Measurement element position determination

Abstract

An apparatus for determining measurement element positions, comprising a plurality of measurement elements; at least one trigger element corresponding to each element of the plurality of measurement elements; a positional encoder configured to register a position of each of the measurement elements when the trigger element is activated; and a controller, wherein the controller constructs a surface geometry model from the registered measurement element positions.

Description

RELATED APPLICATIONS [0001] The present application is a continuation-in-part of PCT Application No. PCT / IL2004 / 000069, filed on Jan. 23, 2004, and a continuation-in-part of PCT / IL2004 / 000062, filed on Jan. 22, 2004, which is a continuation-in-part of U.S. application Ser. No. 10 / 350,288, filed Jan. 23, 2003, the disclosures of all of which are incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention relates to the determination of measurement element positions, for example for the measurement of surface geometries. BACKGROUND OF THE INVENTION [0003] There are many applications where knowing the surface structure or internal structure of an object is desirable. A typical solution for ascertaining hard tissue surface structure, especially if the tissue is hard and is underlying soft tissue as is the case in dental care, is to obtain X-Ray CT images of the hard tissue to construct a model based on the images. [0004] Another methodology for determining the s...

AI Technical Summary

Benefits of technology

[0005] An aspect of some embodiments of the invention relates to determining the surface structure or internal structure of an object. The object could be organic, such as a mandible, knee or spinal cord, or inorganic. Various measurement elements can be utilized, either penetrating or non-penetrating depending on the surface to be measured, in conjunction with at least one position encoder to collect position data points which when viewed in conjunction portray the surface being measured. Optionally, a single position encoder is used to accurately measure the position of a plurality of parallel measurement elements, obviating the need for multiple encoder measurement of multiple individual measurement elements. Sensory devices are used to signal measurement element contact with the object. Optionally, the sensory devices act as a mechanical and electrical fuse.

[0006] An aspect of some embodiments of the invention relates to accurately measuring the position of a measurement element, such as a needle or pin, only when the element contacts hard tissue, such as bone. Optionally, the invention relates to accurately measuring the position of a measurement element, wherein the measurement element is designed to penetrate one material type and not another. Analysis of these positions allows for a model of the surface geometry measured to be created.

[0008] An aspect of some embodiments of the invention relates to determining the structure of a knee joint, optionally including cartilage tissue. Measurement elements are used which are optionally designed to penetrate one tissue type but not another. In some embodiments, measurement elements are used which are non-penetrating. Optionally, non-penetrating and penetrating measurement elements are used in combination. Measurement elements are advanced until they make contact with the material they were designed not to penetrate. Individual position measurements of the measurement elements are made once a controller is signaled by a sensory device. Optionally, the sensory devices act as a mechanical fuse to prevent the measurement elements from exerting undesired pressure on a target area. Analysis of these positions allows for a model of the surface geometry measured to be created.

[0014] An aspect of some embodiments of the invention relates to three dimensional scanning using a plurality of sensory devices, or triggers, in lieu of positional encoders. Instead of reading the advancement of the element providing motive force, such as a piston or screw, a series of spaced triggers can be located along the path of motion of a printed circuit board (or microelectromechanical system device or some other substrate) being used to advance measurement elements. As the printed circuit board moves forward, it trips the triggers one by one. Analysis of the number of triggers tripped allows for the measurement of the penetration of the measurement elements.

Problems solved by technology

The multiple position determination may cause registration and / or other accuracy problems.

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