| 摘要 |
PURPOSE:To eliminate the stripe pattern of an image caused by the non-straightness of an AD converter for subjecting a position signal to AD conversion, by a method wherein the subtraction of an analogue amount is performed prior to AD conversion and, after AD conversion, the digital amount corresponding to said analogue amount is added. CONSTITUTION:An energy signal is guided to an attenuator Z and output alphaZ is inputted to subtractors 21, 22 to be subtracted from position signals X, Y. Outputs (X-alphaZ), (Y-alphaZ) and the signal Z are inputted to AD converters 41, 42, 43 and data DigZ of the upper level bit of a digital signal DigZ is added to Dig(X-alphaZ) and Dig(Y-alphaZ) in adders 61, 62 and output is cancelled in the part of alphaZ to be brought to DigX, DigY. Because the energy signal alphaZ is generated at random, it is almost equally scattered to various parts of each step of AD conversion characteristics and, because probability generated in each code is averaged to become equal, a stripe pattern is hardly observed. |
