160results about How to "Calculation stable" patented technology

The invention belongs to the field of numerical control machine tool dynamic error compensation and relates to a novel contour error estimation method, particularly to a curved surface tool path contour error compensation method based tool location point correction. The method comprises, on the basis of identifying the servo gain of a machining feed shaft control system, estimating practical machining points off line according to a following error model and linear interpolation machining codes; estimating contour error vectors according to a method similar to accumulated chord length parametric cubic spline of ideal tool paths; computing the contour error compensation according to the components of the contour error vectors on every axis to obtain compensated tool location points and further to generate linear interpolation numerical control machining codes for practical machining. The curved surface tool path contour error compensation method based tool location point correction can improve the dynamic precision of a numerical control machine tool and is high in precision, stable in computation, free from online measurement, easy to implement and wide in application range.

A long baseline satellite formation GNSS relative positioning method based on ambiguity fixing is provided in order to improve the success rate of ambiguity fixing and the accuracy of relative positioning results. According to the technical scheme, the method comprises the following steps: first, collecting and pre-processing input data, and determining the absolute general orbit of a formation satellite; then, eliminating the geometric distance and clock error in differential observation data, estimating a single-difference phase ambiguity float solution and a single-difference ionosphere delay parameter, carrying out double-difference transform to get a double-difference wide-lane ambiguity float solution and a covariance matrix, and fixing the double-difference wide-lane integer ambiguity and the double-difference narrow-lane integer ambiguity; and finally, outputting the relative positioning result of ambiguity fixing. By adopting the method of the invention, the problem that ambiguity fixing strongly depends on a pseudo code with low observation precision due to equally-weighted pseudo code and phase processing in M-W combination in the traditional method is avoided, the success rate of long baseline satellite formation GNSS relative positioning ambiguity fixing and the accuracy of final relative positioning results are improved, calculation is stable, and the reliability of relative positioning results is improved.

An image processing apparatus includes: an image obtaining device which obtains a breast image obtained by radiography of a breast; a mammary gland region extracting device which extracts a mammary gland region from the breast image; a local region setting device which sets a plurality of local regions around pixels belonging to the extracted mammary gland region; a local contrast value calculating device which calculates a plurality of local contrast values in a local regions, for each of the set plurality of local regions; and an image processing device which applies image processing to the breast image on the basis of the calculated plurality of local contrast values. Thus, considering a contrast between a mammary gland and a fat region, a stable image processing result can be obtained while enhancing viewability of a local mammary gland structure and a lesion.

A probabilistic estimation of fatigue crack life of a component is provided. A plurality of representations of the component is defined from material property scatter data and flaw-size scatter data, wherein each representation is defined by one possible material condition and flaw-size condition associated with the component. For each representation, a component location is selected and a determination is made whether said individual representation fails after a given number of cycles N, based on the calculation of a crack growth in the selected location. The crack growth is calculated on the basis of the material condition and the flaw-size condition in the selected location. Failure of the individual representation is determined if the crack growth is determined to be unstable. The sum total of the number of the representations that failed after N cycles is determined. A probability of failure of the component after N cycles is then determined.

Signals are fetched out from winding at secondary side of current transformer on each line so as to obtain detected currents in triphase after voltage conversion and isolation of high-ohmic resistor. Threshold measuring detected currents in triphase is carried out in order to determine fault lines, and functions of high-speed data correction and A/D conversion are started up. Characteristic data of defective form of traveling wave are picked up from the A/D converted data, which are labeled with time mark by high precision GPS device. Then, being sorted and matched according to lines, the labeled data are stored to memory in computer. Fault category is determined and fault distance is calculated out by using the said computer and dedicated application software to analyze and calculate characteristic data after multiple refractions and reflections in each line as well as time difference. The invention raises location accuracy, reliability, practibility and economical efficiency.

A motion calculation device includes an image-capturing unit configured to capture an image of a range including a plane and outputs the captured image, an extraction unit configured to extract a region of the plane from the image, a detection unit configured to detect feature points and motion vectors of the feature points from a plurality of images captured by the image-capturing unit at a predetermined time interval; and a calculation unit configured to calculate the motion of the host device based on both of an epipolar constraint relating to the feature points and a homography relating to the region.

The invention relates to a universal full-hardware one-step 1588 clock synchronization device and method. The device comprises a framing module, an MAC transmission control module, an MAC receiving control module, an analysis module, a timestamp generation module, a first-in first-out queue timestamp FIFO module, a local clock module, a deviation calculation module and a timestamp insertion module. The method of the invention includes the following steps: recording timestamp information, identifying synchronous messages, storing the timestamp information, identifying synchronous broadcast messages Sync, inserting the timestamp information, calculating the time deviation of master-slave clocks, and correcting the time of the slave clock. According to the scheme of the invention, a hardware-only one-step synchronization method is adopted, effective data signals ctrl at a reduced gigabit media independent interface (RGMII) between a data link layer MAC and a physical layer PHY are adoptedto collect accurate timestamp information, and thus the universality and synchronization accuracy of the system can be improved.

The invention discloses a method for establishing a communication relationship between oil deposit wells. The method comprises the steps of dividing communication units, wherein a communication area between the oil deposit wells is divided into multiple communication units, the connecting area between every two well points corresponds to one communication unit, and the characteristic parameter of each communication unit comprises an average conductivity and a pore volume; calculating the single-well water-cut, and the single-well water-cut of each well point is calculated according to the average conductivity and the pore volume of each communication unit; calculating production performance indexes, wherein according to the single-well water-cut of each well point, the production performance indexes are calculated; correcting parameters, wherein fitting is conducted on the calculated production performance index of each well point and an actual production performance index of the well point, and then correction is conducted on the average conductivity and the pore volume of each communication unit. By the adoption of the method, mutual action of the wells can be reflected, the conditions that wells are stopped and an oil well is converted into water injection are considered, and the actual geologic features of the whole oil deposit wells are also considered.

The invention relates to a precision discrete optical power flow calculation method of a VSC-HVDC (voltage source converter based high voltage direct current) containing AC/DC system. The calculation method is characterized by comprising the steps of firstly analyzing a power steady-state equation and other modified equations of the VSC-HVDC containing AC/DC system, then setting equality constraints and inequality constraints, and finally introducing a positive curvature quadratic penalty function into an interior point method. According to the calculation method, the interior point method is adopted to carry out optimization on continuous variables of the AC/DC system, the penalty function is introduced when a certain condition is reached, and discrete variables are constrained and optimized. Meanwhile, parameter values of the penalty function are continuously adjusted according to variations of the iteration quantity, and finally a purpose of optimizing the continuous variables and the discrete variables simultaneously is achieved.

The invention discloses a structural parameter identification method for a dynamic model of an accelerometer based on refined spectrum analysis, and belongs to the fields of information technology processing, measurement and control. Input and output data of the accelerometer is obtained and captured via an impact calibration experiment in an accelerometer absolute method; discrete Fourier transform is carried out on the obtained input and output data to determine estimation of frequency response of the accelerometer; the estimation of frequency response is analyzed to obtain a primary estimated value of the resonant frequency; a spectrum refining method is used to refine zones near the resonant frequency and the zero frequency, and the resonant frequency of the resonant amplitude and a secondary estimated value of the zero-frequency amplitude are obtained; and the relation between the model parameter and a secondary estimated value of the coordinate of a feature point is utilized to determine estimation of the structural parameter of the dynamic model of the accelerometer, and the structural parameter of the dynamic model of the accelerometer is identified based on refined spectrum analysis. According to the method, the process of parameter identification of the two-order dynamic order of the accelerometer is simplified, and the modeling and identification precision and calculation efficiency of the accelerometer in the frequency domain are improved.

The invention discloses an on-line test structure for Seebeck coefficient of a polysilicon-metal thermocouple. The technology is implemented in a way that: respectively measuring the actual temperature difference between the cold end and the hot end of the thermocouple in the thermal steady state by using two temperature measurement resistors, measuring the open-circuit voltage of the thermocouple pile, and carrying out simple calculation to obtain the Seebeck coefficient of the polysilicon-metal thermocouple. The test structure disclosed by the invention is simple and convenient to manufacture, and can be obtained by a common MEMS surface working technique, thereby avoiding complex suspended structure and body processing technique. The measured temperatures are actual temperatures of thehot end and the cold end of the thermocouple pile in the thermal steady state, and people do not need to consider the influence of radiation, convection and other factors; and thus, the test requirements are low, the test method and tested parameter values are stable, and the calculation is simple and reliable.

The embodiment of the invention provides a camera external parameter calibration method and device and electronic equipment, and the method comprises the steps: carrying out the distortion correctionof an original image of a calibration image based on the internal parameters of a camera, and obtaining a distortion correction image; obtaining pixel coordinates of four intersection points formed bythe four straight lines in the distortion correction image; and calibrating camera external parameters through a preset coordinate transformation strategy based on the pixel coordinates of the four intersection points. Through the scheme, the external parameter calibration speed of the camera and the accuracy of the calibration result can be improved.

The invention discloses a complex network theory-based water route vulnerability research method. The complex network theory-based water route vulnerability research method comprises an implementationscheme and a research method, wherein the research method comprises a complex network theory and numerical calculation; and the complex network theory comprises a basic conception and feature parameters. According to the method, a ship route network model is established; and MATLAB software is utilized to calculate feature parameters of a complex network, wherein feature parameters comprise degree distribution, a clustering coefficient, a relative size of a maximal connected subgraph, an average efficiency of the network and a tightness index. The numerical calculation pays attention to the stability of calculation, is capable of controlling the growth momentums of errors and ensuring the stability of the calculation process, and pays attention to high calculation speed and high calculation precision, so that the numerical calculation is capable of correctly judging the property of the network and has reliability for the researches.

The invention provides an FVFD far-field integral boundary condition calculation method capable of reducing the grid usage amount. The method comprises the steps: building a simulation model, and carrying out the steady virtual time step circulation of the simulation model until the convergence is finished; in each virtual time sub-iteration process, carrying out space flux calculation and implicit iterative solution calculation on each grid block grid and each grid unit in sequence, updating a next-level virtual time sub-iteration step number conservation electromagnetic field value, and when a constant virtual time step cyclically divides an integral equation far-field condition application interval, calculating a state variable at a corresponding boundary in the region by adopting an MUSCL format interpolation, and calculating an external incoming flow state variable by adopting an equivalent current and a magnetic current calculated at an internal virtual integral surface. According to the method, a Fourier transform link required by time domain calculation of the electromagnetic characteristics of a target is reduced, and a large number of convolution calculation problems encountered in boundary condition calculation of time domain integral equations of the same type are avoided.

The invention relates to liquid crystal meter pattern visual detection methods, and provides a liquid crystal meter pattern visual detection method based on normalization Zernike moment and gray matching. The method aims to solve the problems that image error detection rate is high, flexibility is poor, and images are rotated and zoomed. The method includes the implementation steps that 1, an image to be detected and a template image are obtained; 2, a horizontal moving image to be detected and a horizontal moving template image are generated; 3, the Zernike moment of the horizontal moving image to be detected and the Zernike moment of the horizontal moving template image are calculated; 4, a scale normalization moment Znm is generated; 5, a moment vector Zsrc and a moment vector Ztem are established; 6, a determining feature vector J is established; 7, the degree of gray matching is obtained; 8, an updated determining feature vector J' is obtained; 9, the percent of similarity is obtained; 10, a detection result is obtained. The method is applied to the field of visual detection on liquid crystal meter patterns.

The invention provides a CT scanner defocusing radiation intensity distribution measurement method, and relates to the technical field of CT data correction methods. The method comprises the steps: enabling a slender cylindrical die body to be fixed in a scanning aperture, to be perpendicular to a scanning plane, and to be far away from a rotation center as much as possible; enabling an X-ray source and a detector of a scanner to continuously rotate around the rotation center of a rack and executing exposure and data acquisition; carrying out background removal on the collected data; extracting signals which are not shielded at all, calculating an empty scanning gain of each detector unit, and carrying out gain correction on all data; and for each detector unit, calculating a sampling point through which a connecting line of a defocusing surface and the detector passes, and calculating the intensity of the sampling point reaching the detector units according to the attenuation value ofthe sampling point relative to the attenuation value when the sampling point is not shielded, and thus obtaining final defocusing distribution. According to the method provided by the invention, theintensity distribution of the defocusing radiation is obtained through the actual measurement of the specific die body, and more accurate correction can be carried out for the difference of each system.

Disclosed herein is a program for calculating a displacement of a fluid comprising calculating the displacement with the fluid regarded as an elastic structural body for a given period of time.

Problem to be Solved There is provided a colony counting method capable of obtaining highly reliable and stable colony count values with easy and simple means by eliminating the variation in colony count due to image capturing conditions when the number of colonies is counted by performing data processing on an image obtained by image capturing means performing image capturing on a petri dish.

Solution When the number of colonies is counted by performing image capturing and data processing on microbial colonies developed in a culture medium 1 in a petri dish 2 by a CCD camera 7 (image capturing means) provided in an extension direction of a rotational axis C1, which is set near a center of the culture medium surface if of the petri dish, the petri dish is rotated around the rotational axis by a specified angle obtained by dividing one rotation of the petri dish by a predetermined number, and image data of the entire culture medium surface of the petri dish is acquired for each rotation by a specified angle; the number of colonies at each specified angle is counted separately by performing data processing on image data of the entire culture medium surface of the petri dish at the specified angle; and the number of colonies in the petri dish is calculated by performing numerical processing on the number of colonies counted separately at each specified angle.

The invention discloses a surface structured light three-dimensional measurement method and system based on phase weighted fusion, and the method comprises the steps: constructing a phase weighted fusion model based on different phase images obtained under multiple exposure times, calculating an accurate phase value based on the phase value under multiple exposure times, and obtaining a uniform phase distribution diagram through combining the neighborhood phase distribution. Compared with a traditional method of carrying out pixel-level replacement on a grey-scale image to realize high dynamic range image synthesis, the method has the advantages that error influence caused by factors such as camera noise and local reflection can be reduced, a more accurate phase image can be acquired, accurate matching of phase points of a left camera and a right camera is realized, and accuracy and smoothness of reconstructed point cloud are guaranteed.