| 摘要 |
An apparatus for measuring the relative differential length of a sample of a web or sheet material. The apparatus includes a substantially flat surface adapted to support the sample. Air is removed between the sample and the substantially flat surface to position the sample in an unrestrained state. A translation member translates a plurality of non-contact sensors in a first direction along the length of the sample, whereby the plurality of non-contact sensors sense the distance from a reference plane to the sample and generate a signal representative of the distance sensed. A data collection system collects the generated signals and determines a relative differential length of the sample from the generated signals.
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