| Summary: | 碩士 === 國立交通大學 === 資訊科學與工程研究所 === 99 === In this study, three kinds of line-type computer art images are created, called line-based Cubism-like image, strip-based Futurism-like image, and rectangle-based Neo-Plasticism-like image. Also proposed are three data hiding techniques for covert communication via these types of art images, respectively.
In the creation of line-based Cubism-like images, the longer line segments in a source image are detected and rearranged to form a new 3D-like shape for each color component in the image. In a process of re-coloring the regions in the new image, a data hiding technique is designed skillfully to embed a secret message into the image by keeping the average color of the region unchanged.
In the strip-based Futurism-like image creation process, the boundary chain codes of each region yielded by image segmentation are utilized to analyze the region characteristics such as corner points and region directions. By drawing the edges formed by the found corner points, an effect of polygon approximation of the prominent regions in the source image is obtained. Then, each region is partitioned into strips in accordance with the extracted region direction, and a given secret message is hidden into the resulting image by coloring the strips with the white color or the region’s average color in a random fashion.
To generate a rectangle-based Neo-Plasticism-like image, a binary space-partition scheme is used to partition a given image into multiple rectangles with the maximum mutual information. Furthermore, two methods are proposed to hide a secret message into the generated art image. One is to limit the image partitioning directions (horizontal and vertical) to follow an alternative order and hide the secret messages into the leaf nodes of a partition tree yielded by the binary space-partition scheme. The other method does not limit the partitioning direction order, and fills the regions with horizontal or vertical color lines to embed the secret message.
In addition, for each art image, the user is allowed to select some parameters to create his/her favorite art images. Various security enhancement measures are also proposed to make the embedded data more random to prevent hackers’ attacks. Experimental results showing the feasibility of the proposed methods for art image creation and data hiding applications are also included.
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