ABSTRACT
Compound image comprises of the combination of text, graphics and natural images. Compression and transmission of these compound images are the essential processes in the real time applications where segmentation plays a crucial role. Compound image transmission for real-time applications require that the compression technique should not only attains high compression ratio, moreover has low complexity, high PSNR value and a required level of security. Several approaches are being proposed in the past for the process of segmentation and compression of compound images. This paper proposes a novel method for block-based compound image compression. The pictorial blocks and text/graphics blocks are separated from the compound image. The pictorial blocks are compressed using discrete haar wavelet transformation and text/graphics colors are mapped to primary colors using color quantization algorithm and the resulting index values are then compressed using lossless Huffman coding technique. The compressed image is then encrypted using Advanced Encryption Standard algorithm. The proposed model provides several benefits like low complexity, high compression ratio, and a high PSNR value .Moreover it ensures that the transmission is fast and highly secured. Experimental results conclude that the proposed block based segmentation algorithm provides better results, than most of the other image compression techniques.
Keywords: Compound image compression, Haar wavelet transformation, Huffman coding, Advanced Encryption Standard algorithm
1. INTRODUCTION
Internet, fax, mobiles phones etc are the most common communication medium in use nowadays. The information used in these media is in digital format. Transmission of these digital forms of documents is done in a fraction of seconds. High compression and bit rates are required during transmission, to avoid expenses and
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