一种基于人眼视觉特性的ROI渐进图像传输算法

一般基于ROI的渐进传输算法都未充分考虑人眼视觉特性，利用小波变换的特点并结合人眼视觉的掩蔽效应，提出了一种改进的ROI渐进图像传输算法。首先传输图像的低分辨率形式，供用户选择是否继续传输图像。进行ROI图像传输时，在不影响ROI主观质量的前提下，可以对ROI视觉效果影响不明显的小波系数延后传输，而利用节省下的带宽传输视觉上重要的背景系数。此外，还可以根据网络带宽情况设置扩展因子，控制背景图像进行分级扩展传输，从而保证接收到的图像始终具有较好的整体视觉效果。仿真实验证明了该算法的有效性及扩展因子的控制作用。

ROI progressive image transmission algorithm based on human visual specialties

In conventional region of interest(ROI) progressive image transmission algorithms,human visual specialties are not taken into account.An improved algorithm based on the properties of wavelet transform and human visual specialties was proposed.Firstly,an image with low resolution was transmitted so that user could decide if the image was needed.On the condition that there is no impact on the subjective quality of ROI,the transmission of ROI coefficients which are not important for visual quality could be delayed.And the bandwidth could be utilized to transmit the important back ground(BG) coefficients.Furthermore,depending on the bit rates,an expansion factor was evaluated.To guarantee the image with better visual effects,the transmission of BG image was controlled by the expansion factor.The experimental results show that the improved algorithm is effective and the expansion factor can accommodate image transmission.