1. Field of the Invention
The present invention relates to an audio signal processing apparatus.
2. Description of the Related Art
Conventionally, as an audio signal processing apparatus, image pickup apparatuses such as cameras, which can pick up moving images, are known. Each of these image pickup apparatuses drives driven units such as, for example, a lens, diaphragm, and the like, which units are incorporated in itself, so as to pick up a moving image. Driving noise generated at that time is mixed in an audio signal, and an audio signal which is not required by the user may be unwantedly recorded. To solve this problem, various proposals have been conventionally made.
In Japanese Patent Laid-Open No. 2006-203376, a digital camera switches noise processing methods according to an operation time period of a motor used to adjust an optical system. Thus, noise processing is executed according to the motor operation time period, thereby obtaining a high-quality audio signal. More specifically, when the motor operation time period is long, the digital camera reduces noise using a low-pass filter; when the motor operation time period is short, it executes processing for superimposing an audio signal immediately before the motor operation on that during a noise generation period.
Japanese Patent Laid-Open No. 2006-203376 considers the motor operation time period, but it does not consider types of noise generation sources. That is, the digital camera simply switches types of noise processes according to the length of the operation time period irrespective of types of noise generation sources. Therefore, flexibility associated with switching of the noise processes is limited.