Note that, although, in the above-described embodiment, the processing device 201 generates the inverse filters Linv and Rinv, the processing device 201 is not limited to a processing device that generates the inverse filters Linv and Rinv. For example, the processing device 201 is suitable for a case where it is necessary to perform processing to normalize a sound pickup signal appropriately.

A part or the whole of the above-described processing may be executed by a computer program. The above-described program can be stored using any type of non-transitory computer readable medium and provided to the computer. The non-transitory computer readable media include various types of tangible storage media. Examples of the non-transitory computer readable medium include a magnetic storage medium (such as a floppy disk, a magnetic tape, and a hard disk drive), an optical magnetic storage medium (such as a magneto-optical disk), a CD-ROM (Read Only Memory), a CD-R, a CD-R/W, and a semiconductor memory (such as a mask ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), a flash ROM, and a RAM (Random Access Memory)). The program may be provided to a computer using various types of transitory computer readable media. Examples of the transitory computer readable medium include an electric signal, an optical signal, and an electromagnetic wave. The transitory computer readable medium can supply the program to a computer via a wired communication line, such as an electric wire and an optical fiber, or a wireless communication line.

Although the invention made by the inventors are specifically described based on embodiments in the foregoing, it is needless to say that the present invention is not limited to the above-described embodiments and various changes and modifications may be made without departing from the scope of the invention.