Image sequence processing for videowall visualization

A new processing scheme for large high-resolution displays such as Videowalls is proposed in this paper. The scheme consists in a deinterlacing, an interpolation and an optional enhancement algorithm; its hardware implementation requires a low computational cost. The deinterlacing algorithm is motion- adaptive. A simple hierarchical three-level motion detector provides indications of static, slow and fast motion to activate a temporal FIR filter, a three-tap vertico-temporal median operator and a spatial FIR filter respectively. This simple algorithm limits the hardware requirements to three field memories plus a very reduced number of algebraic operations per interpolated pixel. Usually linear techniques such as pixel repetition or the bilinear method are employed for image interpolation, which however either introduce artifacts (e.g. blocking effects) or tend to smooth edges. A higher quality rendition of the image is obtained by the concept of the Warped Distance among the pixels of an image. The computational load of the proposed approach is very small if compared to that of state-of-the-art nonlinear interpolation operators. Finally the contrast enhancement algorithm is a modified Unsharp Masking technique: a polynomial function is added to modulate the sharpening signal, which allows to discriminate between noise and signal and, at the same time, provides an appropriate amplification to low-contrast image details.