1. A data processing apparatus comprising at least one data processor configured to provide: a signal to noise (SNR) distribution data generating function which generates SNR distribution data of processing target data; a filter processing function which generates filter processed data obtained by performing filter processing on the processing target data to improve a SNR of the processing target data based on windowing information to be used in a subsequent window transformation; a weighting function generating function which generates a weighting function based on the SNR distribution data; and a corrected data generating function which generates corrected data by performing weighted calculation between the processing target data and the filter processed data using the weighting function, wherein said at least one data processor is further configured to provide: a setting function configured to automatically set at least one of a window width, a window level and a gamma curve as the information used for the window transformation synchronously based on an operation of an input device, as a preset value or according to a predetermined condition; and a display function configured to display data generated on the corrected data when the information used for the window transformation is synchronously set based on operation of the input device.