Vector representation of binary images containing halftone dots

Vector representation of graphics has the advantage that the image can be displayed at any size. When the resolution of a bitmap image is changed, the lack of a line segment arises. In addition, moire occurs when the resolution of an image with halftone dots is changed. We propose a new technique to convert a binary image with halftone dots into its vector representation. Resolution conversion of a binary image can easily be performed without moire by using a continuous tone approximation of the halftone dots. First, we separate the area of halftone dots and line drawings in the image. Next, a continuous tone approximation is applied to the area of halftone dots. Then, conventional vectorization is applied to both continuous tone areas and line drawings. Finally, these components are mixed and reconstructed. Our approach provides an efficient way of displaying cartoon-like images at any size with a limited amount of data.