Abstract: Microphone array-based acoustic imaging technology is widely used in noise source localization and other applications.A large number of microphone arrays are typically needed to achieve higher spatial resolution.In this paper,we propose a high-resolution imaging algorithm in the domain of difference coarray of planar microphone arrays is proposed,which aims to decrease the number of microphone arrays employed in the current acoustic imaging systems.By applying the proposed method to a two-dimensional nested array,a uniform rectangular array with a significantly higher degree of freedom can be obtained in the difference coarray domain.Through the new algorithm,a high-resolution acoustic imaging with a relatively small number of microphones is achieved.In comparison to the acoustic imaging technique based on a standard planar array,which needs 81 elements for traditional beamforming,simulation results demonstrate that the proposed method employs 49 elements to realize an even less main lobe width.Additionally,the positioning accuracy of the proposed algorithm is higher at a low signal-to-noise ratio.