针对最不重要比特位(least significant bit, LSB)替换隐写算法，将加权载密图像(weighed-stego, WS)残差法和最大后验概率(maximum a posteriori, MAP)载体估计法相结合，提出了一种改进的载体估计方法. 首先利用WS方法初步定位负载，然后将该初步定位结果作为先验信息应用到改进的MAP载体估计算法中，可以
得到更精确的载体估计算法，最后计算残差得到最终的负载定位结果. 实验表明，无论是针对空域BMP图像还是JPEG解压缩图像上的LSB替换隐写，该方法均能提高负载定位的准确率，且对于不同嵌入率也有较好的稳健性.
This paper proposes a modified method of payload location aimed at least significant bit replacement (LSB-R) by combining weighed-stego (WS) residuals with maximum a posteriori (MAP) cover estimator.We use the WS residuals to locate payloads, and take the results as a priori information to apply the modified MAP cover estimator to get more accurate cover estimates. The residuals are then computed to locate payloads. Experimental results demonstrate effectiveness of the approach in locating payloads both on JPEGdecompressed images and originally lossless stored images. Furthermore, the proposed approach is suitable for payload location with different embedding rates.
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