| 摘要 |
PURPOSE: To make the diffusion noise inconspicuous especially at low levels in a pseudocontour preventing device which renews the brightness characteristics of luminescence for each frame to conduct error diffusion. CONSTITUTION: In a device which obtains diffusion output signals and conducts pseudo half-tone display by adding reproduction errors having occurred from original pixels in the past, by combining an error diffusion circuit 11 with a luminescence brightness deviation characteristic acquiring circuit 20 which is composed of a displayed number counter 21, a displayed area rate calculating section 22, a luminescence brightness deviation characteristic measuring section 23, a brightness deviation calculating section 24 and an adder section 28, the luminescence brightness characteristic varies for every moment changing data to adapt to the gradation characteristic withoput being forcibly adjusted to the typical luminescence brightness characteristic even when the luminescence brightness characteristic varies by the data to be displayed. At the same time, since rather greater luminescence brightness level than actual is set in the adder section 28, the luminescence brightness of a rather higher value is calculated and the error is made smaller. Hence the images after error diffusion are made darker and particularly an effect to reduce diffusion noise in the low level image part is obtained, giving natural images. |
