Memory system using non-linear filtering shceme and read method thereof

Control method for a nonvolatile memory device according to an embodiment of the present invention, ask for the number of memory cells having a threshold voltage between the non-first sampling read voltage and the second sampled read voltage from the volatile memory device to a plurality of sampling values the method comprising, and determining to process through the non-linear filtering operation of the plurality of sampling values ​​in the cell count between the first sampled voltage reading and the second reading voltage sampling.