Study On Noise Characteristics And Real Time Filtering Algorithms For Capacitive Touch Panels

The capacitive touch screen is the most widely used and most common touch terminal device at present.According to statistics,more than 90%of smart phones and tablet computers are all capacitive touch panels.For the moment,the domestic touch screen chips are developing rapidly.In nearly ten years of development,many aspects of the touch panel are in the forefront of the world,but the effects of the charger,finger jitter and other noise on the sensitivity of the touch panels can't be avoided.So in order to get a good touch trajectory,a variety of filtering algorithms based on the noise characteristics of capacitive panels are proposed.The following three main aspects of the work were implemented:(1)The construction of touch signal acquisition and processing platform.On the basis of the study of the capacitive touch panels and its driving technology,we choose the 7-inch capacitance panel and the touch panel drive chip of Chipone as the core of the touch signal acquisition platform to locate the touch position with centroid method.And the acquisition and storage of the touch track data is programmed.(2)The analysis of noise characteristics of touch track signal.After processing and displaying the stored signal,we analyze the noise characteristics of the signal,classify the noise,and discuss the sources of all kinds of noise.(3)The design and confirmation of filtering algorithm for touch control trajectory.On the basis of the characteristic analysis of the touch trajectory noise,the noise smoothing algorithm for touch trajectory based on Kalman and particle filter is proposed.The results show that the touch control trajectory smoothing method based on Kalman filter has achieved better trajectory smoothness and faster processing speed.,after test and quantitative analysis of a large number of touch data.After the algorithm and test on the touch control platform,the processing results obtained the recognition of the touch driven integrated circuit design enterprise called Chipone.On the basis of further optimization of the algorithm hardware implementation,the result shows the algorithm can realize the practical application.