Patent ID: 9042973
Filing Date: 2015-05-26
Classification: A61B

Abstract:
1. An apparatus for determining a signal quality of an input signal representing a repetitious phenomena derived from at least one sensor connected to a patient comprising: a detector that receives the input signal and determines data representing the repetitious phenomena from the input signal for use in determining at least one patient parameter; a measurement processor electrically coupled to the detector that determines a first signal quality value by identifying at least one feature of the repetitious phenomena data and compares the at least one feature of a first set of the determined repetitious phenomena data with the at least one feature of a second set of the determined repetitious phenomena data to determine a feature variability value and using the feature variability value to determine a stability value representative of the quality of the input signal, wherein said measurement processor measures a second signal quality value associated with the input signal, the second signal quality value being measured prior to the input signal being processed by the detector, the second signal quality value is determined by evaluating a randomness of a finite sequence of data samples included in the input signal to determine a complexity value associated with the input signal and comparing the complexity value with a threshold to determine an amount of noise in the input signal, and said measurement processor evaluates the randomness of the input signal by converting the input signal into a binary signal, sequentially scanning the binary signal, incrementing a complexity counter by one upon detecting a change in a subsequence of consecutive characters in the binary signal and comparing a value of complexity counter with a threshold to determine the complexity value associated with the input signal.