Digital Image Processing

V. Hariprasad ¹, S. Kavitha ²

Affiliations
1 The Oxford College of Engineering, Bommanahalli, Bangalore-68, IN
2 Dept. of CSE, The Oxford College of Engineering, Bommanahalli, Bangalore-68, IN

Abstract

This paper presents the analysis of hybrid wavelet transform generation technique using two orthogonal transforms. The orthogonal transforms are used for analysis of global properties of the data into frequency domain. For understanding the local properties of the signal, the concept of wavelet transform is introduced. Wavelets are mathematical tools that can be used to extract information from many different kinds of data such as text and images. The proposed method considers the Hybrid Wavelet transform which can be generated by crossbreeding any two orthogonal transforms among four transforms such as Discrete Cosine transform (DCT), Discrete Walsh transform (DWT), Discrete Hartley transform (DHT) and Discrete Kekre transform (DKT). The analysis of the hybrid wavelet transforms is done by comparing them with the original orthogonal transforms with respect to Mean Square Error (MSE) and Peak Signal to Noise Ratio(PSNR) values. The experimental result increases the performance of Hybrid wavelet transforms than the original orthogonal transforms by maintaining both the compression rate and the quality in tolerable manner.

Keywords

Hybrid Wavelet Transforms, Image Compression, Orthogonal Transforms.

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S. Kavitha ¹, N. Ramaraj ²

Affiliations
1 Computer Science & Engineering Department, The Oxford College of Engineering, VTU, Bangalore, IN
2 GKM College of Engineering, Chennai, Anna University, IN

Abstract

The popularity of multimedia applications has resulted in development of lossless and lossy compression techniques. This paper presents a novel lossy compression scheme for the Low Depth-of-Field (DOF) images where the quality factor is altered based on whether we are compressing object-of-interest (OOI) or the background. Low DOF is a popular photographic technique which enables the representation of the photographer’s intention by giving a clear focus only on an object of interest (OOI). We first describe a fast and efficient scheme for extracting OOIs from individual low-DOF images and then apply the lossy compression scheme with different quality factor on it. The proposed system does not require any user assistance to determine the initial OOI. The experimental results shows that the proposed method performs well in compressing the given image (higher compression ratio), at the same time maintaining the acceptable quality (high PSNR) and reduce the complexity.

Keywords

Image Compression, JPEG, Image Segmentation, Low Depth-Of-Field (DOF), Object of Interest (OOI).

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