1. A data processing apparatus comprising: a SNR distribution data generating unit configured to generate SNR distribution data of processing target data based on the processing target data; a filter processing unit configured to generate filter processed data obtained by performing filter processing to the processing target data to improve a SNR of the processing target data; a weighting function generating unit configured to generate a weighting function based on the SNR distribution data; and a corrected data generating unit configured to generate corrected data by performing weighted calculation between the processing target data and the filter processed data using the weighting function.