Direct image resampling using block transform coefficients

摘要

A new efficient method for interpolation and decimation of images by arbitrary ratio using block transform coefficients such as discrete cosine transform (DCT) is obtained. Due to multiple standards in image/video coding schemes, it is expected that decoders as well as display or recording devices need to convert the received signal from one format to another. It is essential that high quality resampling be done in lowest hardware complexity since such processing normally requires a large amount of computations. In this paper, a block based non-integer ratio resampling algorithm is developed which can be implemented very efficiently without significant increase of system complexity. For the implementation of the proposed approach, an inverse block transform (for example, inverse DCT) and resampling process are combined into one process so that no additional processing stage is required. The proposed approach called truncated overlap-add with compensation (TOAC) technique provides cost effective solution to resampling problems. It can be implemented on a single VLSI chip together with inverse block transform operations.