| 摘要 |
In one aspect, the invention relates to an apparatus for monitoring thicknes s variations of an object having first and second opposing surfaces. The apparatus includes a first source positioned to project a first fringe patte rn at a first location on the first surface and a second source positioned to project a second fringe pattern at a first location on the second surface. T he apparatus further includes a first detector positioned to detect the first fringe pattern at the first location on the first surface, the first detecto r generating a first signal in response to the first fringe pattern at the fir st location. The apparatus also includes a second detector positioned to detect the second fringe pattern at the first location on the second surface, the second detector generating a second signal in response to the second fringe pattern at the first location. The apparatus further includes a processor adapted to calculate variations in the thickness of the object in response t o the first and the second signals.
|
