Currently , transforming coding is one of the most used approach for image coding , where the discrete cosine transform ( dct ) , the discrete wavelet transform ( dwt ) , and the lapped biorthogonal transform ( lbt ) are widely utilized . how to reduce the complexity of these discrete transforms , is the key technique to image compression . in this thesis , a type of lapped biorthogonal transform which can map integers to integers is considered 变换编码是图像压缩中的主流方法,其采用的主要变换有离散余弦变换、离散小波变换、双正交叠式变换,如何减少这些离散变换的计算复杂性,一直是图像压缩研究的重要课题。
Transform coding is a type of data compression for "natural" data like audio signals or photographic images. The transformation is typically lossy, resulting in a lower quality copy of the original input.