Apparatus and method for inverse transforming the either, or transform representation transformed into transform representation
This multi-dimensional lifting scheme is prevented accumulation of the approximation errors and lossless integer transform by applying each obtained as a result, also obtained inverse integer transform.
Abstract
For converting first and second blocks of discrete values to transform representation, the first block is transformed in accordance with the first conversion rule (102) is then rounded (104). Then, the converted value rounded, is summed with the second block of the original individual values (106), then processes the total result according to the second transformation rule (108). Output value of the conversion via the second conversion rule is again rounded (110), then, is subtracted from the original individual values of the first block of discrete values (112), the integer output values of the transformed representation of the block can be obtained. This multi-dimensional lifting scheme, but the same transformation rule, sum and subtraction when the signs are different conversion rules the reversed order is possible lossless integer transform by applying each obtained as a result, also obtained inverse integer transform It is. In contrast to the conversion of separation during rotation, on the one hand to significantly reduce the complexity of the calculations, on the other hand it is prevented accumulation of the approximation errors.