57 results about "Velocity function" patented technology

The invention discloses an image segmentation method for a dynamic contrast-enhanced mammary gland MRI sequence, pertaining to the field of magnetic resonance image processing techniques, which is characterized by comprising the following steps: a three-dimensional magnetic resonance image sequence of the section of the mammary gland is put into a computer; the image is divided into two parts including a mammary gland-air interface and a mammary gland-chest interface; a breast-air boundary is obtained by a splitting transaction in which a dynamic threshold controls the regional growth; an initial profile of the mammary gland and the chest is obtained in the same way, the complex profile of the breast and the chest is obtained with a method of controlling a level set; a three-dimensional magnetic resonance image sequence of a point-in-time is obtained by split jointing the segmentation results and taken as an initial position of the next group three-dimensional image segmentation. The image segmentation method of the invention increases the segmentation speed, solves the problem that a level set algorithm can not easily determine the initial profile and the velocity function and realizes an automatic segmentation of the complex dynamic contrast-enhanced mammary-gland magnetic resonance image with plenty of data.

A method of constructing a 3D geologically plausible velocity model for efficient and accurate prestack imaging wherein embodiments of the invention provide: (1) a method of calibrating velocity functions, appropriately and effectively taking into account well (hard) and seismic (soft) data as well as geological features, and trend fitting (“iDEPTHing”) RMS velocities before curved-ray prestack time migration; (2) a method of calibrating and trend fitting (“iDEPTHing”) interval velocities before prestack depth migration, appropriately and effectively taking into account well (hard) and seismic (soft) data as well as geological features; and (3) a method of constructing a geologically plausible velocity model using the previous steps of velocity calibration and trend fitting RMS and interval velocities, for efficient sequential use in prestack time migration followed by prestack depth migration. Advantages of the embodiments include providing a quick turnaround of prestack time and depth migration to interpreters and cutting back resource-intensive interpretation efforts for 3D seismic data The invention has significant implications for improving aspects of oil and gas exploration and production technologies, including pore pressure prediction, prospect evaluation and seismic attribute analysis.

The invention discloses a method for determining an optimum velocity section for pre-stack time migration in the processing of petroleum earthquake data. The method comprises the following steps of: forming a group of functions of the velocity which varies along with the reflection time of the earthquake wave for the central velocity by taking the velocity which varies along with the reflection time of earthquake wave as the central velocity and the velocity interval which varies along with the reflection time of the earthquake wave as the varying step length; performing pre-stack migration on the acquired earthquake data, wherein the result varies along with the velocity and is listed in the form of velocity spectrum; and generating the determined pre-stack time migration on a common reflection point into the optimum velocity section for the pre-stack time migration according to the strength and distribution of an energy ball on the velocity spectrum, and the optimum velocity of the re-stack time migration on a gather. By calculating the information needing to be output on a velocity analysis point in a valid velocity range, the method obviously reduces the calculation amount and improves the practicability.

Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. The methods comprise the steps of assembling seismic data into common geometry gathers in an offset-time domain without correcting the data for normal moveout. The amplitude data are then transformed from the offset-time domain to the time-slowness domain using a Radon transformation. A corrective filter is then applied to enhance the primary reflection signal content of the data and to eliminate unwanted noise events. The corrective filter has a pass region with a lower pass limit and a higher pass limit. The higher pass limit is set within 15% above the slowness of the primary reflection signals and, preferably, it is more closely set to the slowness of the primary reflection signals. The lower pass limit is also preferably set within 15% below the slowness of the primary reflection signals. The tau-P filter preferably is defined by reference to the velocity function of the primary reflection signals, and preferably is expressed as:

where r₁ and r₂ are percentages expressed as decimals. After filtering, the enhanced signal content is inverse transformed from the time-slowness domain back to the offset-time domain using an inverse Radon transformation.

Three data subsets are obtained in three selected azimuthal directions from seismic data in heterogeneous, anisotropic media. Azimuthal velocities are determined for each of the data subsets. A linear system of equations in the three selected azimuthal directions and the three determined azimuthal velocities is solved for three independent parameters. An azimuthal time migration velocity function is constructed from the three solved independent parameters. A time migration traveltime function is constructed from the constructed azimuthal time migration velocity function.

The invention relates to a method for programming a spiral curve track through die cavity numerical control machining .The boundary of a die cavity is embedded into a level set function of a high one-dimensional space; a zero level set of the level set function is the boundary of the die cavity; and the level set function is initialized to a sign distance function. Bias of the boundary of the die cavity is obtained through the solution of a level set equation; and a speed function of the level set equation is corrected so that a high-curvature region can be smooth in generating a bias line. The distance between the bias lines is controlled through the control of time for boosting the boundary; in the process of boosting the boundary of the die cavity, the complex topological change is naturally treated; and the spiral curve track is programmed in different regions respectively. The method is suitable for programming a cutter track of a numerical control machining system with a common die cavity and a complex die cavity; the cutter track is continuous and smooth; and for the complex die cavity with island, the method can realize automatic division in regions and carry out spiral curve track programming in different regions.

The invention discloses a method and a system for dividing up a three-dimensional medical image of an abdominal organ. The method comprises the following steps of: preprocessing a medical sequence image of the abdominal organ; selecting a seed point from the preprocessed medical sequence image, and using a pixel point in a preset neighborhood range of the seed point as an initial division region of the abdominal organ; acquiring an edge calculation image of the preprocessed medical sequence image according to an edge stop function, and receiving a feebleness edge drawing instruction of a user to obtain an edge image of the abdominal organ by combining the feebleness edge drawing instruction with the edge calculation image; performing level set function evolution to update a velocity function by combining a level set velocity function with the edge image; and extracting the velocity function to obtain a target region. Therefore, according to the invention, the problem of fuzzy boundary in medical image division is solved by using a user interaction type input boundary fuzzy boundary, and the quality of the three-dimensional division image of the abdominal organ is improved.

The invention provides a method for combining a near-surface velocity model with a middle-deep stratum velocity model, and belongs to the field of seismic exploration data processing. The method comprises the following steps: (1) the near-surface velocity model, an observation system, a velocity analysis reference surface and speed functions or seismic data obtained through velocity analysis are input; (2) a preferable velocity analysis reference surface of a CMP (common midpoint) is calculated according to the near-surface velocity model and the observation system; (3) velocity analysis is conducted relative to the preferable velocity analysis reference surface obtained in the steps (2) to obtain a velocity function representing the middle-deep stratum velocity model, or a speed function obtained through velocity analysis relative to a non-preferable velocity analysis reference surface is corrected according to the difference of the velocity analysis reference surface and the preferable velocity speed analysis reference surface to obtain the velocity function representing the middle-deep stratum velocity model; (4) the near-surface velocity model is combined with the middle-deep stratum velocity model.

The invention discloses a servo-motor acceleration-deceleration control method for a servo pressure machine, comprising the following steps of: constructing an acceleration function of a servo motor at an acceleration stage; establishing a speed expression of the servo motor at the acceleration stage; establishing a rotary displacement expression of the servo motor at the acceleration stage; constructing an acceleration function of the servo motor at a deceleration stage; establishing a speed expression of the servo motor at the deceleration stage; establishing a rotary displacement expression of the servo motor at the deceleration stage; and determining total acceleration time and total deceleration time. According to the servo-motor acceleration-deceleration control method, two triangular functions with different periods are adopted as acceleration-deceleration constructed functions of the servo motor, so that the change of the speed, the acceleration and the accelerated acceleration is continuous, the soft shock of the acceleration-deceleration process on the machine body is avoided, the operation stability of the pressure machine is improved and the softness of acceleration-deceleration control of the pressure machine is higher; and by full utilization of the constant and maximum output torque of the server motor under the rated rotating speed, the operation period of the servo pressure machine can be shortened and the takt time of stamping production is improved.

A device and method for calibrating linear velocity and track pitch for an optical disc is disclosed. The device comprises a frequency divider, a synchronous bit-clock generator, a counter and a linear velocity and track pitch calculator. The frequency divider receives a motor frequency generator (FG) pulse and generates a motor rotation period signal (FG/X). The synchronous bit-clock generator generates a high frequency bit-clock according to a reproduced signal read from disc. The bit counter counts the pulse of the bit-clock for each period of the motor rotation period signal to generate the data amount M. The linear velocity and track pitch calculator calculates the linear velocity by a linear velocity function with the information of the data amount M and the motor rotation period. Then, the linear velocity and track pitch calculator calculates the track pitch by a pitch function with the information of the data amount, radius and linear velocity at different tracks.

The present invention relates to the segmentation of two-dimensional gel electrophoresis images (2D images). The method according to the invention associates an initial protein seed candidate with an interface circumscribing said seed and thereafter brings said interface to evolve in accordance with a defined speed function F(x, y). The evolution of the interface is halted by a stopping criterion, C. According to the invention, the speed function can depend on a wide variety of parameters such as the pixel intensity, the curvature of the pixel intensity, the distance to the initial seed, the curvature and/or shape and/or normal direction and/or position of the evolving interface. The stopping criterion depends e.g. on the speed function F and/or the time of arrival T(x, y) and/or the departure time T_d for said interface. The invention provides criteria for a specific treatment of saturated spots and to mike sure that interfaces never overlap.

The present invention discloses a sliding method for touch control comprising the following steps. First, an input module is used to touch a first position and a second position on a touch display interface, and the touch display interface generates a time signal while being touched. The time signal is compared with a preset time signal to determine stopping actuation or sliding. In case of a sliding motion, first direction actuation is performed when a first direction function is larger than a second direction function, whereas second direction actuation is performed. Next, a velocity function signal is derived according to the distance and the time signal, and then compared with the first and second preset velocity functions to determine first, second or third velocity actuation.

The present invention relates to an acceleration control method for car following movement in the field of vehicle engineering technology. Said method includes the following steps: (1). Setting traffic condition; (2). Selecting parameter value; (3) obtaining initial state of all the vehicles; and (4). Observing running state of vehicle queue when t is greater than O. said invention is mainly aimed at preventing traffic accident.

The invention belongs to the field of resonance diffusion imaging, in particular to a fast-marching fiber tracking method based on topology preservation, comprising the steps of: reading DTI (Diffusion Tensor Imaging) data; manually selecting a seed point and initializing; evoluting from the seed point to peripheral neighbor points by using a fast-marching method and adopting a curvature weighting speed function, recording topology information in an evolution process, i.e. a source node of each evoluting point; calculating all paths by adopting a time gradient descent method; and selecting a real fiber path by a link matrix. The invention has the advantages of more according with the real fiber path by fiber tracking and reducing urious positive branches; and the obtained fiber is smooth and better reflects the fiber direction.

The invention provides a method for determining optimum velocity profile of converted-wave pre-stack time migration during seismic data processing process. The method comprises the following steps: taking converted wave velocity changing with the seismic wave reflex time as the center velocity and velocity interval changing with the seismic wave reflex time as step length, forming a group of converted wave velocity functions changing with the seismic wave reflex time based on the velocity interval; obtaining a longitudinal wave velocity function and a transversal wave velocity function by utilizing a longitudinal wave/transversal wave velocity ratio; converting the seismic data into velocity spectrum form through the converted-wave pre-stack time migration by utilizing the velocity functions respectively; determining the optimum velocity used by the converted-wave pre-stack time migration according to energy punch strength and distribution positions on the velocity spectrum, and then generating the optimum velocity profile of converted-wave pre-stack time migration. The method can perform calculation in effective velocity range, greatly reduces the calculation amount for only requiring calculating the information output on the velocity analysis points, and therefore has improved practicability.

The invention provides a burn-back energy matching control method used for a digital welding machine. The burn-back energy matching control method used for the digital welding machine mainly includesthe steps that a wire feed speed function and a welding wire diameter are obtained; a virtual wire feed speed function is determined according to the wire feed speed function and the welding wire diameter, wherein when the welding wire diameter is larger than or equal to a preset value, the function value of the virtual wire feed speed function is larger than or equal to the function value of thewire feed speed function, and when the welding wire diameter is smaller than the preset value, the function value of the virtual wire feed speed function is smaller than or equal to the function valueof the wire feed speed function; and a response is made to a welding gun switch releasing signal, the wire feed speed is controlled according to the wire feed speed function, and the welding parameter matched with the welding current is controlled according to the virtual wire feed speed function. By means of the burn-back energy matching control method used for the digital welding machine, the welding quality can be effectively improved.

The invention discloses an intravascular ultrasound image based automatic adventitia detection method. The method includes processes: transforming an intravascular ultrasound image from rectangular coordinates to polar coordinates; determining seed points needed by a Fast Marching algorithm; determining marching speed of each pixel needed by the Fast Marching algorithm according to image grayscale and gradient; automatically detecting the adventitia by the aid of the Fast Marching algorithm. The seed points, a termination point and a valid marching speed function are detected automatically, so that automaticity in the detection process is guaranteed; by the Fast Marching algorithm based processing method, simpleness and effectiveness of the detection method are guaranteed, and complexity of an existing algorithm model and dependence on imaging conditions are avoided.

A method for restarting a robot after a premature interruption of a processing program, which controls it, at an interruption point. The robot has an atomiser apparatus for automatic coating of workpieces, and the processing program is used to preset a nominal movement of the atomiser apparatus with respect to a workpiece, which is to be coated and can be moved by means of a feed device, and to preset the associated nominal atomiser parameters. After the interruption of the processing program, the atomiser apparatus is first of all moved to a restarting point, which is located on the nominal movement path and is located ahead of the interruption point. After this, the atomiser apparatus is then moved on the nominal movement path, corresponding to a predeterminable velocity function, to a transfer point which is located on the nominal movement path and is located behind the interruption point. The atomiser apparatus is switched on again between the restarting point and the transfer point. The nominal atomiser parameters which are provided by the processing program are matched and are applied at least once, between the restarting point and the transfer point, to the respective current velocity of the atomiser apparatus, in relation to the nominal velocity preset, and all of the nominal movement parameters and nominal atomiser parameters in the processing program are used when the transfer point is reached.

The invention relates to an autonomous balance riding bicycle mechanical power system and a multi-rigid-body dynamic model thereof, the mechanical power system comprises a mechanical system and an electrical control system, and the mechanical system comprises a bicycle body, a rear wheel, a front fork and a front wheel; the electric control system comprises an industrial personal computer, a direct-current power supply and an electronic gyroscope, a front fork tail adjusting device is arranged at the joint of a front fork and the vehicle body, a servo driving motor is arranged on a rear wheel,and a direction adjusting servo driving motor is arranged on the front wheel and connected with the industrial personal computer through a bus; a Kane method is adopted to establish a multi-rigid-body dynamic model of the autonomous balance riding bicycle. The method has the beneficial effects that a reliable theoretical basis is provided for the structure, parameter optimization and control system design of the autonomous balance riding bicycle; an autonomous balance running bicycle state space model is established by means of a multi-rigid-body dynamics model, and autonomous balance runningof the bicycle is achieved based on a cascade stage optimal control algorithm of a speed function.