The technology of the laplacian sharpening effect is applied in the real-time photoelectronic joint transform correlator. Through sharpening process of joint transform power spectrum plane, it improves Yong′s interference fringes contrast of joint transform power spectrum. The constrast of correlation peak is enhanced,and the ratio of target recognition is also improved greatly. The experimental results indicate that the lowest limitation of detected target contrast used by this technology is about 0.5%. Th...