Image (a) (b) (c) (d) avg. lr pixels 256Í256 384Í256 256Í256 384Í256 % con. ums 0.705 sec 1.035 sec 0.672 sec 1.017 sec 100 iwf 1492 sec 1658 sec 1384 sec 1625 sec 184441 srm 2393 sec 3566 sec 2497 sec 3241 sec 343608 edums 1.243 sec 1.798 sec 1.238 sec 1.777 sec 177

Table 3: Computational efficiency of conventional ums (con. ums), iterative wiener filter (iwf) [16], sparse representation model (srm) [14], and edums with an upscaling factor of three.