主权项 |
1. A vibration correction control circuit for correcting an optical axis of an image pickup apparatus in response to a vibration thereof, the circuit comprising:
a vibration-component signal generating unit configured to generate a vibration-component signal indicating an amount of movement of an image pickup apparatus according to an output signal of a vibration detecting element for detecting a vibration of the image pickup apparatus; a driver signal generating unit configured to generate a drive signal used to control a driver element to correct a position of a lens, based on an output signal of a position detecting element for detecting the position of the lens to be driven and the vibration-component signal; and a bit length converting circuit for a floating-point number configured to convert the bit length of the output signal of the vibration detecting element expressed by the floating-point number, the bit length converting circuit comprising:
a bit length reducing unit configured to reduce a bit length of an operand expressed by the floating-point number and configured to output the operand to a computing unit; anda bit length increasing unit configured to increase the bit length of a result value of operation represented by the floating-point number inputted from the computing unit and configured to restore an original bit length, wherein said bit length reducing unit discards a predetermined number of higher-order bits of the exponent part of the floating-point number and adds a positive or negative offset value to the exponent part with the higher-order bits discarded, according to an application to be executed by the computing unit, and wherein said bit length increasing unit restores a bit discarded by the bit length reducing unit from the exponent part of the floating-point number and subtracts the offset value from the exponent part thereof, and wherein said vibration-component signal generating unit includes: a high-pass filter configured to filter the output signal of the vibration detecting element, whose bit length has been converted by said bit length converting circuit, with a preset cutoff frequency; and an integration circuit configured to generate the vibration-component signal by integrating an output signal of the high-pass filter, wherein the high-pass filter and the integrating circuit comprises digital filters. |