Degradation compensator includes a compressor which generates a block-level compression stress matrix (“BCSM”) representing a degradation level of a block included in a frame by R, G, and B input signals of the block, an updater update a frame-level accumulated compression stress matrix (“FACSM”) by adding the BCSM, an error corrector which executes error-correction encoding to elements of a block-level accumulated compression stress matrix (“BACSM”) included in the FACSM, writes encoded elements as a storage data of a non-volatile memory device when a power supply is stopped, executes error-correction decoding to the storage data and writes the decoded storage data as the FACSM of the volatile memory when the power supply is started, a restorer which generates a block-level accumulated stress matrix (“BASM”), and an internal compensator which generates compensated R, G, and B output signals.