a signal acquisition unit configured to acquire a second signal by detecting a first signal as a real world signal of a first dimension by a sensor,

wherein said sensor has a plurality of detection elements each having a spatial integrating effect,

said second signal being of a second dimension lower than said first dimension and containing distortion with respect to said first signal; and

a signal processing unit configured to process said second signals to generate a third signal comprised of a plurality of detection signals alleviated in spatial integrating effects, as said distortion, caused by projection considering integrating effects in unit of smaller size than a detection element sizes,

wherein said sensor is arrayed in a predetermined direction, which is at least one direction;

said signal processing unit includes a correlation detection unit configured to detect the correlation between two sample data of said second signal neighboring to each other in said predetermined direction; and

a double-density sample generating unit configured to generate, for respective considered sample data,

a first sample value, as a sample value of higher correlation, based on a sample value of a side of higher correlation of said two neighboring sample data,

a second sample value, as a sample value of a side of lower correlation, based on sample values of said considered sample data and said first sample value, and

outputting said first and second sample values as two sample values of said third signal corresponding to said sample under consideration.