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705results about How to "Quick measurement" patented technology

Full-field three-dimensional measurement method

A method and system for full-field fringe-projection for 3-D surface-geometry measurement, referred to as “triangular-pattern phase-shifting” is disclosed. A triangular grey-scale-level-coded fringe pattern is computer generated, projected along a first direction onto an object or scene surface and distorted according to the surface geometry. The 3-D coordinates of points on the surface are calculated by triangulation from distorted triangular fringe-pattern images acquired by a CCD camera along a second direction and a triangular-shape intensity-ratio distribution is obtained from calculation of the captured distorted triangular fringe-pattern images. Removal of the triangular shape of the intensity ratio over each pattern pitch generates a wrapped intensity-ratio distribution obtained by removing the discontinuity of the wrapped image with a modified unwrapping method. Intensity ratio-to-height conversion is used to reconstruct the 3-D surface coordinates of the object. Intensity-ratio error compensation involves estimating intensity-ratio error in a simulation of the measurement process with both real and ideal captured triangular-pattern images obtained from real and ideal gamma non-linearity functions. A look-up table relating the measure intensity-ratio to the corresponding intensity-ratio error is constructed and used for intensity-ratio error compensation. The inventive system is based on two-step phase-shifting but can be extended for multiple-step phase-shifting.
Owner:UNIVERSITY OF WATERLOO

Method for measuring object deformation in real time

The invention discloses a method for measuring object deformation in real time, which comprises the following steps: arranging and adjusting measuring equipment, namely symmetrically arranging two cameras and corresponding LED illumination lamps above a measured object, and making optical axes of the two cameras intersected in a distance of 1 meter in front of the cameras; then calibrating the cameras, namely tightly sticking mark points to the surface of an object to be measured according to the size and shape of the measured object and the measurement requirement; next, placing the measured object stuck with the mark points under the two cameras in about 1 meter or moving the whole measuring equipment to make the measured object enter a measurement range and enable each camera to acquire the mark points on the surface of the measured object, starting the two cameras to shoot sequence images, and acquiring digital images; then identifying and positioning the images; reversely solving a projection matrix according to the calibration result of the cameras, and combining image coordinates of the solved mark points on the surface of the measured object on the images of the two cameras to reconstruct a three-dimensional coordinate of the mark points; and finally, carrying out deformation analysis and calculation for the mark points on the surface of the measured object.
Owner:XI AN JIAOTONG UNIV

Calibration technology for multiple structured light projected three-dimensional profile measuring heads

The invention relates to a calibration technology for multiple structured light projected three-dimensional profile measuring heads, discloses a technology for calibrating multiple structured light projected three-dimensional profile measuring heads in different directions, which can be used for the quick label-free measurement of an object profile projected by structured light, and belongs to the technical field of optical measurement. In the calibration technology, only a calibration object of a plane with a plurality of calibration patterns is required to be designed and is not required to be manufactured into a high-precision three-dimensional target with known geometrical relationships on all surfaces; and geometrical parameters among all planes of the calibration object can be obtained by a close-range photogrammetry technology to upgrade the calibration object into the three-dimensional target, so the difficulty of machining and maintaining the high-precision three-dimensional target directly is reduced. By utilizing the technology, multiple structured light projected three-dimensional profile measuring heads can be measured from different visual angles in a label-free mode, and point clouds scanned in different directions are unified to one coordinate system automatically, so error accumulation caused by splicing is avoided effectively, and the time of the three-dimensional appearance reconstruction of the object can be shortened.
Owner:SOUTHWEAT UNIV OF SCI & TECH

Multi-wavelength interference real-time absolute distance measurement device on the basis of femtosecond optical comb synchronization frequency locking

InactiveCN105589074APreserve precisionExpanding the Unambiguous Measurement Range of RangingElectromagnetic wave reradiationHeterodyne interferometerMeasurement precision
The present invention provides a multi-wavelength interference real-time absolute distance measurement device on the basis of femtosecond optical comb synchronization frequency locking. The multi-wavelength interference real-time absolute distance measurement device on the basis of femtosecond optical comb synchronization frequency locking comprises: a multi-wavelength generator on the basis of the femtosecond optical comb synchronization frequency locking configured to emit a plurality of high-frequency stable object wavelength lasers; a heterodyne interferometer configured to receive lasers outputted by the multi-wavelength generator after the femtosecond optical comb synchronization frequency locking, returning measurement light and reference light after generation of interference through the heterodyne interferometer being coupled in single mode fibers by lens focusing to form mixed multi-wavelength heterodyne interference signals; and a synchronization phase demodulation module configured to separate the mixed multi-wavelength heterodyne interference signals obtained by the heterodyne interferometer through wavelength demodulation to obtain interference signals corresponding to each wavelength and perform synchronization phase measurement processing of the interference signals corresponding to each wavelength to finally obtain an accurate absolute distance value. The multi-wavelength interference real-time absolute distance measurement device on the basis of femtosecond optical comb synchronization frequency locking is high in traceability of values, high in measurement precision, large in non-fuzziness measuring range, fast in update rate and easy to measurement on site in real time, and is applicable to the fields of the industrial production, the equipment manufacture and the large-size precision measurement.
Owner:NAT UNIV OF DEFENSE TECH

Tricolor raster projection-based Fourier transform three-dimensional measuring method

The invention discloses a new tricolor raster projection-based Fourier transform three-dimensional measuring method, which mainly aims to accurately work out the phase distribution of raster images, and then obtain the three-dimensional topography information of objects according to the phase distribution. The method is implemented through the steps of setting the gray values of R and G components in a projected raster to follow a sinusoidal variation regulation with two different frequencies, and setting a B component as the average value of the R component or the G component, and forming a color raster image to be projected on an object to be measured; and separating the three components of an acquired deformed color raster image, then processing the separated three gray images, meanwhile, restraining background components and high-frequency noises when the Fourier transform is used to calculate relative phases, and carrying out comparison and calibration on the three gray images with the relative phase values under the two frequencies when the phases are unwrapped so as to achieve the purpose of precisely calculating absolute phases containing height information. Only one raster image is required to be projected in the whole measuring process, therefore, the method of the invention is good in real-time.
Owner:HAIAN COUNTY SHENLING ELECTRICAL APPLIANCE MFG +1

Biological tissue moisture measurement device and method based on terahertz wave attenuated total reflectance (ATR)

InactiveCN102590125AOvercome the disadvantages of complex preparationAvoid Destructive AnalysisColor/spectral properties measurementsMeasurement deviceFrequency conversion
The invention relates to non-linear optical frequency conversion and the application of the non-linear optical frequency conversion and provides a method and a device which can widen the preparation requirements for a biological sample, do not need preparation of the sample, are high in measurement sensitivity, and can achieve high resolution, fast and real-time biological sample moisture content and distribution imaging measurement. The technical scheme is that the biological tissue moisture measurement device based on terahertz wave attenuated total reflectance (ATR) is composed of a tunable terahertz (THz) radiation source, a non-spherical face lens assembly, a total reflection prism, a two-dimensional mobile scanning platform, a terahertz wave detector and a computer. The total reflection prism is placed in the middle of the non-spherical face lens assembly, the face to be tested of a biological sample to be tested clings to the top face of the total reflection prism fixed on the two-dimensional mobile scanning platform, terahertz (THz) waves are projected to the terahertz detector through the non-spherical face lens assembly, and a detection result of the terahertz detector is output to the computer. The biological tissue moisture measurement device and the method based on the terahertz wave attenuated total reflectance (ATR) are mainly used for biological sample moisture content and distribution imaging measurement.
Owner:TIANJIN UNIV

High speed multi-dimensional vibration measuring device and method based on stripe target

The invention relates to a high speed multi-dimensional vibration measuring device and method based on a stripe target. The device comprises a stripe target, an imaging module, a signal control and processing module and a display module. The method includes the following steps: arranging the stripe target on a vibration structure to be measured; adopting an image module to conduct continuous imaging and recording on the stripe target; utilizing the imaging module to transmit the image of the stripe target to the signal control and processing module; utilizing the signal control and processing module to conduct Fourier transform on the stripes at the same position of the same stripe target in each frame of the image, adopting a certain peak value frequency correction method to accurate correct the peak value frequency, and then utilizing the imaging mathematical relation and the corrected peak value frequency to obtain a time domain curve with stripe target structure vibration, namely acquiring structure vibration signals through reduction; displaying an image processing result through a display module or conducting further data processing through vibration signals. By means of the device and method, vibration measurement of points, lines and faces in certain range is achieved, the measurement speed is high, and the accuracy is high.
Owner:FUZHOU UNIV

Multi-wavelength tunable micro-interference measuring method and device thereof

The present invention discloses a multi-wavelength tunable micro-interference measuring method and a device thereof. A multi-wavelength tunable laser is modulated to output three paths of wavelength tunable laser signals in the synchronous or time-sharing manner. The three paths of wavelength tunable laser signals are compounded as one path of composite laser signals through beam-combining optical fibers, and the path of composite laser signals is focused and coupled to the surface of a frosted glass plate which is rotating at a constant speed. After that, the path of composite laser signals is incident to the surface of a beam splitter after being formed as the parallel light through a collimating beam-expanding lens. The light is reflected to enter an interference microscope, and then is irradiated onto the surface of a to-be-tested element on an objective table. A reflected signal sequentially passes through the objective lens of the interference microscope and the beam splitter to be coupled to the target surface of a color camera through an imaging lens. Finally, output signals are regulated and acquired data are synchronously controlled by a computer. According to the technical scheme of the invention, a plurality of different wavelengths are adopted by a single-wavelength tunable laser module, so that the optical phase shift and the multi-wavelength interference detection are realized. The method and the device are especially suitable for the fast and accurate measurement of microstructure elements which are complex and non-continuous in surface shape variation. Therefore, measurement errors, caused by the scanning motion of a mechanical component, can be effectively inhibited.
Owner:SUZHOU UNIV

Method for automatically detecting and evaluating color of laser beam emitting paper and quality of laser beams

The invention relates to a method for automatically detecting and evaluating the color of a piece of laser beam emitting paper and the quality of laser beams. The method comprises the following steps: putting and fixing a piece of laser beam emitting paper to be detected on a measuring platform by adopting an automatic detection system; setting the number of measuring points and the measuring step length of a color measuring instrument in the horizontal and vertical directions on the measuring platform; controlling the displacing, positioning and measuring of the color measuring instrument in the horizontal and vertical directions automatically, and reading the color information of the measured sample in different positions; analyzing and calculating the chromatic value by using a computer to obtain the CIELAB or CIEDE2000 color difference of the measured sample in different measuring positions; drawing a color difference distribution diagram, and detecting the color uniformity and rainbow cycle of the single laser beam emitting paper and the quality of laser beams according to the periodic distribution rule and the peak distribution rule of the color difference distribution diagram. By adopting the method provided by the invention, the problems of measurement value uncertainty and human error can be solved, and automatic detection can be realized. The method is easy and convenient to operate and can be used for measuring normatively with a small error.
Owner:BEIJING INSTITUTE OF GRAPHIC COMMUNICATION
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