Table 3. Comparison of the correlation coefficients of the proposed scheme with the other methods

Method	Correlation coefficients
	Horizontal	Vertical	Diagonal
Proposed algorithm	0.005794	0.005644	0.003480
Ref.[1]	0.077000	-0.072360	-0.061530
Ref.[2]	0.003200	0.002424	0.001520
Ref.[3]	0.006300	0.005900	0.007300
Ref.[4]	-0.001700	0.005900	-0.001900
Ref.[5]	-0.044500	0.004100	Not specified
Ref.[6]	0.004800	0.002700	0.003600
Ref.[7]	-0.097360	-0.070680	0.048440
Ref.[8]	0.011830	0.001600	0.014800