Noriaki SUETAKE^1*, Hideaki KAWANO², Go TANAKA³, Hidenobu HASHIKAMI⁴, and Eiji UCHINO^1,5

¹Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi, Yamaguchi 753-8512, Japan
²Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan
³Graduate School of Natural Sciences, Nagoya City University, Nagoya 467-8601, Japan
⁴Graduate School of Systems and Information Engineering, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
⁵Fuzzy Logic Systems Institute, Iizuka, Fukuoka 820-0067, Japan

(Received August 19, 2011; Accepted September 14, 2011)

In this paper, a new image enlargement method applying the backprojection for lost pixel (BPLP) to the predefined codebook-based method is proposed. BPLP is a method for image restoration. In BPLP, the eigenspace reflecting the characteristics of an input image is generated from the remained pixels and is used to restore the missing pixels. In the proposed method, the eigenspace is replaced by one generated from the predefined codebook (PDC). PDC represents edge-blurring properties in a small image patch and consists of pairs of low- and high-frequency image patches on various edge patterns. By replacing the PDC-based estimation of lost high-frequency components with BPLP, a fast image enlargement method retaining its performance can be developed. Through some experiments, the effectiveness of the proposed method was demonstrated. Especially, it was confirmed that the processing time of the proposed method was shortened to about 1/50 that of the PDC-based method.

Key words: image enlargement, super-resolution, predefined codebook, backprojection for lost pixels, edge pattern, image patch

^*E-mail address: suetake@sci.yamaguchi-u.ac.jp