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An imaging accuracy improving method is established,within which a distance coefficient including location information between sparse array configuration and the location of defect is proposed to select higher signalto-noise ratio data from all experimental data and then to use these selected data for elliptical imaging.The relationships among imaging accuracy,distance coefficient and residual direct wave are investigated,and then the residual direct wave is introduced to make the engineering application more convenient.The effectiveness of the proposed method is evaluated experimentally by sparse transducer array of a rectangle,and the results reveal that selecting experimental data of smaller distance coefficient can effectively inprove imaging accuracy.Moreover,the direct wave difference increases with the decrease of the distance coefficient,which implies that the imaging accuracy can be effectively improved by using the experimental data of the larger direct wave difference.