建立信息隐藏技术的评价标准十分必要。隐写术的视觉不可感知性是评价隐写术性能的重要指标之一。基于HVS模型，给出不可感知性评价指标CHD。实验结果表明，CHD的判定结果反映了人类视觉的亮度，对比度和色彩掩蔽特性，可以作为隐写术的不可感知性评价指标。

It is necessary to establish a benchmark for information hiding. Imperceptibility is an important index to evaluate the performance of steganography. Based on HVS model，a new imperceptibility measure CHD for color stego image was proposed．Experimental results show that the quality of stego image calculated by CHD reflects the luminance masking, texture masking and color masking of HVS，and CHD can be used to evaluate the imperceptibility of steganography tools．