Acoustic camera

1. An acoustic camera comprising

a first sound pick-up device and a second sound pick-up device both installed in said acoustic camera and used to pick up a sound source of a detected object;

a switch respectively connecting to said first sound pick-up device and said second sound pick-up device and used to select said first sound pick-up device or said second sound pick-up device to pick up a sound source of a detected object; and

a data-retrieving system connecting to said first sound pick-up device and said second sound pick-up device, receiving signals of a sound source of a detected object, processing said signals, and outputting processing results to a display module.

2. The acoustic camera according to claim 1 , wherein said data-retrieving system includes an acoustic inverse computation module, a delay-and-sum module, and an acoustic post-processor.

3. The acoustic camera according to claim 2 , wherein said first sound pick-up device is used to pick up a near-field sound field in a near-field mode.

4. The acoustic camera according to claim 3 , wherein said first sound pick-up device has a first microphone array containing a plurality of microphones.

5. The acoustic camera according to claim 4 , wherein when picking up a near-field sound field in said near-field mode, a highest sound frequency said acoustic camera can detect satisfies an equation:

f

max

=

c

2

⁢

d

Wherein d is a distance between two adjacent said microphones, and c is a velocity of wave (m/s), and f max is said highest sound frequency (Hz).

6. The acoustic camera according to claim 3 , wherein when picking up a near-field sound field in said near-field mode, said first sound pick-up device picks up a sound source of a detected object and outputs a sound field of said sound source to said data-retrieving system, and said acoustic inverse computation module of said data-retrieving system obtains source strength of said sound source of said detected object, and said acoustic post-processor obtains sound pressure, particle velocity, sound intensity and sound power of said sound source of said detected object; said source strength, said sound pressure, said particle velocity, said sound intensity and said sound power are output to said display module.

7. The acoustic camera according to claim 2 , wherein said second sound pick-up device is used to pick up a far-field sound field in a far-field mode.

8. The acoustic camera according to claim 7 , wherein said second sound pick-up device has a second microphone array containing a plurality of microphones; said second microphone array is a rectangular microphone array has first sides and second sides, and a length of each of said first sides is smaller than or equal to a length of each of said second sides.

9. The acoustic camera according to claim 8 , wherein when picking up a far-field sound field in said near-field mode, a lowest sound frequency said acoustic camera can detect satisfies an equation:

f

min

=

c

D

,

Wherein D is said length of each of said first sides, and c is velocity of wave (m/s), and f min is said lowest sound frequency (Hz).

10. The acoustic camera according to claim 7 , wherein when picking up a far-field sound field in said far-field mode, said second sound pick-up device picks up a sound source of a detected object and outputs a sound field of said sound source to said data-retrieving system; said delay-and-sum module of said data-retrieving system works out a strength of said sound source and outputs said strength to said display module.

11. The acoustic camera according to claim 1 , wherein said display module is a display screen.