Patent ID: 8858454

Claim:
A pulse rate sensor for measuring a physiological parameter of an individual comprising: an optical emitter for transmitting light from a light source into body tissue; a photo detector for receiving reflected light from said body tissue and producing a pulse signal indicative of reflected light; an accelerometer for measuring regular motion of the individual and producing an accelerometer output signal indicative of the regular motion; a piezo sensor for measuring erratic motion of the user and producing a contact type motion sensor output signal indicative of the erratic motion; and a microprocessor for receiving the pulse signal, the accelerometer output signal, and the piezo sensor output signal, and determining the pulse rate of the individual, wherein the pulse rate is determined by: conditioning the pulse signal wherein conditioning comprises: sampling and filtering said pulse signals with a non-adaptive low-pass filter to produce filtered signals; applying direct current compensation to said filtered signals; discriminating motion based on said direct current compensation signal; and if no motion is detected, applying peak detection algorithms to calculate said pulse rate, else applying frequency analysis algorithms to calculate said pulse rate wherein said peak detection algorithms comprise: taking a first derivative over said filtered signal; computing a second derivative from said first derivative; finding peaks within said filtered signal using said first and second derivatives; and calculating instantaneous pulse rate as the difference between peaks in said filtered signal; and removing portions of the conditioned pulse signal caused by regular motion and erratic motion of the individual.