Signal processing for media type identification

摘要

A method for identifying a type of recording medium using a time-varying output signal from a photosensor includes amplifying the time-varying output signal of the photosensor; converting the amplified time-varying output signal of the photosensor to digitized data points using an analog to digital converter thereby creating a first set of digitized data; filtering the first set of digitized data to provide a low pass data set; filtering the first set of digitized data to provide a high pass data set; computing the standard deviation of the low pass data set; computing the standard deviation of the high pass data set; and identifying the recording medium type using values from both the standard deviation of the low pass data set and the standard deviation of the high pass data set.