Distance calculating method and imaging device

Abstract

The present invention relates to a distance calculation method and an image pick-up apparatus that can be favorably used in a digital camera, for example, when calculating a distance between a point corresponding to an optical axis of the lens system on an image pick-up unit and a desired point and using the calculated distance value to correct defects such as shading that occur in formed images due to peripheral light fall-off in the lens system, for example. Accordingly, in the present invention, desired coordinates from terminals 1X, 1Y and coordinates of a center position from terminals 2X, 2Y are supplied to subtractors 3X, 3Y and absolute value circuits 4X, 4Y and distance values x, y on the coordinate axes are obtained. These distance values x, y are supplied to an adder 5 and a subtractor 6, and the subtracted value is supplied to a multiplier 8 via an absolute value circuit 7 and is multiplied by a value b′ from a terminal 9. The distance value x is shifted upwards by one bit, the distance value y is subtracted by a subtractor 10, and the result is supplied to an absolute value circuit 11. The distance value y is shifted upwards by one bit, the distance value x is subtracted by a subtractor 12, and the result is supplied to an absolute value circuit 13. These absolute values are added by an adder 14 and the result is multiplied by a multiplier 15 by a value c′ from a terminal 16. The values found by the adder 5 and the multipliers 8, 15 are added by adders 17, 18 and a calculated value d′ for the pseudo distance is obtained from a terminal 19. By doing so, distances can be well calculated by a simple hardware construction.

Dependencies are inferred from the claim text.