1. A system, comprising: a sampler configured to obtain a sampled distribution by sampling a group of cells in solid state storage; an axis locator configured to locate a maximum in the sampled distribution and determine an axis of symmetry at the located maximum; and a distribution processor configured to: generate a conditional distribution associated with the group of cells by copying and flipping a portion of the sampled distribution about the determined axis of symmetry; and estimate an optimal read threshold based on a difference between the sampled distribution and the conditional distribution at a read threshold voltage value.