Patent•
Phase shifting optical projection three-dimensional measuring system and method
23 Nov 2016-
TL;DR: In this article, a phase shifting optical projection three-dimensional measuring system and method was proposed, which combines an acousto-optic modulation technology with phase shifting fringe frequency conversion technology, fast measures the three dimensional morphologies of the surfaces of the multiple objects with different structures on-machine, has the strong vibration resistance capability, realizes the onmachine measurement in a processing process, and especially has strong robustness for the object surface with complex structure.
Abstract: The invention relates to a phase shifting optical projection three-dimensional measuring system and method. A laser is generated by a single-mode laser device and is expanded into light beams through an optical beam expanding system. The light beams pass through a one-dimensional beam splitting grating and forms two light beams. The two light beams pass through an acousto-optic modulator and generate Bragg diffraction and are projected to a beam-combiner after angles are adjusted to form an interference light path. The interference light path passes through a focusing lens and is amplified by a projection object lens. Interference fringes are generated and projected to a measured object. The interference fringes projected on a surface of the measured object are captured by a CCD camera. The interference fringes are processed by a computer and finally a three-dimensional morphology of the measured object is recovered. The system combines an acousto-optic modulation technology with a phase shifting fringe frequency conversion technology, fast measures the three dimensional morphologies of the surfaces of the multiple objects with different structures on-machine, has the strong vibration resistance capability, realizes the on-machine measurement in a processing process, and especially has strong robustness for the object surface with the complex structure.
Citations
More filters
Patent•
19 Mar 2019
TL;DR: In this paper, a three-dimensional measurement method based on improved multi-frequency stripe structured light is described, which can be applied on the surfaces of large objects complex in profile and drastic in transition, and is characterized by comprising of the following steps of 1, generating multiscale coded stripe images; 2, conducting camera calibration; 3, conducting projector calibration; 4, projecting the coded stripe image and calculating an absolute phase of a stripe image the frequency of which is fn; 5, conducting 3D reconstruction measurement.
Abstract: The invention discloses a three-dimensional measurement method based on improved multi-frequency stripe structured light. The method is characterized by comprising the following steps of 1, generatingmulti-frequency coded stripe images; 2, conducting camera calibration; 3, conducting projector calibration; 4, projecting the coded stripe images and calculating an absolute phase of a stripe image the frequency of which is fn; 5, conducting three-dimensional reconstruction measurement. According to the method, applied equipment is simple, the cost is low, and precise three-dimensional measurement can be carried out on the surfaces of large objects complex in profile and drastic in transition.
6 citations
Patent•
22 Dec 2017
TL;DR: In this article, a structured light lighting device consisting of a laser, a half-wave plate, a condenser lens, a beam splitter, a reflector, an optical length delay module, and a Dove prism and a halfwave plate which are rotationally arranged in an optical path is presented.
Abstract: The invention provides a structured light lighting device and a method of producing striped structured light. The structured light lighting device includes a laser, a half-wave plate, a condenser lens, a beam splitter, a reflector, an optical length delay module, and a Dove prism and a half-wave plate which are rotationally arranged in an optical path. Linearly polarized light emitted by the laser passes through the half-wave plate and the condenser lens in sequence, and is then split by the beam splitter into a reflected beam and a transmitted beam. The reflected beam enters the optical length delay module. The transmitted beam is reflected by the reflector to the optical length delay module. After the reflected beam and the transmitted beam pass through the optical length delay module, two lighting beams with the same optical length are formed. After the two lighting beams pass through the Dove prism and the half-wave plate, two spots are generated in a plane P1. A method of producing striped structured light is further provided. With the structured light lighting device adopted, problems such as low energy utilization rate, small lighting field of view and difficult polarization modulation in the prior art are solved.
2 citations
Patent•
23 Nov 2018
TL;DR: In this article, the interference fringes of a local region of the surface to be measured are acquired and horizontally enlarged, and the surface height is obtained according to the horizontally-enlarged interference edges.
Abstract: The invention relates to a surface measurement method and a surface measurement device. The surface measurement method includes the steps following steps that: a surface to be measured is provided; the interference fringes of a local region of the surface to be measured are acquired and horizontally enlarged; and the surface height of the surface to be measured is obtained according to the horizontally-enlarged interference fringes of the local region of the surface to be measured. According to the surface measurement method, the local region is measured to characterize an overall condition under a premise that the frequency of the light source of the surface measurement device and the measuring mechanism of the surface measurement device are not changed, the number of measuring points cansatisfy the requirements of the Nyquist frequency of the local region, and therefore, the surface characteristics of a surface with large variations in surface height can be truly and accurately reflected. The surface measurement method can truly and accurately reflect the surface characteristics of a 2D cover plate and a 3D cover plate having large variations in surface height.
1 citations
Patent•
24 Sep 2019
TL;DR: In this article, a fan-shaped strip based mirror plane defect detection system and method is presented, which includes strip projection equipment, an image acquisition device, and a control module.
Abstract: The invention provides a fan-shaped strip based mirror plane defect detection system and method. The system includes strip projection equipment, an image acquisition device and a control module. The control module controls the strip projection equipment to project fan-shaped strips to a to-be-detected object. The image acquisition device is used for receiving a fan-shaped strip image reflected from the to-be-detected object and transmitting the acquired fan-shaped stirp image to the control module in a form of an image signal. The control module controls the strip projection equipment to output the fan-shaped strips by coding, decodes the fan-shaped strips acquired by the image acquisition device, solves a fan-shaped strip modulation degree by using data after decoding the fan-shaped strip image to obtain a gray-scale distribution map, and compares the data after decoding the gray-scale distribution map with the coded fan-shaped strip before output to obtain a modulation degree diagram and a defect display diagram that can observe defects.
References
More filters
Patent•
14 Mar 2003TL;DR: In this article, a system for dark field inspection of a semiconductor wafer was proposed, which includes a light source providing a beam, a traveling lens acousto-optic device (104) having an active region and responsive to an RF input signal to concurrently generate multiple traveling lenses in said active region, each lens having a focus, and the traveling lens being operative to receive the light beam and generate multiple spot beams at the respective focus of each of the generated traveling lenses.
Abstract: A system for dark-field inspection of a specimen, such as a semiconductor wafer (108), that uses a laser light source (101) for providing a beam of light. The system includes a light source (101) providing a beam, a traveling lens acousto-optic device (104) having an active region and responsive to an RF input signal to concurrently generate multiple traveling lenses in said active region, each lens having a focus, said traveling lens acousto-optic device (104) being operative to receive the light beam and generate multiple spot beams at the respective focus of each of the generated traveling lenses, said multiple spot beams scanning a first surface of said specimen, whereby a corresponding plurality of at least one of reflected beams and transmitted beams are generated; whereas at least one of reflected beams and transmitted beams comprises bright field and dark field components, and dark field optics for collecting and detecting the dark field component.
7 citations
Patent•
30 Apr 2003
TL;DR: In this article, the beam of the coherent source through the procedures of beam splitting, diffraction, fine tuning the direction, spatial filtering, light beam spacing transformation as well as focusing and magnifying is projected on the scene to obtain the structure light of the static stripes with intensity in sine distribution.
Abstract: In the invention, the beam of the coherent source through the procedures of beam splitting, diffraction, fine tuning the direction, spatial filtering, the light beam spacing transformation as well asfocusing and magnifying is projected on the scene to obtain the structure light of the static stripes with intensity in sine distribution. The two parallel beams after being split enter the two inputends of double acousto-optical modulators with the Bragg angle. The double acousto-optic modulators of the radio frequency signal in same frequency with 0-2 pi tunable phase difference are utilized to change the frequency of the signal in real time. The device includes the coherent source, the filter, the focusing lens and microscope objective.
7 citations
TL;DR: In this paper, a compact projection lens was designed to meet the requirements of interferometric fringes magnification for 3D fringe-based profilometry, which was shown to be adaptable for the mini LCoS (Liquid Crystal on Silicon) projector.
3 citations
Patent•
10 Dec 2014
TL;DR: An aspheric surface mold on-machine measuring device based on acousto-optic modulation comprises a laser, two beam expansion systems, beam shrinkage system, a beam splitter, a conversation lens, two optical flats, four round optical wedges with small wedge angles, a high-bandwidth acoustoelectric deflector, two spatial filters, two reflectors, a radio frequency power amplifier, a direct digital synthesizer (DDS), a CCD and a computer as discussed by the authors.
Abstract: An aspheric surface mold on-machine measuring device based on acousto-optic modulation comprises a laser, two beam expansion systems, a beam shrinkage system, a beam splitter, a conversation lens, two optical flats, four round optical wedges with small wedge angles, a high-bandwidth acousto-optic deflector, two spatial filters, two reflectors, a radio frequency power amplifier, a direct digital synthesizer (DDS), a CCD and a computer. In the device, the DDS and the CCD are both connected with the computer and controlled by the computer. DDS frequency control words are adjusted through computer programs, so that high-speed frequency conversion of interference fringes is conducted, and fringe images are processed through a multi-frequency time series phase-unwrapping method; the fringe frequency conversion speed of the device reaches dozens of nanoseconds per frame so that surface shape on-machine detection of an aspheric surface optical mold can be achieved.
3 citations
Patent•
27 Jul 2016
TL;DR: In this article, a coplane degree measurement system based on ultrasonic grating, expand the system of restrainting, acousto-optic medium container, ultrasonic transducer, computer, triaxial moving platform, optic platform and CCD camera including laser lamp-house, signal generator, laser, laser lamp -house, sign generator, and all install optic platform is last.
Abstract: The utility model discloses a coplane degree measurement system based on ultrasonic grating, expand the system of restrainting, acousto -optic medium container, ultrasonic transducer, computer, triaxial moving platform, optic platform and CCD camera including laser lamp -house, signal generator, laser, laser lamp -house, signal generator, laser expand the system of restrainting, acousto -optic medium container and triaxial moving platform and all install optic platform is last, laser lamp -house, laser expand the system of restrainting and acousto -optic medium container and set gradually according to the order after to in the past optic platform is last, the left side of acousto -optic medium container sets up ultrasonic transducer, the right side of acousto -optic medium container is provided with the plane of reflection to be used for reflecting the ultrasonic wave, triaxial moving platform is used for placing the object that awaits measuring to its with await measuring object contact's plane as reference planes. The utility model discloses an ultrasonic grating's technique for it all has the improvement to measure area, precision and speed, can satisfy the requirement of high accuracy rapid survey.
2 citations