title: Replacers of barcodes for small application areas by using grating dots to diffractively form bright points.
abstract: Although barcodes can be used to manage data conveniently, they cannot be applied to small areas. Therefore, pointcodes are used to overcome the issue in this article. A pointcode uses a pointcode pattern to encode data and uses a pointcode image to decode data. A pointcode pattern is composed of many grating dots with different specified grating pitches and grating orientations. Moreover, there are two grating-dot sizes generated. When a laser beam illuminates a pointcode pattern with correct illuminating conditions, a pointcode image corresponding to the hidden data is diffractively reconstructed. A pointcode image is composed of many bright points with different positions. There are two possible bright-point sizes generated. A bright point or two bright points at specified positions are used to denote a number. Small pointcode patterns are enough to diffractively form pointcode images.
authors.affiliation: Department of Mechanical Engineering, Lunghwa University of Science and Technology, 300, Section 1, Wanshou Road, Kueishan, Taoyuan County, Taiwan. slyeh@mail.lhu.edu.tw
authors.forename: Sheng Lih
authors.initials: SL
authors.lastname: Yeh
authors.forename: Hung Jen
authors.initials: HJ
authors.lastname: Yang
authors.forename: Shyh Tsong
authors.initials: ST
authors.lastname: Lin
authors.forename: Ming Wei
authors.initials: MW
authors.lastname: Wu