Image compression using dtocs and neighborhood masks along threshold boundaries

In this paper, a new image compression method is presented. It utilizes the DTOCS (Distance Transform on Curved Space) introduced in [Toi92) and [Toi93]. Masks of different sizes are used near threshold boundaries to select optimal places for new control points. The presented method is a considerable improvement to the method presented in [Toi93] and gives better compression ratios. Especially when the number of control points is kept low the difference is 1.5-2 dB in signal-to-noise ratio and it is visually quite clear. The decompression is done by a new method introduced in [Toi93]. It is an interpolation method based on a set of structuring elements.