| 摘要 |
PURPOSE:To secure the faithful reproduction for the picture in which both the line drawing and the photo coexist by deciding the types of the pictures according to the frequency distribution based on the density level of the picture element of the picture and then generating the proper output based on the decision result. CONSTITUTION:Picture signal Vi is separated through multi-value quantizer 8 into levels L1-Ln and then memorized temporarily in buffer memory 9. The contents of the separation are added via memory 9 and adder 10 and with every density level, and this result is memorized in random access memory 11. The contents of this memory shows the frequency distribution, based on which logic desicion unit 12 decides the linear pattern or the gradation pattern. And in the case of the linear pattern, controller 13 sets the threshold level of selection gate 14 to the value near Lm and sets the levels higher than Lm as the black. At the same time, the output of gradation signal generator is defined as the white. In the case of the gradation pattern, and threshold level of gate 14 is set near Ln with the levels higher than Ln is set as the black. And the gradation signal is generated from generator 15. Both the binary output of gate 14 and the gradation signal of generator 15 are supplied to operator 16 for processing and then sent to the plotter in the form of output signal Vo. |
