An apparatus for three-dimensional shape measurement is provided, including a projection device, an image capture device, and an image processing device. The projection device sequentially projects a plurality of structured light beams on a scene during a first projection period and a second projection period. The mean level of the structured light beams during the first projection period is the same as the mean level of the structured light beams during the second projection period, and the frequency of the structured light beams during the first projection period is different from the frequency of the structured light beams during the second projection period. The image capture device captures an image of the scene within the projection time of each of the structured light beams. The image processing device obtains a three-dimensional shape of a to-be-measured object in the scene according to the images.

A system can include an axis, a motor coupled with the axis and configured to rotate the axis, an optical modulator coupled with the axis and configured to be rotated by the axis, a lens element, a projection surface, a laser device configured to shine light through the optical modulator to project structured light onto the projection surface through the lens element, and a sensor configured to capture an image of a sample and structured light that is reflected from the projection surface and the sample surface. The system can also include a computing system having a synchronization module configured to phase lock the system by coordinating the laser device and the sensor and an analysis module configured to compute a three-dimensional (3D) object based on the structured light that is reflected from the projection surface and the sample surface.

Projection device switches and projects a plurality of types of pattern images in a unit of projection frame. Imaging device images object to which the pattern image is projected and generates image data. Measurement device discriminates whether each imaging frame is a key frame of the image data obtained by capturing one of the pattern images or a blended frame of the image data obtained by capturing a plurality of the pattern images switched during an exposure period of one frame, and performs measurement based on a space coding method by using at least the image data of the key frame.

This disclosure relates to optical three-dimensional (3D) measurement, and more particularly to a large-depth-range 3D measurement method, system, and device based on phase fusion. Sinusoidal fringes corresponding to multiple high-frequency binary fringe patterns varying in stripe width, a middle-frequency binary fringe pattern, and a low-frequency binary fringe pattern are formed and then projected onto a to-be-measured object. After modulated by height of the object, the sinusoidal fringes are collected, and wrapped phases of the collected sinusoidal fringes are calculated to determine absolute phases of high-frequency sinusoidal fringes. Phase errors of a high-frequency sinusoidal fringe under different fringe widths are calculated according to the defocusing degree. An optimal absolute phase is selected based on the phase errors for the large-depth range 3D measurement.

Provided is a generation method for a programmable analog fringe pattern with an extended depth of field. A laser emits a laser beam. After focusing and collimation thereof with a collimating lens, a collimated Gaussian laser beam meeting requirements is obtained. The laser beam is reflected by a mirror once, passes through a round diaphragm and is incident on a MEMS scanning mirror. The beam is reflected by the MEMS scanning mirror to the surface of a tested object. The laser is controlled by a sinusoidal current signal generated by a drive board so as to sinusoidally modulate the brightness of the laser beam. The MEMS scanning mirror is stimulated by a drive signal generated by the drive board to turn two-dimensionally, so as to drive the laser beam to perform scanning, thus generating a fringe pattern image.

A system for structured light depth computation using single photon avalanche diodes (SPADs) is configurable to, over a frame capture time period, selectively activate the illuminator to perform interleaved structured light illumination operations. The interleaved structured light illumination operations comprise alternately emitting at least a first structured light pattern from the illuminator and emitting at least a second structured light pattern from the illuminator. The system is also configurable to, over the frame capture time period, perform a plurality of sequential shutter operations to configure each SPAD pixel of the SPAD array to enable photon detection. The plurality of sequential shutter operations generates, for each SPAD pixel of the SPAD array, a plurality of binary counts indicating whether a photon was detected during each of the plurality of sequential shutter operations.

Provided herein are systems, methods, and apparatuses for Structured Light Part Quality Monitoring for Additive Manufacturing.

A distance measuring device includes a light output unit outputting a linear laser beam, a light scanning unit including a mirror that reflects the laser beam from the light output unit while swinging and generating a pattern light on an object, a light detection unit placed in a position equal to or less than 90% of maximum swing amplitude of the mirror, and receiving the light reflected by the mirror and outputting a light reception signal, an imaging unit imaging the pattern light, a measuring unit measuring a distance to the object based on a result of imaging by the imaging unit, and a control unit controlling generation of the pattern light based on the light reception signal.

A three-dimensional scanning system includes a projection light source, an image capturing apparatus, and a signal processing apparatus. The projection light source is configured to project a two-dimensional light to a target, where the two-dimensional light has a spatial frequency. The image capturing apparatus captures an image of the target illuminated with the two-dimensional light. The signal processing apparatus is coupled to the projection light source and the image capturing apparatus, to analyze a definition of the image of the two-dimensional light, where if the definition of the image of the two-dimensional light is lower than a requirement standard, the spatial frequency of the two-dimensional light is reduced.

An imaging processing part 131 executes first imaging processing of causing a first illuminating part to emit structured light from a first direction to a measurement target, causing an imaging part 120 to generate image data, and causing a buffer memory 133 to store therein the generated image data. A computing processing part 132 executes first computing processing of generating, height data corresponding to the first direction. Concurrently with the first computing processing, the imaging processing part 131 executes second imaging processing of causing the second illuminating part to emit structured light from a second direction to the measurement target, causing the imaging part 120 to generate image data, and causing a buffer memory 134 to store therein the generated image data. The computing processing part 132 executes second computing processing of generating height data corresponding to the second direction.