| 摘要 |
A dual pointing device to be used in cooperation with an imaging apparatus, a tracking system, and an object to be imaged. The dual pointing device provides a means for tracking a point on in image in both the image's frame of reference and Euclidean absolute coordinates. This is accomplished by having two tracking systems follow the dual pointing device. Since the two tracking systems follow the same physical device, and since one tracking system operates in the image coordinates while the other tracking system operates in the absolute coordinates, the device makes it possible to effect automatic transformations between the two systems. More specifically, in the preferred embodiment of the dual pointing device, which is intended for use with a magnetic resonance imager, the absolute tracking system is based on infra-red reflectors on the device that are tracked by an infrared transponder. The image-relative tracking system is based on magnetic resonance responsive samples that are detected by the imager.
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