1170 results about "Quaternion" patented technology

An inertial sensor based surgical navigation system for knee replacement surgery is disclosed. Inertial sensors composed of six-degree-of-freedom inertial chips, whose measurements are processed through a series of integration, quaternion, and kalman filter algorithms, are used to track the position and orientation of bones and surgical instruments. The system registers anatomically significant geometry, calculates joint centers and the mechanical axis of the knee, develops a visualization of the lower extremity that moves in real time, assists in the intra-operative planning of surgical cuts, determines the optimal cutting planes for cut guides and the optimal prosthesis position and orientation, and finally navigates the cut guides and the prosthesis to their optimal positions and orientations using a graphical user interface.

Described herein are systems and methods for performing multi-stage detection and classification of cancer regions from digitized images of biopsy slides. Novel methods for processing the digitized images to improve feature extraction and structure identification are disclosed, including but not limited to the use of quaternions, logarithmic mappings of color channels, and application of wavelets to logarithmic color channel mappings. The extracted features are utilized in improved machine learning algorithms that are further optimized to analyze multiple color channels in multiple dimensions. The improved machine learning algorithms include techniques for accelerating the training of the algorithms, making their application to biopsy detection and classification practical for the first time. The performance of the described systems and methods are further improved by the disclosure of a novel multistage machine learning scheme, in which additional classifiers are utilized to choose among the classes proposed by other classifiers in close cases.

Higher Order Sliding Mode (HOSM) control techniques are applied to the Guidance Control (G&C) of interceptor missile in which velocity may be steered by combination of main thrust, aerodynamic lift and lateral on-off divert thrusters, and attitude may be steered by continuous or on-off actuators. Methods include the pointing of the seeker, its associated estimation processes, a guidance law that uses concurrent divert mechanisms, and an attitude autopilot. The insensitivity of the controller to matched disturbances allows the concurrent usage of the divert mechanisms without adverse effect on the accuracy. The controller also allows the de-coupling of the control of roll, pitch and yaw channels, and usage quaternions to represent body attitude and it provides control perfect robustness. While it conceivable to design separately the components of the G&C method, it is widely accepted that designing them in an integrated fashion usually produces a better result.

Novel techniques for estimating compass and gyroscope biases for handheld devices are disclosed. The handheld devices can include wireless phones, navigational devices and video gaming systems. The compass bias can be determined by causing a small movement of the handheld device and comparing the data obtained from the compass with the data obtained from the gyroscope. The gyroscope bias can be determined by obtaining a quaternion based angular velocity term of the handheld device when the accelerometer and compass data are reliable, and then comparing the angular velocity term to with the gyro data estimate the gyro bias. When the compass and/or the accelerometer data are unreliable, a previously determined quaternion angular velocity term is used, which was determined when the compass and the accelerometer were providing reliable data. The gyroscope bias can also be determined by measuring gyroscope biases at various temperatures in a non-factory setting, and storing that data in a memory, and using the data to estimate gyro biases when the accelerometer and/or the compass data are unreliable.

The invention discloses a human body movement reconstruction and analysis system and method based on inertial sensing units. The system comprises a pose information acquisition system, a WIFI wireless router and a central computer. The pose information acquisition system is composed of the inertial sensing units. The inertial sensing units are installed on multiple parts of a human body respectively to collect accelerated velocities, angular velocities and magnetic information of all the parts in real time and fuse the accelerated velocities, the angular velocities and the magnetic information to obtain pose information such as pose angles, quaternions and Euler angles; next, the collected information and the fused information are sent to the central computer through the WIFI wireless router in a WIFI mode; the central computer fuses pose information data of all the inertial sensing units to complete human body movement reconstruction and extracts movement parameters such as positions, velocities, angles, the accelerated velocities and angular accelerated velocities, and the movement parameters are used for biomechanical analysis and kinematic analysis of human body movement. By means of the human body movement reconstruction and analysis system and method, influences on the movement of a subject are reduced to the maximum extent, the requirements for capturing the movement of the whole body of the subject and the special movement of a specific part of the subject are both met, and the system and method are suitable for various application occasions.

The invention relates to a system capable of realizing immersive virtual reality across mobile platforms. A DirectX3D rendering technology is adopted to perform distortion correction and distortion scale on images rendered by virtual three-dimensional scenes via a Pixel Shader, the images are segmented and drawn on left-eye and right-eye screens of HMD equipment, and a refresh frequency of more than 60 frames per second is kept; position information and facing information of the HMD equipment are acquired from a sensor and used for head tracking, and coordinate and rotating quaternion information are fed back to an application program via a message interface; and interaction between a client end and a server end is realized by adopting a wireless communication technology. The system provided by the invention has the advantages that one product only needs to be developed for once, reality is enhanced, virtual objects not existing in the real environment are generated via a computer graphic technology and a visualization technology, the virtual objects are accurately 'placed' in the real environment via the sensing technology and are integrally mixed with the real environment by the aid of displaying equipment.

A method and system senses the attitude of an accelerating object by measuring acceleration with accelerometers in three orthogonal axes and measuring angular rate with angular rate sensors disposed about each such axis to compute attitude of the object accurately relative to a vertical axis. A processor updates a quaternion representation of attitude based upon the angular rate of the object, and a corrective rate signal is determined from level frame acceleration as a reference for a Kalman filter in calculating the attitude of the object. When velocity or airspeed is available from an external source, an aiding algorithm is employed to provide accurate attitude representations throughout all flight regimes.

This invention provides a system and method for determining position of a viewed object in three dimensions by employing 2D machine vision processes on each of a plurality of planar faces of the object, and thereby refining the location of the object. First a rough pose estimate of the object is derived. This rough pose estimate can be based upon predetermined pose data, or can be derived by acquiring a plurality of planar face poses of the object (using, for example multiple cameras) and correlating the corners of the trained image pattern, which have known coordinates relative to the origin, to the acquired patterns. Once the rough pose is achieved, this is refined by defining the pose as a quaternion (a, b, c and d) for rotation and a three variables (x, y, z) for translation and employing an iterative weighted, least squares error calculation to minimize the error between the edgelets of trained model image and the acquired runtime edgelets. The overall, refined/optimized pose estimate incorporates data from each of the cameras' acquired images. Thereby, the estimate minimizes the total error between the edgelets of each camera's/view's trained model image and the associated camera's/view's acquired runtime edgelets. A final transformation of trained features relative to the runtime features is derived from the iterative error computation.

The invention discloses flywheel based attitude maneuvering control device and method for successive approaching of a satellite rounding an instantaneous Euler shaft and relates to control device and method for satellite attitude adjustment. The invention is provided for solving the problems of great fuel consumption, short service life of a satellite, complex configuration of an air injecting control system and difficult reduction of size and weight of the satellite existing in the realization of satellite wide-angle attitude maneuvering by adopting air injecting control. The method comprises the following steps of: setting a parameter of the control device according to the system requirement of the control device and obtaining attitude deviation angular velocity according to a motion equation; and expressing a relationship of the instantaneous Euler shaft and a deviation angle of the current attitude and a target attitude of the satellite by an attitude error quaternion to obtain a control signal, calculating to obtain a flywheel control input moment vector calculated by a satellite controller, to be used as a data control command as a basis for generating moment by a back action flywheel. The invention does not consume other resources on the satellite or consume fuel, prolongs the service life of the satellite and can be widely suitable for various satellites needing attitude maneuvering.

A non-linear alignment method of a strapdown inertial navigation system comprises the following steps of: acquiring data of an accelerometer and a fiber gyroscope of the fiber strapdown inertial navigation system and carrying out denoise processing, realizing coarse alignment and fine alignment processes by the utilization of an analysis method and a compass method, establishing a quaternion-based strapdown inertial navigation system non-linear error model under the condition that attitude angle and azimuth angle are both large misalignment angles, establishing an observation model with speed as observed quantity, carrying out iterative and filter estimation by the use of an improved UKF algorithm on the basis of the model so as to obtain the misaligned angle of the platform, continuously carrying out closed-loop feedback and correcting attitude matrix of the strapdown inertia system in the previous period, so as to accurately complete the initial alignment process. The method can be used to guarantee safety and confidentiality of the initial alignment without the utilization of other sensor information. By the introduction of the quaternion error based non-linear system error model, linearization is not required to guarantee the precision of the model. Computational complexity is reduced, and filtering is carried out on the established non-linear system so as to complete fine alignment.

The invention relates to a spacecraft fault tolerance attitude cooperation tracking control method based on a normalized neural network, and belongs to the technical field of spacecraft formation flight. According to the method, an attitude motion model of a single spacecraft is built, errors are defined, a control law is designed for the model, a sliding mode function is designed, the derivative of the sliding mode function is solved, an error model is obtained, a control law based on an input normalized neural network is designed, and the states of the spacecrafts are cooperative and consistent; each spacecraft calculates the required control torque according to attitude information of itself and the adjacent spacecraft, the calculated control torque is acted on the corresponding spacecraft via an execution mechanism of each spacecraft, the angular velocity is solved via an obtained attitude dynamic equation, a unit quaternion attitude tracks an expected attitude via the attitude dynamic equation, and consistent attitude of the spacecraft formation is finally realized. According to the method, estimation errors of non-linear function approximation are reduced, the calculating time is reduced, and the convergence rate and the control precision of the system are increased.

The invention discloses a decoupling control method for relative orbits and attitudes of formation satellites, relates to the technical field of the control of the orbits and attitudes of a spacecraft formation, and solves the problems of large satellite calculation amount and low orbit solving efficiency caused by high control dimension of the formation satellites due to serious coupling of the relative orbits and the attitudes of the formation satellites. The method gives two decoupling conditions at first, so that the control of the relative orbits and the attitudes can be designed independently; a thrust vector mobility decoupling constraint condition is introduced to the initialization control of the relative orbits according to satellite attitude mobility constraints indirectly; and during the optimal thrust vector attitude tracking, the possible orientation in space, which meets solar avoidance constraints, of a star sensor optical axis (1) is sought by using a geometric method, and the optimal attitude quaternion and attitude angular velocity are calculated finally by using a double-vector attitude determination algorithm. The method provides important reference value for the control of the orbits and the attitudes of the spacecraft formation.

A method and system senses the attitude of an accelerating object by measuring acceleration with accelerometers in three orthogonal axes and measuring angular rate with angular rate sensors disposed about each such axis to compute attitude of the object accurately relative to a vertical axis. A processor updates a quaternion representation of attitude based upon the angular rate of the object, and a corrective rate signal is determined from level frame acceleration as a reference for a Kalman filter in calculating the attitude of the object.

The invention provides a correction method for on-track aberration of a star sensor. The method comprises the following steps of: calculating the annual aberration constant of a satellite according to a formula; measuring the linear velocity of the satellite in an inertial coordinate system by using a satellite borne device; calculating the altitude of the satellite in the inertial coordinate system; calculating the optical axis direction of the star sensor in the inertial coordinate system; calculating the linear velocity vertical to the optical axis direction of the star sensor in the inertial coordinate system; calculating the diurnal aberration constant vertical to the optical axis direction of the star sensor; calculating the included angle between a fixed star direction and the optical axis direction in the view filed of the star sensor; calculating aberration synthesis caused by all factors; and calculating an altitude quaternion. In the invention, a mathematical model for eliminating the diurnal aberration and annual aberration of the star sensor and the peculiar motion aberration of the sun is induced; after the model is used to eliminate aberration, altitude information with high accuracy can be further provided for an aircraft, the angular speed of a non-gyro aircraft can be calculated by using altitude, and the accuracy of angular speed calculation can be further improved.

The invention relates to the technical field of unmanned aerial vehicles and discloses a pan-tilt attitude detection method and a pan-tilt attitude detection device. The method comprises the following steps: acquiring data of a pan-tilt inertia measurement unit, wherein the data of the inertia measurement unit includes angular velocity data of a gyro and accelerometer data; performing quaternion integral operation on the data of the inertia measurement unit; changing the data of the inertia measurement unit from quaternion expression into rotation matrix expression; and changing the data of the inertia measurement unit from the rotation matrix expression into eulerian angle expression, wherein the step of performing the quaternion integral operation on the data of the inertia measurement unit comprises the following sub-steps: by taking the rotation matrix expression as feedback, performing feedback correction on the quaternion expression, acquiring pan-tilt attitude data through an attitude heading system, performing pan-tilt attitude expression by adopting different algorithms and compensating and correcting the pan-tilt attitude. Therefore, the accuracy of the pan-tilt attitude detection is improved.

The invention discloses a real-time navigation system and a real-time navigation method for an underwater structure detection robot. The navigation system comprises a magnetic compass, a gyroscope, an accelerometer, a depth meter and a navigation microprocessor, wherein the magnetic compass, the gyroscope, the accelerometer and the depth meter are used for respectively collecting magnetic field intensity, an angular speed, a linear speed and submerged depth data and transmitting the magnetic field intensity, the angular speed, the linear speed and the submerged depth data to the navigation microprocessor; the navigation microprocessor is used for calculating attitude and position of the underwater robot according to the collected data. The navigation method comprises an attitude algorithm, a speed algorithm and a depth algorithm; according to the attitude algorithm, a complementary filtering method, a quaternion gradient descent method and a Kalman algorithm are combined for obtaining an attitude matrix and an attitude angle; the speed algorithm is used for calculating the speed and the position of the robot by using a three-order upwind scheme with rotary compensation; the depth algorithm is used for processing the data of the depth meter by using a moving average filter algorithm so as to obtain the submerged depth. By virtue of the real-time navigation system for the underwater structure detection robot and the method thereof, the navigation cost is reduced and a relatively good navigation precision is achieved.

The invention discloses a method for determining the attitude of a flight carrier, which belongs to the field of attitude measurement. The main steps include: establish the coordinate system and attitude matrix of the flight carrier; collect sensor signals; use the gyro measurements to carry out strapdown attitude calculations to obtain the attitude quaternions and attitude angles of the flight carrier; use the magnetometer measurements to calculate the flight Carrier heading angle; use speed information to compensate acceleration measurement value, solve pitch angle and roll angle; solve attitude quaternion determined by magnetometer and accelerometer information; design Kalman filter, estimate state vector; correct attitude four arity and extract attitude angle. This method combines gyroscopes, accelerometers, magnetometers, and speed sensors to meet the requirements of real-time attitude control of the flight carrier; introduces gyroscope drift into the system state vector, estimates and corrects it in real time, and uses the measured value of the magnetometer to directly Calculate the heading angle, avoid the calculation of the geomagnetic field vector in the geographic coordinate system, and improve the accuracy of attitude determination.

The invention belongs to the field of computer vision and particularly relates to a quaternion time-space convolutional neural network-based human body behavior identification method. The method comprises the following specific implementation steps of (1) inputting a to-be-identified action video set; (2) performing image preprocessing, and extracting a key region image of a human body motion; (3) constructing a quaternion time-space convolutional neural network; (4) training the network by adopting a BP algorithm, and outputting a training result; and (5) inputting a video test set, and outputting a test result. According to the method, the region image of the human body motion is extracted by utilizing a codebook model, so that the human body motion can be detected under the condition of a complex background; and the quaternion time-space convolutional neural network directly takes a color image as an input, so that the problem of image feature deficiency in a process of converting the color image into a grayscale image or performing processing by channels in a conventional convolutional neural network is solved, the performance of network feature extraction is improved, and the human body behavior identification is more accurate.

A spacecraft attitude fixing method of DD2 (Divided Difierence 2) filter and a counting method based on Euler-q (Euler-quaternion) are provided, which relates to a state estimation and attitude determination method based on vector observation. The invention is characterized in that: according to the reference ephemeris and the reference vector and the observation vector observed by a star sensor, the spacecraft attitude quaternion can be gotten through Euler-q counting method; through DD2 filter, on one hand, feedback compensation the attitude matrix obtained through resolving by gyro; on the other hand, revise the palstance output of three-axle gyro and conduct compensation to the constant drift of gyroscope. As for that, the current spacecraft attitude information when getting high precision can be achieved, the constant drift of gyroscope can be scaled on line. The invention is an unattended attitude determining method, which is characterized in high precision and good timeliness, being convenient and feasible, and can be used in the attitude fixing system of various spacecrafts.