1. An image reconstructing method comprising: forming an interference pattern by interference of a reference beam and an object beam, the object beam including information about an object; detecting the interference pattern with a detector having a plurality of regions, each region including at least a first sub-region and a second sub-region of which sensitivities are different from each other, first forward Fourier transforming a first data set which is detected by a plurality of the first sub-regions of the detector to obtain a first Fourier spectrum including a first-order diffracted light; first inverse Fourier transforming the first-order diffracted light of the first Fourier spectrum to obtain first amplitude data for each of the first and second sub-regions; second forward Fourier transforming a second data set which is detected by a plurality of the second sub-regions of the detector to obtain a second Fourier spectrum including a first-order diffracted light; second inverse Fourier transforming the first-order diffracted light of the second Fourier spectrum to obtain second amplitude data for each of the first and the second sub-regions; forming a first image by using the first amplitude data for each of the first and second sub-regions, a first portion of the first image having an amplitude value more than a threshold value being removed from the first image; forming a second image by using the second amplitude data for the first portion; and forming a reconstructed image of the object by using the first and second images.