The device and the method null of obtaining the approximation of the inverse number in the homogeneous coordinate which is used for the indication of image with the display

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.