Abstract
The objective of this study is to improve split method which was previously proposed for image enlargement. The split method was originally designed for image with two levels such as vehicle license image enlargement. Therefore, it might not fit for other purpose. And we noted the original split method as zero-order split method. In this study, a 1st order and 2nd order split method are proposed. For comparison, the proposed methods and several image enlarging methods are tested. There are three sets of test images were used in this study. The first set of images is images degraded from a referential image. The second set of images is low resolution images taken directly from camera. The third set of images is some images frequently used in literature. Further comparison is made between the proposed 2nd order split method and the bi-cubic interpolation method. Results show that the proposed methods are not only simple but also increasing image contrast and clearing image outline.