Position Orientation Systems, Ltd.

Ascension Technology Corporation

Selectech, Inc.

Per K Hansen

Westley S Ashe

Vladimir F Kogan

In a sourceless orientation sensor, the sensor measures the three orientation angles azimuth, elevation and roll in a fixed reference three-dimensional coordinate frame. The sensor utilizes a three-axis magnetic sensor to measure changes in the Earth's magnetic field in order to determine the azimuth and roll (or elevation) angles after the elevation (or roll) angle has been determined by other means. A first embodiment utilizes a separate sensor to measure the elevation (or roll) angle in a fixed reference three-dimensional coordinate frame while a three axis magnetic sensor is used to measure the Earth's magnetic field. The azimuth and the roll (or elevation) angles are then determined from these measurements. A second embodiment utilizes a combination of a three-axis accelerometer to sense the Earth's gravity to measure the absolute elevation and roll angles for slow motions and a two-axis rate sensor to measure the azimuth and elevation velocities in the sensor frame. A direct method employing translation and integration is used to find the azimuth and elevation angles in the fixed reference three-dimensional coordinate frame. The roll angle is then found from the magnetic sensor measurements. Other embodiments are disclosed.

Sourceless orientation sensor

A hybrid motion tracker captures the motion of a person. Magnetic field sensors and optical sources are placed on a person, each located on different limbs. A fixed transmitter emits electromagnetic energy and infrared light is transmitted from the optical light sources to the fixed optical sensors. The magnetic field sensors sense the magnetic field and a computer calculates each sensor's position and orientation relative to the fixed transmitter. The optical system's Position Sensing Detectors measure the transmitted infrared light and the computer calculates the position and orientation of each optical light source. The position and orientation of each sensor is used to reconstruct the person's motion in real time, which is sent to a host computer. The computer utilizes the optical system which is more precise than the magnetic field system to compensate for the magnetic field system and thereby achieve higher accuracies. The system is a hybrid system using both magnetic fields and infrared light. By combining the two different technologies into one system, all of the advantages of the two systems by themselves are employed and none of their disadvantages become detrimental, in particular, accuracy and dynamic performance are enhanced over results obtained through sole use of a magnetically based system.

Hybrid motion tracker

The position and orientation of remote sensors is determined using pulsed magnetic fields generated from a fixed location. Pulsed magnetic fields are sequentially generated from a plurality of spatially independent components defining a source coordinate frame. The pulsed magnetic fields are sensed by a remote sensor having a plurality of passive field sensing elements. Eddy current distortions are sensed separately and subtracted by the system. The system measures the effect of metallic objects present in the environment and dynamically adjusts the measured values accordingly. The sensed magnetic fields, free of eddy current distortion, are used in order to calculate the position and orientation of the remote object. The system shortens the duration of pulsed magnetic fields and operates correctly at much further distances for the same energy output as compared to known systems.

Magnetic field position and orientation measurement system with dynamic

The motion of a person is measured in real time using magnetic fields. A magnetic transmitter and a number of magnetic receivers are placed at different points on the person. The transmitter transmits magnetic fields sequentially from three orthogonal coils. The magnetic field is received at each receiver, which consists of three orthogonal coils. The computer resolves the sequential position and orientation coordinates from each receiver into the person's movement, relative to the transmitter, from knowledge of where each receiver is placed on the person. Other embodiments measure the transmitter's position and orientation relative to a fixed location outside of the person. The computer then resolves the position and orientation data into the person's motion relative to the fixed location outside of the person. A second embodiment uses pressure sensitive switches and accelerometers placed on the person's feet and a computer program to find the transmitter's position and orientation relative to a fixed starting location. A third embodiment uses an optical subsystem to find the transmitter's position and orientation relative to a fixed location. A fourth embodiment uses at least one further receiver placed in a fixed location outside of the person to find the transmitter's position and orientation relative to a fixed location. A fifth embodiment utilizes a special magnetic transmitter consisting of a one-axis long range transmitter and a two-axis short range transmitter and two further receivers placed at two fixed locations outside of the person to find the transmitter's position and orientation relative to a fixed location.

Magnetic motion tracker with transmitter placed on tracked object

A system for the determination of the distance and orientation of an object carrying at least three light sensors from a fixed reference point when the object is irradiated by two modulated scanning beams of known angular orientation and rotational frequency. Timing circuitry located in the control processor determines the time interval .DELTA.t, between successive interceptions of the object by each of the beams. Knowledge of this time interval and the scanning beams' relative positions and angular orientations permits calculation of the object's spatial coordinates. The optical beams utilized are fan-shaped in cross-section. The method of operation is also disclosed.

Optical 6D measurement system with two fan shaped beams rotating around

The present invention relates to an optical pointing device which preferably uses infrared light as a source and a camera as a detector. Movements of the camera with respect to the light source which remains fixed are sensed in the detector portion of the camera to determine the direction in which the camera is pointing with respect to, for example, a display screen adjacent the light source. The electronics included in the present invention are designed to act, responsive to sensing of the position of the camera with respect to the light source to cause corresponding movements of a cursor on the display screen. Other modes of operation of the present invention are also disclosed.

Optical pointing device

Disclosed herein is an omnidirectional distance measurement system which transmits and receives ultrasound waves using as many as four transmitting-receiving transducers having specially shaped beamwidths. Through the use of four such ultrasonic transducers, the system may be set up to obtain any beamwidth from 5.degree. up to 360.degree. in both the horizontal and vertical planes. In the preferred embodiment, the present invention is able to detect the distance and direction to up to four objects in a prescribed work area at any one time and may also detect the speed of any one of the objects if desired.

Omnidirectional distance measurement system

The present invention relates to a line-of-sight measuring system. The system comprises a passive optical pointing device which measures the relative change in line-of-sight of a focusing reflector attached to a target such as the operator of the device, located within a prescribed three dimensional space. The system utilizes a source of light adjacent a position sensing detector which source of light causes light to be reflected off the focusing reflector amd back to the position sensing detector. In this way, the line-of-sight between the object within the prescribed space and a particular location on a two dimensional screen positioned adjacent the prescribed space may be determined with great accuracy. The present invention also includes the electronic circuitry which interfaces the present invention with a computer such as a personal computer including an input keyboard and a display screen. Other applications of the present invention are also disclosed herein.

Line of sight measuring system

The present invention relates to an improved voice control system which is designed to be adaptable to existing computers so that the existing computers may be operated through the use of voice commands. In the preferred embodiment, the present invention is connected into the existing keyboard control means and the computer itself with the system including a priority switch controlled by software giving the keyboard priority over voice entries so that the keyboard may still be used even with the present invention connected into the circuit. In the preferred embodiment, voice commands are utilized so that the existing hardware with existing software incorporated therewith may be effectively operated in a foolproof manner. The present invention uses existing voice recognition chip technology and existing speech synthesizer chip technology in a new and unique way.

Voice control system

The present invention relates to an improved directional microphone system which utilizes at least two directional microphones. The microphones included in the system are connected to an electrical circuit which is programmed to cancel static noise and to facilitate dynamic gain control. The received signals from the two microphones are fed into a microcomputer where a fast Fourier transformation is made on the two signals in order to go from the time domain to the frequency domain. A lowpass and highpass filtering technique is used to cancel the dynamic noise. The frequency components of the incoming signals are further used to utilize an area and phase sorting technique to allow only the pickup of the wanted sound in a well-defined area. An inverse fast Fourier transformation is made and the modified signal is outputted in the time domain. Sounds generated from outside the work area are essentially cancelled out by a combination of the directionality of the microphones and the sorting techniques employed. The sorting techniques actually measure extraneous noises within the work area and compensate for them so as to enhance the signal-to-noise ratio for sounds generated within the work area. The improved directional microphone system is to be used at the table or on the floor, at a convenient distance from the user who can move freely in a well defined work area. The system eliminates the use of gooseneck and headset microphones, which are commonly used to achieve a high enough signal-to-noise ratio.

Directional microphone system

Disclosed herein are method and apparatus for position and orientation measurement using a magnetic field and retransmission thereof. In a first embodiment, three coils are deployed as a three-axis antenna. A magnetic field is transmitted sequentially from the three coils each of which coil comprises the transmitter and receiver. Three passive resonant circuits are used as retransmitters and attached to an object the position and orientation of which are to be measured. The three coils, one from each of the retransmitters, are deployed as a three-axis antenna. In a second embodiment of the present invention, the three coils mentioned above with reference to the first embodiment are deployed merely as a three-axis receiver. As such, a separate coil is provided for the purpose of transmission. The three-axis retransmitter is attached to the object, the position and orientation of which are to be determined. In a third embodiment of the present invention, a transmitter coil is provided as well as a single resonant circuit retransmitter. In conjunction with these coils, nine coils are deployed as three-axis antennas which operate as receivers to receive the retransmissions from the retransmitter which is attached to the object and the thereby enable determination of the position and orientation of the object.

Method and apparatus for position and orientation measurement using a

A system is disclosed which enables the measurement of the position and orientation of a permanent magnet within a three dimensional region in five degrees of freedom. In order to sense the position and orientation of the permanent magnet, three three-axis antennas are created with each antenna being composed of three mutually orthogonal Hall-effect devices. As is known, Hall-effect devices produce an output voltage proportional to the product of the input current, the magnet flux density and the sine of the angle between the magnet flux density and the plane of the Hall-effect device. The output voltages from the nine Hall-effect devices utilized in the system are inputted into a microprocessor device which first calculates an estimate of the position and orientation of the magnet utilizing a nonlinearized algorithm. Subsequently, the microprocessor uses a linearized algorithm to calculate the precise position and orientation of the permanent magnet. If desired, and in situations where operation is limited to a restricted area, the system may operate utilizing only six Hall-effect devices deployed as two 3-axis antennas. In one example of a system made in accordance with the present invention, operating in an area of approximately one cubic meter, the location of the permanent magnet was updated approximately 100 times per second and the location of the permanent magnet was determined with an accuracy of better than 0.5% in position and 0.5.degree. in orientation.

Magnetic position and orientation measurement system

Disclosed are two embodiments of displacement sensing devices utilizing adjustable tuned circuits. In a first embodiment, a sensor comprising a capacitor and an adjustable coil connected together is attached to two relatively movable objects; the relative displacement of which is to be measured. An electrical circuit is provided which includes an oscillator which may be swept through a predetermined range of frequencies so as to variably excite a source coil. As the oscillator is swept through these frequencies, a comparator compares the voltage output of the oscillator with the voltage output of the source coil. When the frequency of the oscillator is equal to the resonant frequency of the sensor circuit at its particular coil displacement, a voltage drop across the source coil will be sensed by the electrical circuitry and from this information, the circuitry may calculate the actual displacement of the two objects with respect to one another. In a second embodiment of the present invention, the same sensor is used and the electrical circuitry includes an oscillator which places a voltage across a source coil while the oscillator frequency is swept between two predetermined extremes. A separate detector coil is provided in the electrical circuitry and this detector coil senses phase changes caused by the effect of the source coil frquency upon the sensor circuitry. A phase-to-voltage converter converts the phase of the detector coil to a voltage which is indicative of the displacement of the objects with respect to one another.

Displacement sensing device utilizing adjustable tuned circuit

A device is disclosed which enables calculation of the location of an object within a three dimensional work area. The system utilizes a pair of position sensing detectors each of which is surrounded by light emitting diodes (LED's) and requires attachment of a retro-reflector to each target whose position is to be determined. In a preferred embodiment, each position sensing detector is surrounded by infrared LED's of two different light wavelengths. Two targets are present in the work area each with a retro-reflector attached thereto and each including a single bandpass filter, in front of its retro-reflector, one target having a bandpass filter corresponding to one LED wavelength and the other target having a bandpass filter corresponding to the other LED wavelength. Circuitry is also disclosed which drives the LED's and interprets the signals received by the position sensing detectors so that the position of the two targets may be determined and displayed in the form of x, y, and z coordinates.

Passive optical position measurement system

A system measures the (x, y) coordinates of a target, for example, a pointed finger on a flat surface such as a rectangular plate. A pair of ultrasonic transducers are placed on the plate so that one transducer is located at each of the two left corners of the plate or at each of the two top corners of the plate. The transducers transmit short ultrasonic pulses which are reflected as echos off the target and then received by the transducers. The time elapsed between the transmitting of each pulse and receiving its echo is converted into distances between the transducers and the target, which distances are then converted into the target's (x, y) coordinates. The system is designed to clamp onto a number of flat surfaces, thereby allowing the system to be used with printed representations of keyboards, graphs, CRT monitors and standard television screens. The system is interfaced with any of a variety of computers and provides a signal representative of the location of the target to the computer. The system is also designed so that it can be placed inside any new or existing frame around the flat surface.

Growing community of inventors

Burlington, VT, United States of America

Per K Hansen