| 摘要 |
PURPOSE:To improve picture quality without increasing the time of transmission by varying the minimum number of bits to be transmitted according to the density of scanning lines when the minimum processing time varies with the scanning-line density. CONSTITUTION:Sensor 3 reads picture information on original 6 and inputs the information to density discriminating circuit 4 and encoding circuit 1. Circuit 4 checks black-white change points of the picture to decide the density of the picture information. Circuit 1 encodes the picture information to input a coded bit signal to counter 2 and, when one scanning line is scanned and the next scan is to be started, outputs a scanning-line encoding start signal to reset sensor 3 and counter 2, thereby driving resolution determining circuit 5. Circuit 5 increases the resolution when the output of circuit 4 is fine or decreases it when rough to drive pulse motor 7 by a required rotational frequency. The count value of counter 2 is compared 8 with the minimum number of bits determined by the mechanical restriction and according to whether the number of encoded bits is greater or less, signal ''1'' or ''0'' is outputted from circuit 8 and this is inverted and inputted to circuit 5, so that the signal showing that picture elements are fine can be substituted by a signal showing that the numbe of encoded bits is small. |
