METHODS AND SYSTEMS FOR CONDITIONING PHYSIOLOGICAL INFORMATION BASED ON A SORTED DIFFERENCE SIGNAL
A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate a difference signal based on the physiological signal and sort the difference signal. The system may identify values in the sorted difference signal that exceed a threshold, and modify the physiological signal based on the identified values. The modification may include reducing, or otherwise limiting, some differences between adjacent values in the physiological signal.
1 . A subject monitoring system for conditioning a physiological intensity signal, comprising:
a sensor configured to generate a physiological signal, wherein the sensor detects light attenuated by a subject; and
processing equipment coupled to the sensor, wherein the processing equipment is configured to:
generate a difference signal based on the physiological signal;
sort the difference signal to generate a sorted difference signal;
identify one or more points in the sorted difference signal that exceed a threshold; and
generate a modified physiological signal based on the one or more points.
2 . The system of claim 1 , wherein the processing equipment is further configured to determine the threshold based on the sorted difference signal.
3 . The system of claim 1 , wherein the processing equipment is further configured to:
determine a line fit based on the sorted difference signal; and
determine the threshold based on the line fit.
4 . The system of claim 1 , wherein the processing equipment is further configured to:
modify the one or more points in the sorted difference signal to generate a modified sorted difference signal; and
generate the modified physiological signal by:
reordering the modified sorted difference signal to generate a reordered signal; and
integrating the reordered signal.
5 . The system of claim 1 , wherein the processing equipment is further configured to modify the one or more points in the sorted difference signal to be equal to the threshold.
6 . The system of claim 1 , wherein the physiological signal is a photoplethysmograph signal and wherein the processing equipment is further configured to determine a physiological rate of the subject based on the modified physiological signal.
7 . A processing module for conditioning a physiological intensity signal, wherein the processing module is configured to:
receive a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;
generate a difference signal based on the physiological signal;
sort the difference signal to generate a sorted difference signal;
identify one or more points in the sorted difference signal that exceed a threshold; and
generate a modified physiological signal based on the one or more points.
8 . The processing module of claim 7 , further configured to determine the threshold based on the sorted difference signal.
9 . The processing module of claim 7 , further configured to:
determine a line fit based on the sorted difference signal; and
determine the threshold based on the line fit.
10 . The processing module of claim 7 , further configured to:
modify the one or more points in the sorted difference signal to generate a modified sorted difference signal; and
generate the modified physiological signal by:
reordering the modified sorted difference signal to generate a reordered signal; and
integrating the reordered signal.
11 . The processing module of claim 7 , further configured to modify the one or more points in the sorted difference signal to be equal to the threshold.
12 . The processing module of claim 7 , wherein the physiological signal is a photoplethysmograph signal, the processing module further configured to determine a physiological rate of the subject based on the modified physiological signal.
13 . A method for conditioning a physiological intensity signal, comprising:
receiving, using processing equipment, a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;
generating, using the processing equipment, a difference signal based on the physiological signal;
sorting, using the processing equipment, the difference signal to generate a sorted difference signal;
identifying, using the processing equipment, one or more points in the sorted difference signal that exceed a threshold; and
generating, using the processing equipment, a modified physiological signal based on the one or more points.
14 . The method of claim 13 , further comprising determining the threshold based on the sorted difference signal.
15 . The method of claim 13 , further comprising:
determining a line fit based on the sorted difference signal; and
determining the threshold based on the line fit.
16 . The method of claim 13 , further comprising modifying the one or more points in the sorted difference signal to generate a modified sorted difference signal, wherein generating the modified physiological signal comprises:
reordering the modified sorted difference signal to generate a reordered signal; and
integrating the reordered signal.
17 . The method of claim 13 , further comprising modifying the one or more points in the sorted difference signal to be equal to the threshold.
18 . The method of claim 13 , wherein the physiological signal is a photoplethysmograph signal, the method further comprising determining a physiological rate of the subject based on the modified physiological signal.
19 . A computer-readable medium for use in conditioning a physiological intensity signal, the computer-readable medium having computer program instructions recorded thereon for:
receiving a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;
generating a difference signal based on the physiological signal;
sorting the difference signal to generate a sorted difference signal;
identifying one or more points in the sorted difference signal that exceed a threshold; and
generating a modified physiological signal based on the one or more points.
20 . The computer-readable medium of claim 19 , having further computer program instructions recorded thereon for determining the threshold based on the sorted difference signal.
21 . The computer-readable medium of claim 19 , having further computer program instructions recorded thereon for:
determining a line fit based on the sorted difference signal; and
determining the threshold based on the line fit.
22 . The computer-readable medium of claim 19 , having further computer program instructions recorded thereon for:
modifying the one or more points in the sorted difference signal to generate a modified sorted difference signal;
generating the modified physiological signal by:
reordering the modified sorted difference signal to generate a reordered signal; and
integrating the reordered signal.
23 . The computer-readable medium of claim 19 , having further computer program instructions recorded thereon for modifying the one or more points in the sorted difference signal to be equal to the threshold.
24 . The computer-readable medium of claim 19 , wherein the physiological signal is a photoplethysmograph signal, the computer-readable medium having further computer program instructions recorded thereon for determining a physiological rate of the subject based on the modified physiological signal.