Table 3 Equations and descriptions of peak features

Amplitudes

Peak-to-peak amplitude of the first half wave

\(f_{1} = \left| {x\left( {PP_{i} } \right) - x\left( {VP1_{i} } \right)} \right|\)

Amplitude between the magnitude of peak and the magnitude of valley at the first half wave

Peak-to-peak amplitude of the second half wave

\(f_{2} = \left| {x\left( {PP_{i} } \right) - x\left( {VP2_{i} } \right)} \right|\)

Amplitude between the magnitude of peak and the magnitude of valley of the second half wave

Turning point amplitude of the first half wave

\(f_{3} = \left| {x\left( {PP_{i} } \right) - x\left( {TP1_{i} } \right)} \right|\)

Amplitude between the magnitude of peak and the magnitude of turning point at the first half wave

Turning point amplitude at the second half wave

\(f_{4} = \left| {x\left( {PP_{i} } \right) - x\left( {TP2_{i} } \right)} \right|\)

Amplitude between the magnitude of peak and the magnitude of turning point at the second half wave

Moving average amplitude

\(f_{5} = \left| {x\left( {PP_{i} } \right) - MAC\left( {PP_{i} } \right)} \right|\)

Amplitude between the magnitude of peak and the magnitude of moving average

Widths

Peak width

\(f_{6} = \left| {VP1_{i} - VP2_{i} } \right|\)

Width between valley point of first half point and valley point at second half wave

First half wave width

\(f_{7} = \left| {PP_{i} - VP1_{i} } \right|\)

Width between peak point and valley point at first half wave

Second half wave width

\(f_{8} = \left| {PP_{i} - VP2_{i} } \right|\)

Width between peak point and valley point of second half wave

Turning point width

\(f_{9} = \left| {TP1_{i} - TP2_{i} } \right|\)

Width between turning point at first half wave and turning point at the second half wave

First half wave turning point width

\(f_{10} = \left| {PP_{i} - TP1_{i} } \right|\)

Width between turning point at first half wave and peak point

Second half wave Turning point width

\(f_{11} = \left| {PP_{i} - TP2_{i} } \right|\)

Width between turning point at second half wave and peak point

FWHM

\(f_{12} = \left| {HP1_{i} - HP2_{i} } \right|\)

Width between half point of first half wave and half point of second half wave

Slopes

Peak slope at the first half wave

\(f_{13} = \left| {\frac{{x\left( {PP_{i} } \right) - x\left( {VP1_{i} } \right)}}{{PP_{i} - VP1_{i} }}} \right|\)

Slope between a peak point and valley point at the first half wave

Peak slope at the second half wave

\(f_{14} = \left| {\frac{{x\left( {PP_{i} } \right) - x\left( {VP2_{i} } \right)}}{{PP_{i} - VP2_{i} }}} \right|\)

Slope between a peak point and valley point at the second half wave

Turning point slope at the first half wave

\(f_{15} = \left| {\frac{{x\left( {PP_{i} } \right) - x\left( {TP1_{i} } \right)}}{{PP_{i} - TP1_{i} }}} \right|\)

The slope between peak point and turning point at the first half wave

Turning point slope at the second half wave

\(f_{16} = \left| {\frac{{x\left( {PP_{i} } \right) - x\left( {TP2_{i} } \right)}}{{PP_{i} - TP2_{i} }}} \right|\)

The slope between peak point and turning point at the second half wave