A new apparatus used for optical image subiraotion wiih periodic whiie light linear sources is proposed. Provided thai filament interval,grating spatial frequency,periodic polarization spatial filtering are matched each other, the brightness of coded image will be increased greatly. Beoause of high redundenoy of -the system, the inflnenoe of pola-riza-fcion degree and phase inhomogeneiiy of sheet polarization filter oould be considerably reduced. Bo, high SNR subtraofcion outpxii could, be obtained. In this paper, property of coded image and requirement for ilie system are discussed with spatial coherent imaging theory. Procedure of light transmission and filiering, shifting of carrier are calculated with matrix method. Decode method by using optics and electronics is disoribed.Finally, desirable experimental result is presented.