A technique for positioning a body having a tapered profile when viewed along a first axis comprises exposing the body to a first beam of light oriented along the first axis in a manner such that the tapered profile is projected as a first image onto a first linear array of photodectors disposed along a direction orthogonal to both the first axis and the direction of the taper. The body is exposed to a second beam of light oriented along a second axis orthogonal to the first axis in a manner such that a second profile of the body is projected as a second image onto a second linear array of photodetectors disposed along a direction parallel to the first axis. The body is then moved along the first and the second axes until the first and the second images strike predetermined locations along the first and second photodetector arrays. The location of the body is also changed along a third axis, orthogonal to the first and the second axes, until the width of the first image equals a predetermined width measured by the linear magnitude of the first image along the first photodetector array.