1. A method of extracting a sound source acoustic image body in 3D space, the method comprising: step 1, determining a spatial position of a sound source acoustic image, which is achieved by: processing time-frequency conversion for a signal of each channel and processing the same sub-band division for each channel by a microprocessor; and with the listener as a spherical coordinate system origin, for a speaker with the horizontal angle μ i and elevation angle η i , setting a vector p i (k,n) representing the time-frequency representation of the corresponding signal, p i ⁡ ( k , n ) = g i ⁡ ( k , n ) · [ cos ⁢ ⁢ μ i · cos ⁢ ⁢ η i sin ⁢ ⁢ μ i · cos ⁢ ⁢ η i sin ⁢ ⁢ η i ] wherein i refers to an index value of the speaker, k refers to a frequency band index, n refers to a time domain frame number index, g i (k,n) refers to a intensity information of a frequency domain point; the horizontal angle μ i and elevation angle η i is calculated using the following formula, tan ⁢ ⁢ μ ⁡ ( k , n ) = ∑ i = 1 N ⁢ ⁢ g i ⁡ ( k , n ) · cos ⁢ ⁢ μ i · cos ⁢ ⁢ η i ∑ i = 1 N ⁢ ⁢ g i ⁡ ( k , n ) · sin ⁢ ⁢ μ i · cos ⁢ ⁢ η i tan ⁢ ⁢ η ⁡ ( k , n ) = [ ∑ i = 1 N ⁢ ⁢ g i ⁡ ( k , n ) · cos ⁢ ⁢ μ i · cos ⁢ ⁢ η i ] 2 + [ ∑ i = 1 N ⁢ ⁢ g i ⁡ ( k , n ) · sin ⁢ ⁢ μ i · cos ⁢ ⁢ η i ] 2 ∑ i = 1 N ⁢ ⁢ g i ⁡ ( k , n ) · sin ⁢ ⁢ η i wherein, N refers to a total number of the speakers, i values for 1, 2. .. N, μ(k, n), η(k, n) i.e., the horizontal angle μ and elevation angle η of the sound source acoustic image in k-th frequency band of the n-th frame; a distance ρ from the sound source acoustic image audio to the origin of the spherical coordinate system takes the average distance of distances from all the speakers to the listener; step 2, determining the speaker beside the spatial position by a microprocessor where the sound source acoustic image is located according to the determined spatial position (ρ, μ, η) of the sound source acoustic image; step 3, calculating a correlation of signals of all sound tracks of the speakers selected at step 2 in the horizontal direction and the vertical direction by a microprocessor, which is achieved by: dividing the selected speakers into left part and right part according to the location of the acoustic image, using a vertical plane of the connecting line between the sound source acoustic image and the listener as a projection plane, calculating a sum of the components of the left and right signals which are perpendicular to the projection plane respectively, denoting the sums as P L and P R respectively, and calculating the correlation IC H of the left and right signals as follows, IC H = cov ⁡ ( P L , P R ) cov ⁡ ( P L , P L ) · cov ⁡ ( P R , P R ) dividing the selected speakers into upper part and lower part according to the location of the acoustic image, using a horizontal plane where the sound source acoustic image and the listener are located as a projection plane, calculating a sum of the components of the upper and lower signals which are perpendicular to the projection plane respectively, denoting the sums as P U and P D respectively, and calculating the correlation IC V of the upper and lower signals as follows, IC V = cov ⁡ ( P U , P D ) cov ⁡ ( P U , P U ) · cov ⁡ ( P D , P D ) step 4, obtaining and storing a parameter set {IC H , IC v , Min{IC H , IC v }} of the acoustic image body in a storage medium, wherein the Min{IC H , IC v } is a smaller value between IC H and IC v .