Analysis of JPEG Digital Image Compression Process
Abstract
JPEG is the most often used image compression standard that is used since 1992. It is a lossy compression method, and is widely used in digital cameras and mobile phones. Depending on the parameters and user needs, it can achieve a compression ratio between 10 and 50. Memory for digital image storage is saved on the expense of decompressed image quality. The method is based on the Discrete Cosine Transform (DCT) that separates the image into its different frequency components. This paper shows how different parameters of the algorithm influence the performance of the compression. In the end, ideas are given how to either increase the compression ratio keeping the same decompressed image quality, or to improve the quality without decreasing the compression ratio. The quality between the original and the decompressed images is measured using two objective criteria: the Peak Signal-to-Noise Ratio (PSNR) and the structural similarity index (SSIM).
References
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