1. A method of generating a tomography image, the method comprising: performing a depth scan on one spot on a surface of a subject using modulated light received from a spatial light modulator configured to modulate either one or both an intensity and a phase light received from a light source according to a pattern for each of a plurality of patterns; obtaining depth scan data for each of the plurality of patterns by repeating the depth scan on the spot for each of a plurality of patterns of the spatial light modulator; forming a matrix R representing a vector space based on a correlation of signal values of the depth scan data for each of the plurality of patterns; performing a matrix decomposition on the matrix R; dividing the vector space represented as a sum of subspace components into a noise subspace and a signal subspace based on a matrix obtained by the matrix decomposition; reconstructing a vector space based on either one or both of components of the signal subspace and components of the noise subspace; and generating a tomography image based on the reconstructed vector space.