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30 results about "Holographic interferometry" patented technology

Holographic interferometry (HI) is a technique which enables static and dynamic displacements of objects with optically rough surfaces to be measured to optical interferometric precision (i.e. to fractions of a wavelength of light). These measurements can be applied to stress, strain and vibration analysis, as well as to non-destructive testing and radiation dosimetry. It can also be used to detect optical path length variations in transparent media, which enables, for example, fluid flow to be visualised and analyzed. It can also be used to generate contours representing the form of the surface.

Method for measuring liquid phase diffusion coefficient, and apparatus thereof

The invention relates to a method for measuring a liquid phase diffusion coefficient, and an apparatus thereof, and belongs to a method for measuring a diffusion coefficient of a liquid by adopting yellow light LED as a light source based on a capillary imaging method. According to the present invention, a transparent capillary is adopted to construct a liquid phase diffusion cell; the specific refractive index spatial resolution measurement capability of the capillary imaging method is adopted to directly observe and record the diffusion regularity of the thin layers of the diffusion medium in the capability, wherein the thin layers of the diffusion medium have the same refractive index; the liquid phase diffusion coefficient is calculated based on the Fick second law. With the present invention, the diffusion coefficient between glycerol and purified water is measured at a room temperature of 25 DEG C, with comparing the diffusion coefficient 0.720*10<-5> cm<2>/s reported by the literature of the traditional holographic interferometry method with the diffusion coefficient 0.715*10<-5> cm<2>/s measured by the method of the present invention, the relative error is 0.69%; the capillary is adopted to construct the liquid phase diffusion cell, such that the amount of the required sample is less, the measurement speed is rapid, the anti-interference capability is strong and the system stability is good.
Owner:YUNNAN UNIV

Device and method for detecting topological charge number of vortex beams based on improved Mach-Zehnder interferometer

The invention relates to a device and method for detecting the topological charge number of vortex beams based on an improved Mach-Zehnder interferometer, and belongs to the technical field of digital holography. The device comprises a semiconductor laser unit, a microscope objective spatial fiber, a collimating lens, a beam splitter prism I, a plane mirror, a beam splitter prism II, a spatial light modulator, a beam splitter prism III, a beam splitter prism IV and a photoelectric coupled device. According to the method, one arm of the device is used for generating the vortex beams to be used as object light, the other arm of the device is used for generating the vortex beams to be used as reference light, the holographic interferometry principle is used for recording the wave front phase information of the vortex beams in an interference fringe mode, phase distribution is digitally reconstructed in the later period, and the topological charge number of the vortex beams can be obtained according to the reconstructed phase distribution in accordance with the definition of the vortex beams. The device and method solve the problem that at present, specific instruments or equipment is needed in the method for detecting the topological charge number of the vortex beams, or an existing detecting method is complex to operate, poor in stability and low in reliability.
Owner:KUNMING UNIV OF SCI & TECH

Calibration method for rotation axis of holographic interferometric four-axis measuring device

The invention relates to a calibration method for the rotation axis of a holographic interferometric four-axis measuring device. The error of fitting which is realized by means of the center of a standard ball is large, and as a result, the problem of inaccurate calibration of a rotation axis is brought about, while, with the measuring device of the invention adopted, the problem can be solved. The method is realized by means of a binocular stereoscopic image sensor and a planar target with a standard point. The method includes the following steps that: 1, the images of a planar target in a set of different positions are acquired; 2, a holographic interferometric sensor obtains the three-dimensional point cloud data of the planar target in the set of different positions; 3, the planar fitting of the planar target is carried out; 4, a set of vectors of a fitted plane and the rotation center of the fitted plane are obtained, the calibration value of the rotation axis is determined; 5, arotation matrix R and a translation vector T between two coordinate systems are solved; and 6, and the calibration of the rotation axis is completed in a unified manner in a coordinate system. The calibration method of the invention has high precision and high efficiency.
Owner:HEILONGJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY

Method for measuring liquid phase diffusion coefficient, and apparatus thereof

The invention relates to a method for measuring a liquid phase diffusion coefficient, and an apparatus thereof, and belongs to a method for measuring a diffusion coefficient of a liquid by adopting yellow light LED as a light source based on a capillary imaging method. According to the present invention, a transparent capillary is adopted to construct a liquid phase diffusion cell; the specific refractive index spatial resolution measurement capability of the capillary imaging method is adopted to directly observe and record the diffusion regularity of the thin layers of the diffusion medium in the capability, wherein the thin layers of the diffusion medium have the same refractive index; the liquid phase diffusion coefficient is calculated based on the Fick second law. With the present invention, the diffusion coefficient between glycerol and purified water is measured at a room temperature of 25 DEG C, with comparing the diffusion coefficient 0.720*10<-5> cm<2> / s reported by the literature of the traditional holographic interferometry method with the diffusion coefficient 0.715*10<-5> cm<2> / s measured by the method of the present invention, the relative error is 0.69%; the capillary is adopted to construct the liquid phase diffusion cell, such that the amount of the required sample is less, the measurement speed is rapid, the anti-interference capability is strong and the system stability is good.
Owner:YUNNAN UNIV

Aspherical Surface Interferometry System and Method Based on Spatial Light Modulator Reference Surface

ActiveCN107421436BHigh design and manufacturing precision requirementsHigh precisionUsing optical meansSpatial light modulatorWavefront
The invention proposes a system and a method for measuring aspheric interference based on reference surface of a spatial light modulator, relating to an interferometry system and an interferometry method for measuring the aspheric surface shape and belonging to the field of photoelectric detection. The measuring system of the invention comprises a laser, a collimating objective, a spectroscope, a reference lens, a compensator, a to-be-measured aspheric surface, an imaging objective and a CCD detector. The SLM is used as the reference lens for an aspheric interferometry system, defined as an SLM reference lens. The present invention also discloses a measuring method using an aspheric interferometry system. The technical problem to be solved in the present invention is to generate a non-planar wavefront equal to a partially compensated aspheric wavefront and achieves zero-interference measurement. While the system and the method inherit the advantages of the partially compensating method that requires lower precision on the designing and manufacturing of the compensator, the advantage of high accuracy of the zero-compensation interferometry method is also maintained. In addition, it is possible to avoid the introduction of mechanical phase shift error in a traditional interferometry system.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

A method for calibrating the rotation axis of a holographic interference four-axis measuring device

The invention relates to a calibration method for the rotation axis of a holographic interferometric four-axis measuring device. The error of fitting which is realized by means of the center of a standard ball is large, and as a result, the problem of inaccurate calibration of a rotation axis is brought about, while, with the measuring device of the invention adopted, the problem can be solved. The method is realized by means of a binocular stereoscopic image sensor and a planar target with a standard point. The method includes the following steps that: 1, the images of a planar target in a set of different positions are acquired; 2, a holographic interferometric sensor obtains the three-dimensional point cloud data of the planar target in the set of different positions; 3, the planar fitting of the planar target is carried out; 4, a set of vectors of a fitted plane and the rotation center of the fitted plane are obtained, the calibration value of the rotation axis is determined; 5, arotation matrix R and a translation vector T between two coordinate systems are solved; and 6, and the calibration of the rotation axis is completed in a unified manner in a coordinate system. The calibration method of the invention has high precision and high efficiency.
Owner:HEILONGJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY

A device and method for detecting the inner wall of an engine cylinder based on digital holographic interference

The invention discloses a device and method for detecting the inner wall of an engine cylinder based on digital holographic interferometry. The device comprises a dual-frequency laser, a beam expanding/collimating optical path, a beam splitting plate, a phase shifter, a conical surface reflecting mirror, a scanning motion device, a CCD camera and an upper computer. The optical principle, devices and optical path arrangement of the device are similar to those of a Tyman-Green interferometer. The device introduces the 90-degree conical reflecting mirror, so that a straight incident light beam isconverted into a radial light beam. The radial measurement light beam irradiates on the inner wall of an engine to be detected so as to form an annular light band, and the light band is a to-be-detected surface participating in the interference. The device drives the conical reflecting mirror to move in a straight line introducing the scanning motion device so as to complete the detection for thewhole inner wall. The device is high in measurement accuracy and good in real-time performance and meets a requirement of high efficiency of online detection. The device belongs to non-contact measurement and avoids scratches caused by a contact for the inner wall; and the device has the advantages of surface measurement, large measurement range, much measurement information and the like.
Owner:UNIV OF SCI & TECH OF CHINA

A Method for Measuring Topological Charge Number of Vortex Beam Based on Improved Mach-Zehnder Interferometer

The invention relates to a device and method for detecting the topological charge number of vortex beams based on an improved Mach-Zehnder interferometer, and belongs to the technical field of digital holography. The device comprises a semiconductor laser unit, a microscope objective spatial fiber, a collimating lens, a beam splitter prism I, a plane mirror, a beam splitter prism II, a spatial light modulator, a beam splitter prism III, a beam splitter prism IV and a photoelectric coupled device. According to the method, one arm of the device is used for generating the vortex beams to be used as object light, the other arm of the device is used for generating the vortex beams to be used as reference light, the holographic interferometry principle is used for recording the wave front phase information of the vortex beams in an interference fringe mode, phase distribution is digitally reconstructed in the later period, and the topological charge number of the vortex beams can be obtained according to the reconstructed phase distribution in accordance with the definition of the vortex beams. The device and method solve the problem that at present, specific instruments or equipment is needed in the method for detecting the topological charge number of the vortex beams, or an existing detecting method is complex to operate, poor in stability and low in reliability.
Owner:KUNMING UNIV OF SCI & TECH

Digital holographic interferometry and frequency-variable projection fringe compound measurement system and method

The invention discloses a digital holography interference and variable frequency projection stripe duplex measurement system and method and belongs to the technical field of photoelectric measurement. The system comprises a set of continuous variable angle digital holography interference measuring device or a variable wave length digital holography interference measuring device and a set of multi-step variable frequency projection stripe measuring device. A multi-step variable frequency projection stripe measuring method is firstly used for roughly measuring an object to be measured so as to obtain a rough height range, and then the continuous variable angle digital holography interference measuring device or the variable wave length digital holography interference measuring device is used for precisely measuring the object to be measured so as to obtain the height information of all points of the object. According to the digital holography interference and frequency-changing projection stripe duplex measurement system and method, all the points of the object to be measured are measured independently in the measuring process, the phase unwrapping step is not needed, the surface type parameters of objects which are complex in shape and discontinuous can be measured, and compared with the unique multi-step variable frequency projection stripe measurement and the continuous variable angle digital holography interference or the variable wave length digital holography interference, the digital holography interference and frequency-changing projection stripe duplex measurement system and method have the advantage of being capable of meeting the requirement for high-precision measurement and the requirement for a large variation range of measuring heights at the same time.
Owner:XI AN JIAOTONG UNIV +1
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