为了在降低液晶显示器背光功耗的同时能够保持图像质量，提出了基于分层色调映射的LED背光调制算法。利用低通滤波对图像进行分层，通过亮度对数映射函数把低频部分映射到低动态范围，再与增益后的高频部分相结合为输出图像。将输出图像最大灰阶能够增加的数值作为LED背光因子降低值，采用动态背光缩放技术，降低背光强度值，并提高液晶透光率，对其亮度进行补偿。仿真实验结果表明，采用这种方法，在失真率为4.8%时，可节省功耗15.0%; 在失真率为15.6%时，可节省功耗34.0%。

In order to cut down the power consumption of LCD backlight and maintain the image quality, a modulation algorithm based on hierarchical tone mapping for LED backlight is proposed. The image is layered by the low pass filter, then sent to the brightness logarithmic mapping function to map the low-frequency part to a lower dynamic range, and finally combined with the gained high-frequency part for outputting. Using the numerical value to which the maximum gray-scale of the image can increase as the value of number of the LED backlight factor that can be lowered, dynamic backlight scaling techniques are adopted to reduce the backlight intensity, improve the transmittance of LCD and compensate its brightness. Simulation results show that power consumption is reduced by 15.0% and 34.0% when the distortion rate is at 4.8% and 15.6% respectively.