Frequency Domain Study for Motion Blur Improvement on LCDs Dynamic Backlight

Based on the model of Human visual system, the temporal step response curve measured from a LCD, and the theory of modulation transfer function, the validation of dynamic backlight method for improving LCDs motion blur was discussed from the view of frequency domain. The relations between the backlight blinking parameters and dynamic MTF characteristics of LCDs were simulated and analyzed at the certain moving speed. MTF(v) was specially defined as one of the index for perceived image quality assessment to reflect the relation between MTF characteristics and the image moving velocity.The results indicated that dynamic MTF(f) of LCDs has a low pass characteristics presented by Sinc function formula,and the value of dynamic MTF at high frequency components decreases with the increase of the image moving velocity, so that the resolution of the image displayed on LCDs is degraded. The proper choice of the blinking parameters, such as cycle numbers per frame, duty cycle and temporal period in a blinking cycle, were discussed, in order to increase the bandwidth, the MTF at high frequency components or the area of the MTF(f) curve to decrease of motion blur and improve the image resolution. The MTF(v) curve specially defined for denoting the relationship between motion blur and image velocity has the same characteristics.