D R卫星定位算法可以在只观测 3颗卫星的条件下实现用户的三维定位以及授时、授频功能。讨论了利用该算法实现定位的用户接收机的方案。对定位接收机数字处理部分进行了较细致的讨论。对用户进行定位所需的测量量的提取方法作了深入的...D R卫星定位算法可以在只观测 3颗卫星的条件下实现用户的三维定位以及授时、授频功能。讨论了利用该算法实现定位的用户接收机的方案。对定位接收机数字处理部分进行了较细致的讨论。对用户进行定位所需的测量量的提取方法作了深入的分析。提出了D展开更多
With the rapid development of powerful image, editing software makes the forgery of the digital image easy. Researchers proposed methods to cope with image authentication in recent years. We proposed a passive image a...With the rapid development of powerful image, editing software makes the forgery of the digital image easy. Researchers proposed methods to cope with image authentication in recent years. We proposed a passive image authentication technique to determine the copy move forgery that copied a part of an image and pasted it on the other region in the same image. First, the method divides the image into overlapping blocks. It uses LPQ （local phase quantization） to label each block. The column average value of labeled blocks constitutes the feature vector for the block. Similarity among the feature vectors gives a clue about the forgery. Local phase quantization has not been used to detect copy move forgery in the literature before. Experimental results show that, the method has higher accuracy ratios and lower false negative values under blurring operation at high levels compared to other methods. Our method can also detect multiple copy move forgery.展开更多
文摘With the rapid development of powerful image, editing software makes the forgery of the digital image easy. Researchers proposed methods to cope with image authentication in recent years. We proposed a passive image authentication technique to determine the copy move forgery that copied a part of an image and pasted it on the other region in the same image. First, the method divides the image into overlapping blocks. It uses LPQ （local phase quantization） to label each block. The column average value of labeled blocks constitutes the feature vector for the block. Similarity among the feature vectors gives a clue about the forgery. Local phase quantization has not been used to detect copy move forgery in the literature before. Experimental results show that, the method has higher accuracy ratios and lower false negative values under blurring operation at high levels compared to other methods. Our method can also detect multiple copy move forgery.
