Signal processing for media type identification

Abstract

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.

Dependencies are inferred from the claim text.