250

200

150

100

50

0

Gra

y le

vel f

or e

lem

ent j

+1

0 50 100 150 200 250 Gray level for element j

(b)

(a)

Background

Non-ROI ROI

(a) (b) (c)

(d) (e)

(a) (b) (c)

(a)

(b)

(a) (b) (c)

0 5 10 15 20 25 30 35 40 45

10 9 8 7 6 5 4 3 2 1

PSNR (dB)

Imag

es