title: Contact screen image subtraction technique.
abstract: Experimental results have clearly demonstrated that the newly proposed optical contact screen pulse-width modulation image subtraction technique can be used for the evaluation both qualitative and quantitative of the subtle differences between two similar images.
authors.forename: D
authors.initials: D
authors.lastname: Zhao
authors.forename: C K
authors.initials: CK
authors.lastname: Chiang
authors.forename: H K
authors.initials: HK
authors.lastname: Liu