A region adaptive encoding algorithm for simple image compression

In this paper, an effective algorithm for compressing simple images, such as cartoons and man-drawn images, is proposed. Compared to existing methods, the proposed algorithm applies several new techniques. First, we classify the regions of an image into 4 classes (uniform, semi-uniform, multiple DCs, and non-uniform). For different classes, different coding algorithms are applied. Second, instead of calculating the average, we apply majority voting to determine DC terms. Moreover, a dividing and 2^nd order polynomial approximation scheme is applied for boundary encoding. Simulations show that, when compressing simple images, the proposed algorithm much outperforms other state-of-the-art algorithms, especially in perception.