We investigated theoretically and experimentally different conditions of the Bragg synchronism and mismatch of the acousto-optic interaction to obtain edge enhancement in optical images in different diffraction orders. For the first time it is shown that by adjusting the Bragg mismatch, it is possible to obtain the image edge enhancement not only in the 0th but also at the +1st diffraction order. This 1st diffraction order can be more preferable than the 0th order due to the possibility to obtain any level of the edge enhanced signal (from 0 to 100%), to modulate the signal, to effectively reduce the noise, to filter other unwanted signals. Optical image created by He-Ne laser radiation (lambda = 0.63 micron) passed through a Fourier system consisting of two lenses.