Light field cameras have been recently shown to be very effective in applications such as digital refocusing and 3D reconstruction. In a single snapshot these cameras provide a sample of the light field of a scene by trading off spatial resolution with angular resolution. Current methods produce images at a resolution that is much lower than that of traditional imaging devices. However, by explicitly modeling the image formation process and incorporating priors such as Lambertianity and texture statistics, these types of images can be reconstructed at a higher resolution. We formulate this method in a variational Bayesian framework and perform the reconstruction of both the surface of the scene and the (superresolved) light field. The method is demonstrated on both synthetic and real images captured with our light-field camera prototype.

Portable wearable devices that assess energy expenditure during intermittent exercise and recovery would be useful in team sports. Fourteen state-level male rugby union players (mean ± SD: age, 22 ± 4 years; body mass, 88.8 ± 11.2 kg; height, 1.81 ± 0.07 m, body fat, 18 ± 6%) participated in this study. Energy expenditure was measured by the SenseWear Armband (SWA) and validated against indirect calorimetry as the criterion measure during a 42-minute rugby-specific intermittent exercise test and an immediate postexercise 10-minute recovery period. Energy expenditure measurements from indirect calorimetry and the SWA were only moderately correlated during both the exercise test (r = 0.55, ±0.34; mean, ±90% confidence limits) and recovery period (r = 0.58, ±0.33). The SWA estimate of energy expenditure during exercise was unclear, with a mean bias of -1.9% (±5.3%), and during recovery energy expenditure was overestimated, with a mean bias of 17% (±12%) at the mean estimated energy expenditure. Typical error of SWA energy expenditure estimates expressed as a coefficient of variation (±90% confidence interval) was 10% (8-16%) during exercise and 19% (14-30%) during recovery. The SWA did not provide a valid measure of energy expenditure during rugby-specific intermittent exercise or 10-minute postexercise recovery. Further improvements are required in the performance of the SWA before it can be used routinely in intermittent sports and provide worthwhile information in relation to workloads of athletes for sport scientists and coaches.

The aim of this study was to investigate the relationship between reactive strength in a vertical and a horizontal drop jump (DJ). Subjects (n = 28) with previous jump training experience, performed 6 vertical DJs and 6 horizontal DJs from a 0.4-m box. Contact time, height jumped, distance jumped, and reactive strength index (RSI) were calculated and analyzed. Typical error measurements (TEMCV%) and intraclass correlations (ICCs) were used to assess the intrasubject reliability. Relationships between jumps and within jumps of the aforementioned variables were assessed using ICCs. The ICC (r > 0.789) and the TEMCV% (<10%) indicated good reliability for both vertical and horizontal DJs across each variable. Contact time showed no relationship between jumps (r = 0.222) and had no effect on the vertical DJ height (r = 0.152) or horizontal DJ distance (r = 0.261). The RSI correlation (r = 0.533) indicated a large relationship between reactive ability in the horizontal DJ and the vertical DJ. Contact times were significantly lower in vertical DJs compared with horizontal DJs (p < 0.0001). This study indicated that horizontal DJs are reliable and may be better used to train reactive movements that do not require brief contact times.