Spatiotemporal spectral coding of stereo image sequences

This paper presents a new compression scheme for interlaced stereoscopic sequences which differentiates between a region of fixation and a peripheral area, and thereby compacts the stereoscopic information into the spectral space of a monocular video channel. Spectral compression is achieved by avoiding transmitting high-frequency information over the entire images, but only within and around the region where the observer acuity is the highest. The proposed approach consists of decomposing the left and right fields of the stereoscopic pairs into low-pass and high-pass components. High-frequency components are then limited to a fixation region, thus allowing a reduction of their spectral extent. A composite video signal is then formed by positioning the different components into the available spectral space through filtering and modulation. The approach is compatible with the NTSC standard in the sense that the same color subcarrier and the same spectral region are used for the chrominance components. Strategies are proposed for the estimation of the fixation region, based upon a psychophysical study on visual strategies during depth discrimination tasks.