Progressive versus Interlaced Coding

Interlaced versus progressive scanning is an important issue when dealing with digital television. Not only because the change from analog to digital communication may be seen as an opportunity to move to other formats, but also because of the well-known artifacts of interlaced scanning (interline twitter, line crawling, and field aliasing) compared to the natural way of representing two-dimensional images as the progressive format does. However, digital broadcasting has to face the problem of transmitting twice the number of pels of the progressive format. It is the purpose of this article to study this problem, and especially to check if the increased vertical and temporal correlations of the progressive pictures provide a significant improvement in the bit-rate reduction efficiency. In that case, progressive scanning may also be used as an intermediate transmission format to improve the compression performances of interlaced sequences. 1. Introduction Interlaced scanning was introd..

Vestibular stimulation by 2G hypergravity modifies resynchronization in temperature rhythm in rats

International audienceInput from the light/dark (LD) cycle constitutes the primary synchronizing stimulus for the suprachiasmatic nucleus (SCN) circadian clock. However, the SCN can also be synchronized by non-photic inputs. Here, we hypothesized that the vestibular system, which detects head motion and orientation relative to gravity, may provide sensory inputs to synchronize circadian rhythmicity. We investigated the resynchronization of core temperature (Tc) circadian rhythm to a six-hour phase advance of the LD cycle (LD + 6) using hypergravity (2 G) as a vestibular stimulation in control and bilateral vestibular loss (BVL) rats. Three conditions were tested: an LD + 6 exposure alone, a series of seven 2 G pulses without LD + 6, and a series of seven one-hour 2 G pulses (once a day) following LD + 6. First, following LD + 6, sham rats exposed to 2 G pulses resynchronized earlier than BVL rats (p = 0.01), and earlier than sham rats exposed to LD + 6 alone (p = 0.002). Each 2 G pulse caused an acute drop of Tc in sham rats (−2.8 ± 0.3 °C; p < 0.001), while BVL rats remained unaffected. This confirms that the vestibular system influences chronobiological regulation and supports the hypothesis that vestibular input, like physical activity, should be considered as a potent time cue for biological rhythm synchronization, acting in synergy with the visual system