the first set in the rotation direction.

Disclosed are systems, methods, and structures that mitigate accumulative error in relative-measurement DFOS by employing, for each segment of the DFOS arrangement that records a certain number of an earlier estimation of each spatial segment. A predictive model in each buffer learns trends from the recorded history and predicts an output from the previous history. The reference is also updated using the prediction from the buffer. Systems, methods, and structures according to the present disclosure include the buffer structure that records a certain number of earlier estimations for each segment, a predictive model in each buffer that predicts the output of each segment according to the earlier estimations, reference updates using the prediction from the buffer tracker and workflow of real-time data processing with the buffer structure and tracker.

A digital adaptive optics encoder module includes an input mounting flange, a collimating lens, a bandpass filter, digital adaptive optic elements, refocusing lens, an output mounting flange, and a housing. The input mounting flange is capable of attaching to a telescope. The collimating lens is capable of expanding light from a target to fill a plurality of primary apertures. The bandpass filter has a bandwidth ranging from about 40 nm to about 100 nm. The digital adaptive optic elements include the plurality of primary apertures, an optical spreader, a focusing optic, and a detector. The refocusing lens is capable of refocusing an output from the digital adaptive optic elements onto a sensor plane. The output mounting flange is capable of attaching to an output connection. The housing encloses all of the interior components of the digital adaptive optics encoder module.

An optical sensing assembly includes a scale, a sensor, and a light source. The scale includes first and second pattern areas. The first pattern area includes first patterns periodically arranged in first and second directions. The second pattern area includes second patterns periodically arranged in the first and second directions. The sensor is configured to move relative to the scale in the first direction and includes first, second, third, and fourth sensing areas. The first and third sensing areas are configured to sense changes of the first pattern area in the first and second directions respectively. The second and fourth sensing areas are configured to sense changes of the second pattern area in the first and second directions respectively. The light source is configured to emit light toward the scale.

An optical sensing assembly includes a scale, a sensor, and a light source. The scale includes a first pattern area and a second pattern area. The first pattern area includes first patterns periodically arranged in the first direction. The second pattern area includes second patterns periodically arranged in the first direction and a second direction. The sensor is configured to move relative to the scale in the first direction and includes a first sensing area, a second sensing area, and a third sensing area. The first sensing area is configured to sense a change of the first pattern area in the first direction. The second sensing area and the third sensing area are configured to sense changes of the second pattern area respectively in the first direction and the second direction. The light source is configured to emit light toward the scale.