Abstract: A control device in one embodiment includes a first transmission unit, a first receiving unit, and a first generation unit. The first transmission unit is configured to transmit first performance data including contents of playing a keyboard instrument at a first communication base to a second communication base. The first receiving unit is configured to receive second performance data from the second communication base. The first generation unit is configured to generate a drive signal to produce a sound in accordance with the second performance data and output the drive signal to a sound generation device at the first communication base. At least one of the first performance data and the second performance data includes a key position signal indicating a key press amount on the keyboard instrument.

Abstract: In a geomagnetism measurement apparatus, a magnetic sensor detects magnetic data, and a storage unit stores the magnetic data sequentially output from the magnetic sensor. An ellipsoid generation unit calculates each ellipsoidal central point of first, second and third ellipsoids each of which has in the vicinity thereof a plurality of the magnetic data stored in the storage unit. An ellipsoidal central point decision unit decides whether or not a distance between respective ellipsoidal central points is equal to or less than a threshold value. A correction value generation unit calculates an ellipsoidal correction matrix for converting coordinates on an ellipsoid into coordinates on a sphere based on a coefficient matrix representing a shape of one of the first, second and third ellipsoids according to the decision result.

Abstract: A geomagnetic field measurement device has a three-dimensional magnetic sensor and a storage device that stores plural pieces of magnetic data sequentially output from the three-dimensional magnetic sensor. The geomagnetic field measurement device calculates, based on the pieces of magnetic data, a distortion estimation value indicating a degree of difference in shape between a three-dimensional figure defined so that the plural sets of coordinates indicated respectively by the plural pieces of magnetic data are distributed adjacent to a surface thereof and a spherical surface, and determines whether there is distortion in the shape of the three-dimensional figure based on the distortion estimation value, to update an offset for correcting each of the plural pieces of the magnetic data in a case in which it is determined that there is no distortion.

Abstract: In a magnetic data processing device, a magnetic data input part sequentially receives magnetic data output from a three-dimensional (3D) magnetic sensor. A storage part stores a plurality of the magnetic data as a data set of statistical population. An acceleration data input part receives acceleration data output from a 3D acceleration sensor. A reliability determination part derives a reliability index that is a function of an angular difference between a direction of a line perpendicular to an approximate plane representing a distribution of the data set of the statistical population and a direction of acceleration represented by the acceleration data.

Abstract: An offset estimation method calculates attitude data representing an attitude variation of equipment from a reference attitude thereof based on angular velocity data that is outputted from an angular velocity sensor and that represents angular velocity of the equipment. The offset estimation method further calculates an estimation value of the offset minimizing an error between first variable vectors associated to the attitude data and second variable vectors associated to magnetic data that are successively outputted from a magnetic sensor. The first variable vector is obtained by changing a reference variable vector in accordance with the attitude variation represented by the attitude data, the reference variable vector representing geomagnetism when the equipment is placed in the reference attitude, and the second variable vector is obtained by subtracting the estimation value of the offset from the magnetic data.

Abstract: From a first estimation value of attitude of equipment at a first time, a second estimation value of attitude of the equipment at a second time is derived. For this purpose, a predicted value of the attitude at the second time is generated by applying the first estimation value to a state transition model indicating transition of attitude of the equipment. Then, a difference between the predicted value of the attitude and a true value of the attitude of the equipment is calculated based on data outputted from a sensor in the equipment to thereby generate an estimated attitude error between the predicted attitude and true attitude of the equipment. Further, a specific attitude component is extracted from a plurality of attitude components of the estimated attitude error. Lastly, the second estimation value is calculated based on the predicted value of the attitude and the specific attitude component.

Abstract: A display device has a screen that can be positioned in arbitrary postures including a reference posture relative to a space having a reference horizontal orientation. The screen has an xyz orthogonal coordinate system, and the posture of the screen in the space is defined by z-x-z Euler angles ?, ?, and ? of the xyz orthogonal coordinate system. The screen displays an image to enable recognition of the reference horizontal orientation of the space. A control device derives a specific parameter ?+? as an angle by which the image is rotated so that the reference horizontal orientation recognized from the image follows the reference horizontal orientation of the space when the image is displayed on the screen at arbitrary postures.

Abstract: In a magnetic data processing device, an input part sequentially receives magnetic data output from a magnetic sensor. A storage part stores a plurality of the magnetic data as a data set of statistical population. An index derivation part derives a distribution index of the data set of the statistical population. A reliability determination part determines whether or not reliability of the data set of the statistical population is acceptable based on the distribution index and a decision criterion. A decision criterion setting part increases strictness of the decision criterion when the reliability determination part determines that the reliability of the data set of the statistical population is acceptable, and decreases the strictness of the decision criterion when the reliability determination part determines that the reliability of the data set of the statistical population is unacceptable.

Abstract: A state estimation apparatus has a plurality of sensors including a three-dimensional magnetic sensor for detecting magnetic components. A Kalman filter is used to update a state vector based on an observation residual. The state vector has components representing a plurality of state variables which include a state variable for estimating an offset of the magnetic data. A central point calculation unit assumes that coordinates indicated by a predetermined number of the magnetic data probabilistically distribute in the vicinity of a spherical surface, and calculates a central point of the spherical surface. The Kalman filter updates the state variable for estimating an offset of the magnetic data using the central point of the spherical surface.

Abstract: In a geomagnetism measurement apparatus, a magnetic sensor detects magnetic data, and a storage unit stores the magnetic data sequentially output from the magnetic sensor. An ellipsoid generation unit calculates each ellipsoidal central point of first, second and third ellipsoids each of which has in the vicinity thereof a plurality of the magnetic data stored in the storage unit. An ellipsoidal central point decision unit decides whether or not a distance between respective ellipsoidal central points is equal to or less than a threshold value. A correction value generation unit calculates an ellipsoidal correction matrix for converting coordinates on an ellipsoid into coordinates on a sphere based on a coefficient matrix representing a shape of one of the first, second and third ellipsoids according to the decision result.

Abstract: A geomagnetic field measurement device has a three-dimensional magnetic sensor and a storage device that stores plural pieces of magnetic data sequentially output from the three-dimensional magnetic sensor. The geomagnetic field measurement device calculates, based on the pieces of magnetic data, a distortion estimation value indicating a degree of difference in shape between a three-dimensional figure defined so that the plural sets of coordinates indicated respectively by the plural pieces of magnetic data are distributed adjacent to a surface thereof and a spherical surface, and determines whether there is distortion in the shape of the three-dimensional figure based on the distortion estimation value, to update an offset for correcting each of the plural pieces of the magnetic data in a case in which it is determined that there is no distortion.

Abstract: A magnetic data processing device sequentially receives magnetic data samples each of which is three-dimensional vector data represented by a linear combination of fundamental vectors and which are outputted from a three-dimensional magnetic sensor. The magnetic data processing device defines a statistical population which includes a plurality of the magnetic data samples sequentially inputted and which signifies a rotation of the three-dimensional magnetic sensor of a predetermined range, and operates when a distribution of the magnetic data samples of the statistical population is flat, for deducing a direction perpendicular to a plane which approximates the flat distribution of the statistical population, as vertical-direction data representing a vertical direction.

Abstract: In a magnetic data processing device, an input part sequentially receives magnetic data qi output from a magnetic sensor. A storage part sequentially stores the magnetic data received through the input part. An offset derivation part derives an offset according to a probabilistic method using a plurality of the magnetic data stored in the storage part as a statistical population. The offset derivation part assumes that an error ?pi contained in each of the magnetic data qi is a random variable vi following a probability distribution ?, and uses an expected value corresponding to the probability distribution ? for deriving the offset. Specifically, the offset derivation part calculates an index representing variance of distances from the offset to respective ones of true magnetic data that are obtained by subtracting each ?pi from each magnetic data qi of the statistical population, and derives the offset which minimizes the expected value of the calculated index.

Abstract: In a magnetic data processing device, an accumulating part repeatedly accumulates a predetermined number of magnetic data q1, . . . , qN (N?4) to provide a statistical population, the predetermined number being four or greater, while sequentially acquiring magnetic data output from a three-dimensional (3D) magnetic sensor. A determination part derives, each time a statistical population is provided, a minimum value of f(p) as a reliability index S of the statistical population, and determines whether or not the statistical population is sufficiently reliable using the reliability index S.

Abstract: In a magnetic data processing device, an accumulation part repeatedly accumulates a predetermined number of magnetic data to provide a statistical population, while sequentially acquiring magnetic data output from a 3D magnetic sensor. A determination part determines, when the predetermined number of magnetic data is accumulated as a statistical population, whether or not the statistical population is spread two-dimensionally using a first threshold, and determines, when the statistical population is spread two-dimensionally, whether or not an angle between a first plane and a second plane is small to a negligible extent using a second threshold, the first plane including a circle about which the statistical population is concentrated, and the second plane being perpendicular to a line segment connecting a center of the circle and a current offset of the magnetic data.

Abstract: In a magnetic data processing device, an accumulating part sequentially acquires magnetic data output from a 3D magnetic sensor to provide a recent statistical population of the magnetic data. A past statistical population storage part stores, as a past statistical population, magnetic data output from the 3D magnetic sensor prior to the magnetic data accumulated as the recent statistical population. A determination part determines whether a distribution of the recent statistical population satisfies a certain condition, and determines whether a mixed statistical population of the past and recent statistical populations satisfies another condition when the recent statistical population does not satisfy the certain condition. An offset derivation part derives an offset of the magnetic data based on the recent statistical population when it satisfies the certain condition and derives an offset of the magnetic data based on the mixed statistical population when it satisfies said another condition.

Abstract: A magnetic sensor control device has an input section, a selection section, a calculation section, and a setting section. The input section inputs a plurality of magnetic data each having 3 components sequentially output from a 3-dimensional (3D) magnetic sensor. The selection section selects 4 magnetic data satisfying a predetermined 4-point selection condition from the plurality of the input magnetic data. The calculation section calculates a center point equally distant from 4 points corresponding to the 4 selected magnetic data. The setting section sets 3 components representing the center point as an offset of the magnetic data.

Abstract: A display device has a screen that can be positioned in arbitrary postures including a reference posture relative to a space having a reference horizontal orientation. The screen has an xyz orthogonal coordinate system, and the posture of the screen in the space is defined by z-x-z Euler angles ?, ?, and ? of the xyz orthogonal coordinate system. The screen displays an image to enable recognition of the reference horizontal orientation of the space. A control device derives a specific parameter ?+? as an angle by which the image is rotated so that the reference horizontal orientation recognized from the image follows the reference horizontal orientation of the space when the image is displayed on the screen at arbitrary postures.

Abstract: In a magnetic data processing device, an input part sequentially receives magnetic data output from a magnetic sensor. A storage part stores a plurality of the magnetic data as a data set of statistical population. An index derivation part derives a distribution index of the data set of the statistical population. A reliability determination part determines whether or not reliability of the data set of the statistical population is acceptable based on the distribution index and a decision criterion. A decision criterion setting part increases strictness of the decision criterion when the reliability determination part determines that the reliability of the data set of the statistical population is acceptable, and decreases the strictness of the decision criterion when the reliability determination part determines that the reliability of the data set of the statistical population is unacceptable.

Abstract: In a magnetic data processing device, an input part sequentially inputs magnetic data outputted from a two-dimensional or three-dimensional magnetic sensor. The magnetic data is two-dimensional or three-dimensional vector data that is a linear combination of a set of fundamental vectors. The magnetic data processing device stores a plurality of the inputted magnetic data as a data set of statistical population in order to update an old offset of the magnetic data with a new offset. An offset derivation part derives the new offset based on the old offset and the data set of statistical population under a constraint condition that the new offset be obtained as the sum of the old offset and a correction vector.