长江航运业的快速发展导致长江中船舶数量激增,相应的水体噪声污染可能对同水域的长江江豚(Neophocaena asiaeorientalis asiaeorientalis)产生一定的负面影响,本研究采用宽频录音设备对长江和畅洲北汊非正式通航江段的各类常见大型船舶...长江航运业的快速发展导致长江中船舶数量激增,相应的水体噪声污染可能对同水域的长江江豚(Neophocaena asiaeorientalis asiaeorientalis)产生一定的负面影响,本研究采用宽频录音设备对长江和畅洲北汊非正式通航江段的各类常见大型船舶(长> 15 m且宽> 5 m)的航行噪声进行了记录,并分析其峰值-峰值声压级强度(SPLp-p)和功率谱密度(PSD)等。结果表明,大型船舶的航行噪声能量分布频率范围较广(> 100 k Hz),但主要集中于中低频(<10 k Hz)部分,各频率(20 Hz～144 k Hz)处的均方根声压级(SPLrms)对环境背景噪声在该频率处的噪声增量范围为3. 7～66. 5 d B。接收到的1/3倍频程声压级(TOL)在各频率处都大于70 d B,在8～140 k Hz频段内都高于长江江豚的听觉阈值。说明大型船舶的航行噪声可能会对长江江豚个体间的声通讯及听觉带来不利影响,如听觉掩盖。展开更多
We propose a robust blind watermarking algorithm for three-dimensional(3D)mesh models based on vertex curvature to maintain good robustness and improve visual masking in 3D mesh models.In the embedding process,by usin...We propose a robust blind watermarking algorithm for three-dimensional(3D)mesh models based on vertex curvature to maintain good robustness and improve visual masking in 3D mesh models.In the embedding process,by using the local window of vertex,the root mean square curvature is calculated for every vertex of the 3D mesh model and an ordered set of fluctuation values is obtained.According to the ordered fluctuation values,the vertices are separated into bins.In each bin the fluctuation values are normalized.Finally,the mean of the root mean square curvature fluctuation values of the vertices in each bin is modulated to embed watermark information.In watermark detection,the algorithm uses a blind watermark extraction technique to extract the watermark information.The experimental results show that the algorithm has a very good performance for visual masking of the embedded model and that it can resist a variety of common attacks such as vertex rearrangement,rotation,translating,uniform scaling,noise,smoothing,quantization,and simplification.展开更多
文摘长江航运业的快速发展导致长江中船舶数量激增,相应的水体噪声污染可能对同水域的长江江豚(Neophocaena asiaeorientalis asiaeorientalis)产生一定的负面影响,本研究采用宽频录音设备对长江和畅洲北汊非正式通航江段的各类常见大型船舶(长> 15 m且宽> 5 m)的航行噪声进行了记录,并分析其峰值-峰值声压级强度(SPLp-p)和功率谱密度(PSD)等。结果表明,大型船舶的航行噪声能量分布频率范围较广(> 100 k Hz),但主要集中于中低频(<10 k Hz)部分,各频率(20 Hz～144 k Hz)处的均方根声压级(SPLrms)对环境背景噪声在该频率处的噪声增量范围为3. 7～66. 5 d B。接收到的1/3倍频程声压级(TOL)在各频率处都大于70 d B,在8～140 k Hz频段内都高于长江江豚的听觉阈值。说明大型船舶的航行噪声可能会对长江江豚个体间的声通讯及听觉带来不利影响,如听觉掩盖。
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20113227110021)
文摘We propose a robust blind watermarking algorithm for three-dimensional(3D)mesh models based on vertex curvature to maintain good robustness and improve visual masking in 3D mesh models.In the embedding process,by using the local window of vertex,the root mean square curvature is calculated for every vertex of the 3D mesh model and an ordered set of fluctuation values is obtained.According to the ordered fluctuation values,the vertices are separated into bins.In each bin the fluctuation values are normalized.Finally,the mean of the root mean square curvature fluctuation values of the vertices in each bin is modulated to embed watermark information.In watermark detection,the algorithm uses a blind watermark extraction technique to extract the watermark information.The experimental results show that the algorithm has a very good performance for visual masking of the embedded model and that it can resist a variety of common attacks such as vertex rearrangement,rotation,translating,uniform scaling,noise,smoothing,quantization,and simplification.
