The Study Of Motion Artifacts On LCD

With the development of LCD's technology and industry, LCD plays an important role in the Display area. As LCD's final fault, motion artifacts blocks LCD's application on TV. It is urgent to develop a way to study and characterize the motion artifacts of LCD.At present, several evaluation and measurement methods have been proposed to evaluate the motion artifacts. The LC response time (LCRT) is normally used to characterize the temporal performances of LCD, but LCRT can not explain all reasons causing by motion artifacts,As a matter of fact, it is more like the beginning of the study. Based on the LCD hold-type display characteristics and the principle of smooth-pursuit eye-tracking, two alternatives are proposed. One is direct measurement system, in which high speed CCD camera, rotation camera or rotation mirror with static camera is used to simulate the eye's motion. But camera based systems need precise mechanism and complex triggering so these system are expensive and complex. In addition, the measured result taken by CCD camera is still some different to the actually perceived moving image. Another method is simulation system which is based on transition curves and model of smooth-pursuit eye-tracking. Simulation method is flexible, less expensive and simple mechanism. By capturing the transition curve, we can not only evaluate motion artifacts, but also realize the light behavior which can help us improve the design. So we selected the simulation way with measurement of transition curves and model of smooth-pursuit eye-tracking to set up evaluation system by means of the state-of-the-art software and hardware.The hardware includes programmable image generation board and response curve measurement circuit. First, the board generates different grayscales test pattern on tested LCD as requirement. Second, visual corrected photodiode is used to capture the luminance transition change on LCD. Third, the output from photodiode is amplified by amplification circuit. At last, the signal is captured by A/D conversion and collection card as the response curve.The software that is the author's main tasks is based on virtual instrument software—LabVIEW version 7.1 which has an advantage of data processing, friendly interface, convenient transferring and controlling, storing etc, Comparing the traditional equipment, The function of the virtual measurement instrument can be realized and extended easily. The control program is the human and machine mutual interface in experiment and it has three interfaces.The captured interface sets the parameters and controls the image generation board real-time and triggers the DAQ card to capture response curve harmoniously. The collection process is controlled accurately so that we can get the response curve continuously and synchronously between different gray levels as requirements.The processing interface reduces noise containing in the transition curve, program makes use of multi-add-average-arithmetic to improve transition curves'SNR. The integrally periodic waveform response curve which is important factor to analyze is saved at the same time. The response waveform and some analyzing results, such as response time, are shown on the interface and can be selected to save.The simulation interface generates simulated blurred image by taking into account the properties of visual system and transition curve and demonstrates the still simulated blurred image on the same LCD to compare perceived effect with the actual moving image. It is validate the...