Identification of bitmap compression history: JPEG detection and quantizer estimation
Identification of bitmap compression history: JPEG detection and quantizer estimation
复制标题
DOI：
10.1109/tip.2002.807361
复制
发表时间：
2003-02
期刊：
影响因子：
--
通讯作者：
Z. Fan;R. Queiroz
中科院分区：
文献类型：
--
作者：
Z. Fan;R. Queiroz
有时，图像处理单元仅继承光栅位图格式的图像，使得在不知道可能损害图像质量的过去操作（例如，压缩）。为了进行进一步的处理，不仅要知道图像之前是否经过JPEG压缩，而且要了解使用了什么量化表。例如，如果想要移除JPEG伪像或用于JPEG重新压缩，则是这种情况。本文提出了一种快速有效的方法来判断图像是否经过JPEG压缩。在检测到压缩签名之后，我们估计压缩参数。具体来说，我们开发了一种方法的JPEG量化步骤的最大似然估计。量化器估计方法是非常鲁棒的，使得估计的量化器步长仅偶尔偏离，并且当偏离时，偏离一个值。
Sometimes image processing units inherit images in raster bitmap format only, so that processing is to be carried without knowledge of past operations that may compromise image quality (e.g., compression). To carry further processing, it is useful to not only know whether the image has been previously JPEG compressed, but to learn what quantization table was used. This is the case, for example, if one wants to remove JPEG artifacts or for JPEG re-compression. In this paper, a fast and efficient method is provided to determine whether an image has been previously JPEG compressed. After detecting a compression signature, we estimate compression parameters. Specifically, we developed a method for the maximum likelihood estimation of JPEG quantization steps. The quantizer estimation method is very robust so that only sporadically an estimated quantizer step size is off, and when so, it is by one value.