Antialiasing Scalable Video with a Modulated Lifting Structure

A key problem existing in scalable video based on wavelet transforms is the incidence of aliasing at reduced spatial resolutions. The problem exists because of a fundamental limit in the design of wavelet filters. However, typical video frames are observed to have a strong rolloff in the high frequencies before the Nyquist frequency, which we term the "deadzone". In this paper, we propose a transform that not only exploits this property, but replicates the property in successive DWT levels. The transform is created by modifying the lifting implementation of any regular discrete wavelet transform with two additional modulated lifting steps. The two steps act to transfer aliased content from the low pass band into the deadzone of the high pass band. The proposed transform still retains the property of perfect reconstruction. Visual confirmation shows that the transform performs well in antialiasing at half resolution. However, currently the modulated lifting transform exacts a significant coding penalty relative to baseline DWT compression.