Abstract: A method for position sensing includes inserting a probe having a first probe-electrode and a second probe-electrode into a body of a subject, and coupling body-surface electrodes to a surface of the body. Currents passing between the first probe-electrode and the body-surface electrodes are measured, using first circuitry coupled to at least the first probe-electrode and having a first electrical ground, and position coordinates of the probe are determined responsively to the measured currents. Second circuitry, having a second electrical ground, is coupled to at least the second probe-electrode, and the first electrical ground is isolated from the second electrical ground.

Abstract: Medical apparatus includes an invasive probe, for insertion into a body of a living subject. An ultrasonic subsystem includes an ultrasonic transducer contained in the probe and image processing circuitry, which is located outside the probe and is coupled to communicate with the ultrasonic transducer in the probe. A position sensing subsystem includes a position transducer contained in the probe and position tracking circuitry, which is located outside the probe and is coupled to communicate with the position transducer so as to determine position coordinates of the ultrasonic transducer in the body. The position sensing subsystem is electrically isolated from the ultrasonic subsystem.

Abstract: A system for position tracking includes one or more field generators, which are arranged to generate one or more respective position-varying magnetic fields. A transponder includes a resonant circuit having a resonance frequency and including a field-responsive element, which is operative to vary the resonance frequency responsively to the one or more magnetic fields. A position tracker is arranged to remotely sense the resonance frequency of the resonant circuit and to determine a position of the transponder responsively to the sensed resonance frequency.

Abstract: A method and apparatus for controlling a processing machine to perform a processing operation on a workpiece by (a) determining the nominal locations of at least two sensible reference marks on the workpiece in terms of the coordinates of the workpiece; (b) loading the workpiece on the processing machine; (c) sensing, and measuring the actual locations of, the reference marks on the workpiece when so mounted, in terms of the coordinates of the processing machine; (d) determining at least one geometrical transformation needed to transform the workpiece coordinates of the nominal locations of the reference marks to the processing machine coordinates of the actual locations of the reference marks; (e) and controlling the processing machine in accordance with the determined geometrical transformation.

Abstract: A method and apparatus for controlling a processing machine to perform a processing operation on a workpiece by (a) determining the nominal locations of at least two sensible reference marks on the workpiece in terms of the coordinates of the workpiece; (b) loading the workpiece on the processing machine; (c) sensing, and measuring the actual locations of, the reference marks on the workpiece when so mounted, in terms of the coordinates of the processing machine; (d) determining at least one geometrical transformation needed to transform the workpiece coordinates of the nominal locations of the reference marks to the processing machine coordinates of the actual locations of the reference marks; (e) and controlling the processing machine in accordance with the determined geometrical transformation.

Abstract: A method and apparatus for controlling a processing machine to perform a processing operation on a workpiece by (a) determining the nominal locations of at least two sensible reference marks on the workpiece in terms of the coordinates of the workpiece; (b) loading the workpiece on the processing machine; (c) sensing, and measuring the actual locations of, the reference marks on the workpiece when so mounted, in terms of the coordinates of the processing machine; (d) determining at least one geometrical transformation needed to transform the workpiece coordinates of the nominal locations of the reference marks to the processing machine coordinates of the actual locations of the reference marks; (e) and controlling the processing machine in accordance with the determined geometrical transformation.

Abstract: Imaging apparatus is provided which includes a generally cylindrical support defining a substrate support surface, a head operative to record information onto a substrate on the substrate support surfaces, and apparatus for precise rotational positioning and displacement of the cylindrical drum with respect to the imaging head. The apparatus includes at least one linear motor arranged to drive the cylindrical support in rotational motion, and control apparatus for providing electrical inputs to the linear motor to achieve precise rotational positioning of the substrate support surface.

Abstract: Imaging apparatus is provided which includes a generally cylindrical drum defining a substrate support surface, a head operative to record information onto a substrate on the substrate support surface, and substrate feed and position apparatus for precise rotational positioning and displacement of the substrate with respect to an internal surface of cylindrical drum. The apparatus includes a plurality of linear motors arranged along the internal surface of the cylindrical drum for feeding the substrate, and control apparatus for controlling the linear motors to achieve precise positioning of the substrate support surface.