Asimpleandeffectivegreedyalgorithmforimageapproximationisproposed.Basedonthematchingpursuitapproach,itischaracterizedbyareducedcomputationalcomplexitybenefitingfromtwomajormodifications.First,ititerativelyfindsanapproximationbyselectingMatomsinsteadofoneatatime.Second,theinnerproductcomputationsareconfinedwithinonlyafractionofdictionaryatomsateachiteration.Themodificationsareimplementedveryefficientlyduetothespatialincoherenceofthedictionary.Experimentalresultsshowthatcomparedwithfullsearchmatchingpursuit,theproposedalgorithmachievesaspeed-upgainof14.4～36.7timeswhilemaintainingtheapproximationquality.
