20891 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 anti-interfering method of short-range FMCW radar includes designing a set of pseudo-random code according to occasion of radar, distributing different pseudo-random code to different radar operated at different area, applying different pseudo-random code to modulate frequency start-point of FM emission signal for the same radar on each cycle, making frequency-mixture on received echo signal by utilizing emission signal, using filter to filter off interference signal and applying FM signal processing means to treat reserved usable signal for obtaining object distance and speed information in high resolution.

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 belongs to the field vehicle active safety, and particularly discloses a detection method and system, based on laser radar and binocular camera, for a pedestrian in front of vehicle. The method comprises the following steps: collection data of the front of the vehicle through the laser radar and the binocular camera; respectively processing the data collected by the laser radar and the binocular camera, so as to obtain the distance, azimuth angle and speed value of the pedestrian relative to the vehicle; correcting the information of the pedestrian through a Kalman filter. The method comprehensively utilizes a stereoscopic vision technology and a remote sensing technology, integrates laser radar and binocular camera information, is high in measurement accuracy and pedestrian detection accuracy, and can effectively reduce the occurrence rate of traffic accidents.

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.

Embodiments of the present invention generally relate to methods and apparatuses for the channel measurement and feedback of a multi-dimensional antenna array. Specifically, according to embodiments of the present invention, the primary inventive idea is to allow a base station equipped with a multi-dimensional antenna array to configure more than one class of CSI-RS, wherein each class of CSI-RS is for use in a channel measurement at the UE for a different dimension of the multi-dimensional antenna array. The base station then transmits the generated configuration information to the UE so that the UE may perform channel measurement specific to different dimensions, for example, by selecting different codebooks for the channel measurement for different dimensions. In this way, it is possible to increase the channel measurement precision of the multi-dimensional antenna array, reduce the measurement feedback overhead and improve the system performance.

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.

The invention discloses a method for implementing online tests of stream flow based on video images, and belongs to the technical field of non-contact open channel flow measurement. The method relates to a water flow tracing system, a water surface illuminating system, a video flow acquisition system, a camera calibrating system, an image processing system and a flow estimating system, trace particles are thrown in a flow measuring stream segment by the water flow tracing system, a camera shoots a water surface video stream, frames are extracted at fixed intervals and are processed digitally, the image processing system processes digital images according to ground control point coordinate information provided by the camera calibrating system, and finally, the stream flow is computed by the aid of the flow estimating system according to a flow rate and area method. By the aid of the method, complicity of stream flow measurement is reduced, simultaneously, high measurement precision can be guaranteed, and the stream flow can be dynamically monitored in extreme environments.

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.