The characteristics of a noncoherent-coherent IR image converter that uses pyroelectric effect in LiNbO3 and the electro-optic effect and photorefraction in Bi12XO20 (X = Ti, Si, Ge) has been analysed theoretically and experimentally. An experimental multilayered structure by which IR radiation can be converted into coherent visible radiation was obtained on the basis of theoretical calculations. The measured threshold sensitivity of the converter similar to 10(-5) W/cm(2), was found to be comparable to theoretical estimates. The limiting resolution of the readout image was about 0.1 lp/mm. The change in the optical properties is estimated by use of the linear equation of an applied electric field (or polarization) that is not excessively strong.