摘要 |
<p>Lines of text (12) e.g., printing on a product (10) are verified by forming a one-dimensional image of each line substrantially parallel to its length. This one-dimensional image information is compared to corresponding information for the intended lines of text (at 30, 32). This comparison is preferably done using acousto-optic correlator systems. space and frequency multiplexing may be used to allow parallel processing of several lines of text and/or to allow comparisons with multiple references to be made simultaneously. The invention may be used to determine the acceptability of products based on the correctness of the text image, and to reject products on which the correct text does not appear (at 10R).</p> |