Patent ID: 7668689

Claim:
A velocity detection apparatus for regularly sampling a coordinate indicating a position of a moving body making a rotational motion or a reciprocating motion, and detecting an angular velocity of the moving body based on the coordinate, comprising: a memory storing a plurality of preset tentative angles and a trigonometric function value corresponding to each of the preset tentative angles; a first register storing a first actual coordinate (x 1 , y 1 ) of the moving body obtained by a first sampling; a second register storing a second actual coordinate (x 2 , y 2 ) of the moving body obtained by a second sampling next to the first sampling; a first calculator calculating a first calculational coordinate represented by an addition or a subtraction between x 1 and a value obtained as a result of shifting a figure of y 1 based on the trigonometric function value; a second calculator calculating a second calculation coordinate represented by the addition or the subtraction between y 2 and a value obtained as a result of shifting a figure of x 2 based on the trigonometric function value; and a third calculator adding up the tentative angles used in a calculation of the first or the second calculator, wherein the first and the second calculators calculate the first and the second calculational coordinates respectively so that the first actual coordinate (x 1 , y 1 ) and the second actual coordinate (x 2 , y 2 ) are closer to each other.