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10201 results about "Measurement precision" patented technology

Measurement precision. The amount of variation that exists in the values of multiple measurements of the same factor. Greater precision means less variation between measurements. Measurement precision is not to be confused with measurement accuracy, which depends on the level of agreement between the measurement and a known standard.

Camera based six degree-of-freedom target measuring and target tracking device with rotatable mirror

An embodiment may comprise a camera based target coordinate measuring system or apparatus for use in measuring the position of objects in manner that preserves a high level of accuracy. This high level of measurement accuracy is usually only associated with more expensive laser based devices. Many different arrangements are possible. Other embodiments may comprise related methods of using a camera based target coordinate measuring method for use in measuring the position of objects. Many variations on the methods are possible. For example, a camera based coordinate measuring system for use in measuring the position of a target relative to at least one frame of reference without requiring use of a laser range finder for measuring distance may comprise at least three or more light sources located on a target wherein the light sources are located on the target at known three-dimensional coordinates relative to each other; at least one rotatable mirror rotatable on about a first axis and a second axis; a camera located to receive light emitted by the light sources that is reflected off the minor; two angular measuring devices to measure the angles of rotation of the mirror about the first and second axes; and a processor for determining up to three positional degrees of freedom and up to three rotational degrees of freedom of the target.

Distance measuring method applying binocular visual parallax error distance-measuring principle

The invention discloses a distance measuring method applying a binocular visual parallax error distance-measuring principle. By means of adopting different base length to adapt to requirements on measurement accuracy of different distance measuring ranges, the distance measuring method is applicable to precise size measurement for short distance and small parts. On the basis of a conventional binocular measuring method, a pair of cameras which are provided with parallel optical axes and positioned side by side are adopted to make two random to-be-measured visualized points in two images into a plane vertical to the two optical axes, depth values of the two to-be-measured points are obtained via a inversely proportional relationship between binocular visual parallax error and depth, distances from the two to-be-measured points to an optic center and angles among the two to-be-measured points and an optical center connection line can be determined according to the depth value of the to-be-measured points and focal length of the cameras, and then the actual distance between the two points can be determined via the cosine law. Compared with conventional methods, the distance measuring method applying the binocular visual parallax error distance-measuring principle has the advantages of simplicity in operation, strong practicability, high precision and easiness in popularization and use.

Circular target circular center positioning method

The invention discloses a circle center locating method of a circular target, mainly relating to a great deal of target identification and target location. Firstly, rough circle center location is carried out to an image by using a simple contour centroid method, a key square region is extracted as a region of interest according to the information of a rough location circle center and a rough location radius, and pixel-level edge location is carried out to the circular target in the region of interest by a canny operator; then sub-pixel location is carried out to the circular target according to the geometric features and the gray information of the circle, therefore, a precise coordinate of sub-pixel edge points is obtained; after that, a curvature filtering method and an average filtering method are respectively used for filtering 'isolated points' and noise occurring in the sub-pixel edge points; finally, a least squares method is utilized to fit a circle to the filtered sub-pixel edge points so as to obtain the final circular center and radius. The method not only effectively improves the precision of circle center location, but also improves the robustness thereof, thus further improving the measurement precision of a measurement system and perfecting the stability of the measurement system.
Owner:南通欧特建材设备有限公司 +1

Object three-dimensional contour outline measuring set and measuring method

ActiveCN101451826AUniform light intensity at the spectral pointImprove energy utilizationUsing optical meansInformation processingMeasurement device
An object three-dimensional outline measurement device and a measurement method are disclosed, the device is composed of a laser diode, a lens, an aperture diaphragm, a two-dimensional Dammam grating, a cylindrical mirror and an area array CCD camera, a transmission line and a computer, the connection relationship therebetween is as below: a beam emitted by the laser diode passes through the lens, the aperture diaphragm, the two-dimensional Dammam grating, and the cylindrical mirror sequentially to form one-dimensional projection array stripes, which illuminates the surface of an objective to be measured, the area array CCD camera collects the grating projection strips modulated by three-dimensional digital shape on the surface of the measured objective and outputs the strips to the computer via the transmission line, the computer includes an image collecting interface, image collecting software and three-dimensional measurement information reconstruction algorithm software. The invention has, by utilizing the Fourier transform three-dimensional outline measurement structure, the advantages of high energy utilization rate, simple measurement structure, high measurement precision, convenient computer reconstruction information processing and great easiness for operation.

Optical measurement system and method for three-dimensional shape of large-scale complex curved surface member

ActiveCN106959080AIntegrity guaranteedGuaranteed measurement efficiencyUsing optical meansGratingData integrity
The invention provides an optical measurement system and method for a three-dimensional shape of a large-scale complex curved surface member. The method is based on binocular optical grating projection measurement technologies, point cloud poses of all station positions during multiple station position measurement are obtained via a laser tracker and a corresponding target ball, point cloud obtained via the multiple station position measurement is converted to be under a unified laser tracker coordinate system according to corresponding pose data, and overall merging of point cloud data of a large-scale complex surface-shaped member can be realized; in the system, a six degree-of-freedom robot is used as a carrier for a point cloud space pose tracking unit and a binocular structured light measurement device, single station position measurement precision is ensured via calibration of the binocular structured light measurement device before measurement work starts, and data integrity and measurement efficiency are ensured via measurement route planning. Via the optical measurement system and method, all kinds of large-scale complex surface-shaped members can be accurately measured in non-contact conditions; practical, reliable and complete original three dimensional shape data can be provided for evaluation of all kinds of processing quality.

Dynamic crack length measurement method for machine vision fatigue crack propagation test

The invention provides a dynamic crack length measurement method for a fatigue crack propagation test based on the machine vision technology. The method comprises the following steps: 1, performing machine vision crack measurement system calibration; 2, performing fatigue test, wherein a test piece with precracks begins to generate fatigue cracks along the direction of the precracks, and the fatigue cracks extend; 3, collecting crack images, wherein a mode of collecting single-face images of the test piece and a mode of collecting two-side images of the test piece are used in the fatigue crack propagation test; 4, reinforcing the collected images; 5, identifying the position of the trunk of cracks, as well as peaks and identifying directions of cracks by using the method of image analysis and crack identification; and 6, calculating the actual crack identifying length and crack length. The method has the advantages of simplifying the process and reducing work load; and by the method, the crack identifying process can be visually and accurately observed and recorded, the calculated crack length specified by the international standard can be measured accurately. The method also has the advantages of high measurement accuracy and good system anti-jamming performance.

Device and method for measuring swelling representation parameters of swelling soil

The invention discloses a device and method for measuring swelling representation parameters of swelling soil. The device for measuring the swelling representation parameters of the swelling soil comprises a sample container, a soil body permeation coefficient measurement part, a jacking cylinder applying a vertical load, a dial indicator for testing a swelling soil sample to generate vertical deformation, and a deformation pipe used for testing water seepage coefficients of the swelling soil. The method comprises the steps of: immersing the swelling soil sample into water for swelling stably, measuring the water seepage coefficients; and then electrically heating the swelling soil sample to ensure that the swelling soil sample is dehydrated and contracted stably, and measuring the permeation coefficients of the swelling soil. Therefore, the invention can be used for measuring water seepage and permeation coefficients of the swelling soil in a repeatedly-swelling deformation process by controlling temperature and water content changes of the swelling soil sample in the sample container so as to reflect the change of a fracture and a soil body structure inside the soil body of the swelling soil in the repeatedly-swelling deformation process. In addition, the sample container of the device is connected with an external pipeline through each joint arranged on the sample container, therefore, data measurement in an experiment process is facilitated, and measurement precision of data is increased.

Method and device for online detection of size of city rail train wheel set

The invention discloses a method and device for online detection of the size of a city rail train wheel set. A system is mainly comprises two 2D laser displacement sensors arranged along a train rail in a mirror symmetric mode, and two laser bijection switches arranged on the two sides of the same rail in a certain geometrical relation. The 2D laser displacement sensors detect and obtain tread contour lines, and the two laser bijection switches detect the wheel passing speed. The rim height and the rim thickness are worked out by extracting the tread contour lines of wheels passing through a detection system according to the geometrical relation. The coordinates of the lowest rim points of the detected tread contour lines of the wheels at different moments are extracted, the coordinates at the different moments are restored to coordinate values at the same moment on the condition that the speed is given, so that the circle where the top points of the rims of the wheels are located is fitted out, the two times of the height of the rims is subtracted from the diameter of the circle of the top points of the rims, and thus the diameters of the wheels are obtained. The method and device for online detection of the size of the city rail train wheel set are low in cost, simple in operation and high in non-contact type measurement precision.

Spatial circular geometric parameter binocular stereo vision measurement method

The invention discloses a spatial circle geometrical parameter dual-eye solid visual measurement method suitable for non-contact type online measurement of the spatial circle geometrical parameter of an industrial product, aiming at overcoming the existing problems of low measurement precision, slow measurement speed and low automation degree. The method is divided into a calibrating stage, an image processing stage and a spatial circle fitting stage. A neural network technique is firstly adopted to carry out the calibration of a camera; a dual-camera is utilized to carry out the extraction of sub-pixel image edges of the spatial circle, a simple algorithm is developed based on the image gray gradient distribution characteristic so as to realize the match of edge points, the practical 3D spatial coordinates of the circle edges are then obtained, and the geometrical parameters of the spatial circle comprise radius, position of center of circle and orientation of the plane where the spatial circle is arranged are gained by the fitting of the spatial circle with corresponding mathematical geometrical knowledge. The spatial circle geometrical parameter dual-eye solid visual measurement method has fast image processing speed and high automation degree, and has relative measurement error of the spatial circle of superior to plus or minus 0.6% when the plane where the spatial circle is arranged has an angle of about 50 DEG with the image plane.

Method for calibrating external parameters of monitoring camera by adopting reference height

InactiveCN102103747AImage analysisTerrainHorizon
The invention discloses a method for calibrating external parameters of a monitoring camera by adopting reference height, which comprises the following steps of: far vanishing point and lower vanishing point-based vision model description and related coordinate system establishment; projected coordinate calculation of reference plumb information-based far vanishing points and lower vanishing points in an image plane; reference height calibration-based camera height, overhead view angle and amplification factor calculation; design of a reference plumb direction-based horizon inclination angle calibration tool; and design and use of perspective projection model-based three-dimensional measurement software and three tools for three-dimensional measurement, namely an equal height change scale, a ground level distance measurement scale and a field depth reconstruction framework. The calibrating method is simple and convenient in operation, quick in calculation and high in measurement precision. The reference can be a pedestrian, furniture or an automobile; and a special ground mark line is not needed. The method allows the camera to be arranged at a low place, and the shooting overhead view angle is slightly upward as long as the bottom of the reference can be seen clearly in the video and the ground level coordinate system is definite.
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