Study of hydrogen and deuterium emission characteristics in laser-induced low-pressure helium plasma for the suppression of surface water contamination

An experimental study was conducted in search of the experimental condition required for the much needed suppression of spectral interference caused by surface water in hydrogen analysis using laser-induced low-pressure helium plasma spectroscopy. The problem arising from the difficulty in distinguishing hydrogen emission from hydrogen impurity inside the sample and that coming from the water molecules was overcome by taking advantage of similar emission characteristics shared by hydrogen and deuterium demonstrated in this experiment by the distinct time-dependent and pressure-dependent variations of the D and H emission intensities from the D-doped zircaloy-4 samples. This similarity allows the study of H impurity emission in terms of D emission from the D-doped samples and thereby separating it from the H emission originating from the water molecules. Employing this strategy has allowed us to achieve the large suppression of water induced spectral interference from the previous minimum of 400 microg/g to the current value of 30 microg/g when a laser beam of 34 mJ under tight focusing condition was employed. Along with this favorable result, this experimental condition has also provided a much better (about 6-fold higher) spatial resolution, although these results were achieved at the expense of reducing the linear calibration range from the previous 4 300 microg/g to the present 200 microg/g.     

No-Reference PSNR Estimation for Quality Monitoring of Motion JPEG2000 Video Over Lossy Packet Networks

In this paper, we propose a no-reference (NR) method for estimating the degradation of Motion JPEG2000 (MJP2) video due to packet loss. The proposed method estimates the peak signal-to-noise ratio (PSNR) between received MJP2 frames affected by packet loss and the originally encoded frames without having information about the latter. The PSNR of a frame could be estimated in the wavelet domain, namely before the JPEG2000 decoding process, by utilizing adjacent frames that possess similar amounts of wavelet energy. Simulation results showed that the estimated PSNR is very close to the true value obtained by the full-reference calculation. Our method can be used to monitor the video quality in an IP-based transmission of MJP2, as well as for automatic judgment of error control in streaming applications, or in video broadcasting. For example, if the PSNR of a frame does not reach a predefined level, the frame will be rejected before the decoding process or it will be processed by a concealment techniques before being displayed.