Overlapping DCT for image compression
نویسنده
چکیده
Current research in image compression (wavelets, local trigono-metric bases, JPEG, etc.) centres on adaptive coding of the grey levels of the image. These methods may be described as using band-limiting procedures with a band-limit that depends on the local properties of the image. This paper looks at the non-adaptive use of Discrete Cosine Transforms in blocks, with uniform band-limits over the whole image. The relationship between compressed Cosine Transforms and interpolation is used to establish a new type of lapped Cosine Transform, allowing high compression of images without the well-known \quilting" eeect of JPEG-style compression. The method is recommended whenever the end-product of compression is a low resolution image: it is fast and easily programmed, and achieves results comparable with the best wavelet compression methods.
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