More attention has been paid to the study of video object segmentation in compressed domain these years, which has already led to some practical technology. In this paper, a scheme is put forward for segmentation of h...More attention has been paid to the study of video object segmentation in compressed domain these years, which has already led to some practical technology. In this paper, a scheme is put forward for segmentation of head-shoulder video in MPEG (Motion Picture Experts Group) compressed domain. The conception of DCT (Discrete Cosine Transform) feature plane is defined. In the suggested scheme, firstly, the face region is detected by clustering skin-tone DCT feature points in the DCT feature plane. Secondly, the region of head-shoulder is approximately regarded as combination of the head rectangle and shoulder rectangle, and head rectangle is confirmed by double template matching. Thirdly, Canny operator and morphological operation are applied to the region of head-shoulder in feature plane to get the object mask and the region of object mask is rectified by correlation of DCT blocks to get high-quality segmentation.展开更多
目的：分析比较手膝俯卧位分娩与平卧位分娩在采用等待娩肩的措施时对母婴结局的影响。方法共有621例产妇进入临床研究，其中手膝卧位组364例，平卧位组257例，两组均采用等待至少1次宫缩娩肩助产方式。比较两组的肩难产发生率、产程时...目的：分析比较手膝俯卧位分娩与平卧位分娩在采用等待娩肩的措施时对母婴结局的影响。方法共有621例产妇进入临床研究，其中手膝卧位组364例，平卧位组257例，两组均采用等待至少1次宫缩娩肩助产方式。比较两组的肩难产发生率、产程时间、产后出血、新生儿评分、头-肩时间等指标。结果产妇分娩的头-肩时间为5～480 s，平均（53.6±40.1）s；头-肩时间≤60 s 与＞60s 比较，新生儿窒息率差异无统计学差异，头-肩时间≤120 s 与＞120 s 比较，新生儿窒息率增高，差异有统计学意义。手膝俯卧位组与平卧位组的头-肩时间分别为（60.1±46.8）s 和（44.5±25.6）s，差异有统计学意义。手膝俯卧位与平卧位的肩难产发生率分别为0，1.6％，差异有统计学意义。新生儿窒息的发生率分别为1.4％，1.9％，两组差异无统计学意义。结论采用手膝俯卧位分娩和等待至少一次宫缩自然娩肩，减少肩难产发生率，不增加新生儿窒息率，是安全可行的助产方法。展开更多
针对视频中的行人检测问题,提出了LW-PGD(locating windows based on the pixel gradient direction of the top of head)快速定位头肩部和基于融合特征检测的方法。首先利用头顶像素点的梯度方向具有固定范围这一特性在前景中找出头顶...针对视频中的行人检测问题,提出了LW-PGD(locating windows based on the pixel gradient direction of the top of head)快速定位头肩部和基于融合特征检测的方法。首先利用头顶像素点的梯度方向具有固定范围这一特性在前景中找出头顶候选点,根据该点快速确定人体头肩部区域,将其作为待测窗口;然后提取待测窗口的方向梯度直方图(histogram of oriented gradient,HOG)特征和HSV(hue saturation value)颜色特征;最后采用支持向量机(support vector machine,SVM)训练得到人体头肩部的分类器。实验表明,与传统的滑动窗口搜索方法相比,根据头顶点可以快速选取含有人体头肩部的待测窗口,提高了检测的效率;HOG和HSV多特征融合提高了检测的精确性,从而提出的算法有助于后续的行人分析。展开更多
基金Supported by the National 973 Project of China (No.2001CB309403).
文摘More attention has been paid to the study of video object segmentation in compressed domain these years, which has already led to some practical technology. In this paper, a scheme is put forward for segmentation of head-shoulder video in MPEG (Motion Picture Experts Group) compressed domain. The conception of DCT (Discrete Cosine Transform) feature plane is defined. In the suggested scheme, firstly, the face region is detected by clustering skin-tone DCT feature points in the DCT feature plane. Secondly, the region of head-shoulder is approximately regarded as combination of the head rectangle and shoulder rectangle, and head rectangle is confirmed by double template matching. Thirdly, Canny operator and morphological operation are applied to the region of head-shoulder in feature plane to get the object mask and the region of object mask is rectified by correlation of DCT blocks to get high-quality segmentation.
文摘目的：分析比较手膝俯卧位分娩与平卧位分娩在采用等待娩肩的措施时对母婴结局的影响。方法共有621例产妇进入临床研究，其中手膝卧位组364例，平卧位组257例，两组均采用等待至少1次宫缩娩肩助产方式。比较两组的肩难产发生率、产程时间、产后出血、新生儿评分、头-肩时间等指标。结果产妇分娩的头-肩时间为5～480 s，平均（53.6±40.1）s；头-肩时间≤60 s 与＞60s 比较，新生儿窒息率差异无统计学差异，头-肩时间≤120 s 与＞120 s 比较，新生儿窒息率增高，差异有统计学意义。手膝俯卧位组与平卧位组的头-肩时间分别为（60.1±46.8）s 和（44.5±25.6）s，差异有统计学意义。手膝俯卧位与平卧位的肩难产发生率分别为0，1.6％，差异有统计学意义。新生儿窒息的发生率分别为1.4％，1.9％，两组差异无统计学意义。结论采用手膝俯卧位分娩和等待至少一次宫缩自然娩肩，减少肩难产发生率，不增加新生儿窒息率，是安全可行的助产方法。
文摘针对视频中的行人检测问题,提出了LW-PGD(locating windows based on the pixel gradient direction of the top of head)快速定位头肩部和基于融合特征检测的方法。首先利用头顶像素点的梯度方向具有固定范围这一特性在前景中找出头顶候选点,根据该点快速确定人体头肩部区域,将其作为待测窗口;然后提取待测窗口的方向梯度直方图(histogram of oriented gradient,HOG)特征和HSV(hue saturation value)颜色特征;最后采用支持向量机(support vector machine,SVM)训练得到人体头肩部的分类器。实验表明,与传统的滑动窗口搜索方法相比,根据头顶点可以快速选取含有人体头肩部的待测窗口,提高了检测的效率;HOG和HSV多特征融合提高了检测的精确性,从而提出的算法有助于后续的行人分析。
