| 摘要 |
PROBLEM TO BE SOLVED: To enable soft wipe in small capacity wipe pattern memory by representing a wipe pattern on a polar coordinate and obtaining soft wipe pattern data by making wipe pattern data compressed and operating it. SOLUTION: A polar coordinate transforming circuit 13 coordinately transforms rectangular coordinates and outputs signals X and Y by calculating an angle dataθand distances from coordinates X, Y by an angle calculating circuit 15 and a distance calculating circuit 16 of a polar coordinate transforming circuit 14. An adding circuit 17 adds desired rotational degree information and an address offset value to the degreeθs and sends it to graphic memory 18. Distance data r is read from the memory 18, a dividing circuit 19 divides an output of the circuit 16 by the distance r, an adder 20 adds -k, a soft wipe pattern signal W is acquired through a multiplying circuit 21 and an adder 22, and a limiter 23 outputs a signal W as 1 when it is >= a level 1 among output signals of the circuit 22 and as 0 when it is <= the level 1.
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