| 摘要 |
<p>Moiré patterns in raster-scanned halftone dots image screens generated by multi-element line scanner devices are rendered imperceptible to the human eye by selecting the number of elements in the line scanner device to be that number which makes the ''once-around'' scanner frequency an integral multiple of the halftone dot screen frequency and makes the beat frequencies between the scanner and frequencies either fall outside the nominal visible spatial frequency range of about 2.5 to 250 lines per inch or fall on the screen frequency.</p> |
