10201 results about "Measurement precision" patented technology

Methods and system for noninvasive determination of tissue analytes utilize tissue properties as reflected in key features of an analytical signal to improve measurement accuracy and precision. Physiological conditions such as changes in water distribution among tissue compartments lead to complex alterations in the measured analytical signal of skin, leading to a biased noninvasive analyte measurement. Changes in the tissue properties are detected by identifying key features in the analytical signal responsive to physiological variations. Conditions not conducive to the noninvasive measurement are detected. Noninvasive measurements that are biased by physiological changes in tissue are compensated. In an alternate embodiment, the analyte is measured indirectly based on natural physiological response of tissue to changes in analyte concentration. A system capable of such measurements is provided.

The auxiliary safety operation equipment based on omnibearing computer vision includes an omnibearing vision sensor for acquiring omnibearing video information outside and inside the vehicle, and an auxiliary safety operation controller for detecting fatigue operation and warning on fatigue operation. The omnibearing vision sensor installed in the right of the driver's seat and connected to the auxiliary safety operation controller detects the facial state, eye state and mouth state of the driver and the steering wheel state, monitors the vehicle direction, speed, etc, and warns the fatigue operation in case of detecting fatigue operation state. The present invention detects the characteristic parameter of fatigue operation state, and has high judgment precision and high measurement precision.

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.

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.

A chemical-sensing apparatus is formed from the combination of a chemical preconcentrator which sorbs and concentrates particular volatile organic chemicals (VOCs) and one or more chemiresistors that sense the VOCs after the preconcentrator has been triggered to release them in concentrated form. Use of the preconcentrator and chemiresistor(s) in combination allows the VOCs to be detected at lower concentration than would be possible using the chemiresistor(s) alone and further allows measurements to be made in a variety of fluids, including liquids (e.g. groundwater). Additionally, the apparatus provides a new mode of operation for sensing VOCs based on the measurement of decay time constants, and a method for background correction to improve measurement precision.

The invention discloses a method for measuring a geometric error parameter value of a rotary oscillation axis of a five-axis linkage numerical control machine tool. The method comprises the following steps of: measuring displacement errors of X, Y and Z directions on at least three positions under different rotating angles of the rotary oscillation axis respectively by using a ballbar, wherein translation axis linkage coordinates provided by a revolving tool central point (RTCP) cutter central point movement control function of a five-axis machine tool serve as measurement datum; and performing data processing according to the displacement errors to identify and calculate the geometric error of each rotating angle of the rotary oscillation axis. The rotary oscillation axis is measured independently by the method, so the geometric error value of the five-axis linkage numerical control machine tools of various structures at each rotary oscillation angles can be obtained. The method is not limited by the structures of the machine tools, is convenient to arrange and has high measuring precision.

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.

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.

Methods and systems for optimizing measurement system parameter settings of an x-ray based metrology system are presented. X-ray based metrology systems employing an optimized set of measurement system parameters are used to measure structural, material, and process characteristics associated with different semiconductor fabrication processes with greater precision and accuracy. In one aspect, a set of values of one or more machine parameters that specify a measurement scenario is refined based at least in part on a sensitivity of measurement data to a previous set of values of the one or more machine parameters. The refinement of the values of the machine parameters is performed to maximize precision, maximize accuracy, minimize correlation between parameters of interest, or any combination thereof. Refinement of the machine parameter values that specify a measurement scenario can be used to optimize the measurement recipe to reduce measurement time and increase measurement precision and accuracy.

An image processing device is provided that can precisely measure the photographing position or posture of a photographing device or the coordinates of an object based on sequentially changing photographed images. A series of sequentially photographed images are acquired, from which feature points are extracted. The feature points are tracked and correlated to each other. Stereo images are selected from the series of photographed images correlated, and subjected to an orientation and a 3D measurement. The error range of corresponding points obtained by the 3D measurement is calculated. Based on the calculated error range, it is determined whether or not the corresponding points are appropriate for 3D measurement. Those corresponding points determined as inappropriate are deleted. Another orientation and another 3D measurement are performed using those corresponding points excluding the deleted ones, thus improving the measurement precision.

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.

The invention relates to the technical field of gait analysis in biomedical engineering and provides a human gait analyzing method and system based on multi-sensor fusion. The method comprises the steps of filtering sensor signals to eliminate the signal noise error according to human motion features, and eliminating the integral error by means of the improved zero velocity updating algorithm, so that the method and system can be adapted to different walking scenes; fusing multiple sensor data with the Denavit-Hartenberg method, and reducing the leg position calculation error; calculating the step speed, step length, step frequency, walking period and walking track of a tested person accurately during walking after error correction is conducted; establishing a gait database, and conducting statistic analysis on gait data of different tested persons with the quantile regression analysis method. By the adoption of the method and system, gait parameter measurement precision can be improved, and gait parameters of different tested persons are comparable through standardization.

A method for improving the measurement accuracy of a portable coordinate measurement machine which comprises an articulated arm having jointed arm segments is presented. This method includes sensing deformation of a portion of the articulated arm when the arm is placed under a load, this deformation causing an error in the measurement made by the CMM, and correcting such error in response to the sensed deformation.

Methods are provided for deriving a partially continuous dependency of metrology metric(s) on recipe parameter(s), analyzing the derived dependency, determining a metrology recipe according to the analysis, and conducting metrology measurement(s) according to the determined recipe. The dependency may be analyzed in form of a landscape such as a sensitivity landscape in which regions of low sensitivity and/or points or contours of low or zero inaccuracy are detected, analytically, numerically or experimentally, and used to configure parameters of measurement, hardware and targets to achieve high measurement accuracy. Process variation is analyzed in terms of its effects on the sensitivity landscape, and these effects are used to characterize the process variation further, to optimize the measurements and make the metrology both more robust to inaccuracy sources and more flexible with respect to different targets on the wafer and available measurement conditions.

Electrodynamic on funnels confine, guide, or focus ions in gases using the Dehmelt potential of oscillatory electric field. New funnel designs operating at or close to atmospheric gas pressure are described. Effective on focusing at such pressures is enabled by fields of extreme amplitude and frequency, allowed in microscopic gaps that have much higher electrical breakdown thresholds in any gas than the macroscopic gaps of present funnels. The new microscopic-gap funnels are useful for interfacing atmospheric-pressure ionization sources to mass spectrometry (MS) and on mobility separation (IMS) stages including differential IMS or FAIMS, as well as IMS and MS stages in various configurations. In particular, “wedge” funnels comprising two planar surfaces positioned at an angle and wedge funnel traps derived therefrom can compress on beams in one dimension, producing narrow belt-shaped beams and laterally elongated cuboid packets. This beam profile reduces the ion density and thus space-charge effects, mitigating the adverse impact thereof on the resolving power, measurement accuracy, and dynamic range of MS and IMS analyzers, while a greater overlap with coplanar light or particle beams can benefit spectroscopic methods.

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.

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.

What is disclosed is a video-based system and method for estimating heart rate variability from time-series signals generated from video images captured of a subject of interest being monitored for cardiac function. In a manner more fully disclosed herein, low frequency and high frequency components are extracted from a time-series signal obtained by processing a video of the subject being monitored. A ratio of the low and high frequency of the integrated power spectrum within these components is computed. Analysis of the dynamics of this ratio over time is used to estimate heart rate variability. The teachings hereof can be used in a continuous monitoring mode with a relatively high degree of measurement accuracy and find their uses in a variety of diverse applications such as, for instance, emergency rooms, cardiac intensive care units, neonatal intensive care units, and various telemedicine applications.

The invention is intended to provide a position measuring system for a working machine, which can accurately measure the position of a monitoring point and can ensure high working efficiency even when measurement accuracy of a machine-equipped GPS has changed. A panel computer (45) computes the position of the monitoring point, which is set on an operating mechanism, in a three-dimensional space based on values measured by GPS receivers (43, 44) and angle sensors (21, 22, 23). When measurement accuracy of at least one of at least two GPS receivers lowers, the panel computer (45) corrects the computation for the position of the monitoring point based on a yaw angle measured by a gyroscope (25) for measuring the yaw angle of a machine body.

The invention discloses a method for measuring positioning points based on a laser tracker in a docking process of airplane parts. The method provided by the invention comprises the following steps of 1, establishing a model of transformation between an airplane global coordinate system and a laser tracker measure coordinate system according to common observation points, 2, acquiring current calculating positions of positioning measure points of airplane parts according to a process joint sphere centre position, and 3, controlling and driving a laser tracker to search current accurate positions of the positioning measure points of the airplane parts from the current calculating positions according to a cross helical search method and to carry out automatic measure. The method provided by the invention has the advantages that 1, an advanced laser measure technology is adopted so that the airplane assembling measure precision is improved; and 2, a measure process does not need artificial light introduction and full automatic search measure of a docking assembling process is realized according to an algorithm so that working efficiency and measure precision are greatly improved and working strength of workers is reduced.

The invention discloses a double rood beam high-sensitivity six-dimensional moment sensor in the technical field of robots. The double rood beam high-sensitivity six-dimensional moment sensor comprises two rood beams, two dead rings, one outer ring, and a plurality of resistance strain gages; a first rood beam and a second rood beam are arranged outside the outer ring respectively and are used as elastic bodies of the sensor for sensing stress; two dead rings are arranged outside the first rood beam and the second rood beam respectively; the resistance strain gages are adhered to the rood beams; each of the rood beams consists of four identical double-hole parallel sub beams; each double-hole parallel sub beam is provided with an I-shaped through hole; and a center hole is formed in the geometric center of each rood beam. In the double rood beam high-sensitivity six-dimensional moment sensor, floating beams used by the conventional six-dimensional moment sensor and crosstalk caused by the floating beams are removed, multi-component coupling is reduced conveniently and the measurement accuracy is improved.

The invention relates to the technical field of computer vision, and discloses a volume measurement method and system based on a depth camera. The method includes the steps: acquiring depth images with objects to be measured from the depth camera; extracting the objects to be measured from the depth images according to depth information to obtain target areas of the objects to be measured; converting two-dimensional image coordinates of pixels in the target areas of the objects to be measured to three-dimensional coordinates under a three-dimensional camera coordinate system by the aid of pre-calibrated parameters of the depth camera; calculating heights and lengths and widths of the objects to be measured according to the three-dimensional coordinates of the objects to be measured under the three-dimensional camera coordinate system, and calculating volumes of the objects to be measured. The depth images comprise depth information of the objects to be measured. The method is high in measuring accuracy and simple and convenient to use and can not be affected by shooting angles and heights, and mounting heights and angles of the camera cannot be calibrated.

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.

A height measuring apparatus and a bioinstrumentation apparatus with a height measuring device are provided capable of precise measurement accuracy without being affected by an examinee and being highly convenient to assemble, handle and operate. A height detector (a transceiver and a reflector or a transmitter and a receiver having a communication conformation with a laser or ultra sonic beam) has components arranged in a movable part (a head-contact arm or a movable bar) and in a stationary part (a height measurement unit (base platform) or a fixed bar) of a telescoping height measurement bar such that a communication signal route between the parts is not blocked when an examinee is standing thereon, to obtain a height measurement by detecting the distance between the movable and stationary parts.

The invention relates to a geometric parameter visual measurement method for a large composite board, and belongs to the field of visual measurement. By means of the method, on-site quick three-dimensional reconstruction and geometric parameter measurement of the large composite board can be achieved. According to the method, a binocular vision measurement system, a laser tracker system and an indoor Bluetooth locating system are used for measurement, feature points are distributed on the measured composite board, and reflection targets are pasted to the feature points; the binocular vision measurement system is set up and is composed of a left camera, a right camera, a continuous line laser and an automatic position control platform; the laser tracker system is arranged, and the indoor Bluetooth locating system is mounted, so that measurement is completed. By means of the method, visual calibration of the large composite board can be quickly and precisely achieved, splicing precision of adjacent images is improved, data measurement precision is improved on the whole, and the defects that a traditional measurement method is low in efficiency, precision and stability are overcome.

A simulation device displays a three-dimensional model of a robot system on a display device and simulates a robot system including a robot and an image pickup camera. The simulation device includes a display device for displaying a three-dimensional virtual space on a screen, a camera position determination unit for determining an installation position of the image pickup camera based on an image pickup range designated by the operator, optical characteristic information of the used image pickup camera, and required measurement precision, and a virtual image generator unit for generating a virtual image to be obtained by the image pickup camera based on the position of the image pickup camera in the three-dimensional virtual space and the optical characteristic information, thereby facilitating the determination of the suitable position of the image pickup camera and adjustment of the detection parameters.

This invention belongs to measuring technique field and relates to improvement for space round geometry parameters non-contact measuring method. This invention can calculate eh real three dimensional coordinates of round fringe by use of polar line restriction and calculate space round geometry parameters based on space round optimal fit. This invention reduces the measuring error caused by shape distortion of space round perspective projecting and increases the measuring accuracy of round geometry parameters based on the optical method. When the surface of space round to be measured is angle more than fifty degrees, the repeatability accuracy 3sigma of space round geometry center is superior to minus or plus 0.01 mm.

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.

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.

Motion capture system with a motion capture element that uses two or more sensors to measure a single physical quantity, for example to obtain both wide measurement range and high measurement precision. For example, a system may combine a low-range, high precision accelerometer having a range of −24 g to +24 g with a high-range accelerometer having a range of −400 g to +400 g. Data from the multiple sensors is transmitted to a computer that combines the individual sensor estimates into a single estimate for the physical quantity. Various methods may be used to combine individual estimates into a combined estimate, including for example weighting individual estimates by the inverse of the measurement variance of each sensor. Data may be extrapolated beyond the measurement range of a low-range sensor, using polynomial curves for example, and combined with data from a high-range sensor to form a combined estimate.