| 摘要 |
1285067 Facsimile DR-ING RUDOLF HELL 26 Sept 1969 [26 Sept 1968] 47603/69 Heading H4F In a facsimile reproduction system, a triangular waveform 15 is added to the continuously varying video signal 14, and the resultant waveform is amplitude quantized to the middle of a range 10/11, 11/12, 12/13 according to the range its amplitude occurs in at samples taken at time quanta tx. The resultant quantized waveform comprises a series of pulses having durations equal to multiples of tx. By arranging that the frequency of the triangular waveform is not harmonically related to the sampling frequency 1/tx, the half-tone type dots, on a background of quantized intensity, as obtained in the reproduction, are randomly distributed and do not produce moire patterns, yet enable the reproduction of various intensities of tone. |
