APPARATUS AND METHOD FOR OBTAINING APPROXIMATE VALUE OF INVERSE OF SAME ORDER COORDINATES USED FOR DISPLAY OF VIDEO ON DISPLAY DEVICE

摘要

PURPOSE: To accurately display a curved object by expressing a tertiary function as a parameter so that a curve is generated by the uniform increment of one- pixel dimension. CONSTITUTION: A W value outputted from a W adaptive forward difference unit(AFDU) circuit 10 includes 21 bits and the upper 13 bits (w0 ) out of the 21 bits are supplied to lookup tables 76, 78. The table 76 outputs the inverse (1/w0 ) of the 13 bits supplied to the table 76 to a register 80 and the table 78 similarly supplies a value (1/w0 )<2> corresponding to the upper 13 bits supplied to the table 78 to a register 82. The lower 8 bits (d) out of the 21-bit w value are supplied to an 8-bit delay register 84. Consequently, a curved object can be accurately displayed.