Distortion estimators



DWT K_b = 4 mid-point estimators


P	δ		D^sig	∆D^sig		D^ref	∆D^ref

3	0.5	149.333	144.0
2	0.5	37.333	36.0	5.333	4.0
1	0.5	9.333	9.0	1.333	1.0
0	0.5	2.333	2.25	0.333	0.25