In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image d...In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image digest into some wavelet subbands for detecting possible illicit object manipulation undergone in the image. The semi-fragility makes the scheme tolerant against JPEG lossy compression with the quality factor as low as 70%, and locates the tampered area accurately. In addition, the system ensures more security because the embedded watermarks are protected with private keys. The computational complexity is reduced by using parameterized integer wavelet transform. Experimental results show that the proposed scheme guarantees safety of a watermark, recovery of image and localization of tampered area.展开更多
基金This work was supported by the Higher Education Commission of the Government of Pakistan under the Indigenous Ph.D.Scholarship Program(Grant No.17-5-1(Cu-180)HEC/Sch/2004/4343).
文摘In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image digest into some wavelet subbands for detecting possible illicit object manipulation undergone in the image. The semi-fragility makes the scheme tolerant against JPEG lossy compression with the quality factor as low as 70%, and locates the tampered area accurately. In addition, the system ensures more security because the embedded watermarks are protected with private keys. The computational complexity is reduced by using parameterized integer wavelet transform. Experimental results show that the proposed scheme guarantees safety of a watermark, recovery of image and localization of tampered area.
文摘逆时偏移成像建立在全波波动方程基础上,偏移成像结果精准,但偏移时计算耗时长,影响了逆时偏移的实际应用.以缩短逆时偏移的计算时间为目的,分析造成计算耗时的原因,采用基于提升构架的整数小波变换的多级树集合分裂(set partitioning in hierarchical tree,SPIH了)图像编码方法降低逆时偏移计算时的内存占有量,解决了计算耗时过长的问题,提高了综合计算效率.对Marmousi模型叠前深度逆时偏移处理表明,该方法能较好地解决逆时偏移计算耗时的问题,而且不影响成像精度.
