Ideal Huffman Code for Lossless Image Compression for Ubiquitous Access

Abstract

<p>Compression technique is adopted to solve various big data problems such as storage and transmission. The growth of cloud computing and smart phone industries has led to generation of huge volume of digital data. Digital data can be in various forms as audio, video, images and documents. These digital data are generally compressed and stored in cloud storage environment. Efficient storing and retrieval mechanism of digital data by adopting good compression technique will result in reducing cost. The compression technique is composed of lossy and lossless compression technique. Here we consider Lossless image compression technique, minimizing the number of bits for encoding will aid in improving the coding efficiency and high compression. Fixed length coding cannot assure in minimizing bit length. In order to minimize the bits variable Length codes with prefix-free codes nature are preferred. However the existing compression model presented induce high computing overhead, to address this issue, this work presents an ideal and efficient modified Huffman technique that improves compression factor up to 33.44% for Bi-level images and 32.578% for Half-tone Images. The average computation time both encoding and decoding shows an improvement of 20.73% for Bi-level images and 28.71% for Half-tone images. The proposed work has achieved overall 2% increase in coding efficiency, reduced memory usage of 0.435% for Bi-level images and 0.19% for Half-tone Images. The overall result achieved shows that the proposed model can be adopted to support ubiquitous access to digital data.</p>

Selection of compression test images using variance-based statistical method

“…compression level). Here are the main JPEG coding steps: a) Preparation b) TCD (Transform in Discrete Cosine) on 8x8 units c) Quantification d) Zigzag reading e) DC component direct coding (average of 8x8 unit) f) Coding by range of AC component (RLE: Run Length Encoding) g) Entropic coding of Huffman [4] type (variable length coding: VLC). For very high compression coding, we prefer compressing with wavelets or fractals to avoid edge effect which takes place sometimes under the shape of color rings near the remaining clear outlines.…”