Abstract: In order to reduce the reconstructed errors, the fast Fourier transform(FFT)-based nearfield acoustic holography requires the measurement aperture at least 2 times larger than the sound source in area. This limitation causes heavy measurement work and makes the FFT-based NAH difficult to be implemented to large-scale source. Based on the analysis of how arithmetic errors generating, a K-space pressure data extrapolation method is introduced into FFT-based NAH, and a new NAH based on K-space data extrapolation method is proposed. The new method can effectively reduce arithmetic errors, therefore it is no need to use a large measurement aperture to reduce the reconstructed errors. The results of numerical simulations and experiment show that the new method can work well in the small measurement aperture, reduce the requirement of measurement aperture’s area, and is convenient for application.

Key words: K-space data extrapolation, Nearfield acoustic holography, Small measurement aperture, Tikhonov regularization method