It embeds the watermark bits on the DC of the DCT transform coefficients, for most JPEG quality factor, the method is proved to be robust and effective.

通过对图像做仿jpeg流程的处理，在DCT变换的直流系数上嵌入水印，对于各种常用的JPEG压缩量化因子，可以得到良好的水印嵌入效果。

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The SIGMA DP3 Merrill features a RAW data recording mode for retaining full image capture detail of the utmost quality captured through the direct image sensor, plus a JPEG recording format for convenience.

ENGADGET: Sigma DP3 Merrill packs a Foveon X3 sensor and a fixed F2.8, 75mm-equivalent lens