Based on the further study on the dynamic dimming algorithms, the Inverse of Mapping Function (IMF) method, the error correction method and the cumulative distribution function (CDF) method are analyzed and applied to get the dimming level in the bottom-lit backlight. 50 typical images are simulated. The power reduction, contrast ratio enhancement, and MSSIM are explored to evaluate the 3 above dimming algorithms, the simulation results show that: IMF method does not apply to the low average luminance images; error correction method is suitable for a wide range of images, but the energy-saving rate is not high; though the energy-saving rate of the CDF method is higher than the other two kinds of algorithms, the image quality has a some kind of distortion.

Multi-block gray statistics local dimming algorithm is proposed to automatically control the brightness of the backlight for reducing energy consumption and enhancing the image quality. The large blocks are used to determine the value of backlight matrix and small blocks are to determine the image block brightness. With the use of BMA (Blur-mask approach) to blur the backlight brightness matrix and compensate LCD control signal, local dimming function is realized.The simulation results show that: for pictures, the average backlight power consumption is decreased markedly by 19.9% and the contrast ratio is increased by 53%.