Table 1 Elements of the feature vector

1

1st raw time moment of spectrogram

2

2nd raw time moment of spectrogram

3

3th raw time moment of spectrogram

4

4th raw time moment of spectrogram

5

5th raw time moment of spectrogram

6

1st raw frequency moment of spectrogram

7

2nd raw frequency moment of spectrogram

8

3th raw frequency moment of spectrogram

9

4th raw frequency moment of spectrogram

10

5th raw frequency moment of spectrogram

11

Normalized number of blobs

12

Mean time–frequency size of blobs

13

Minimum time–frequency size of blobs

14

Maximum time–frequency size of blobs

15

Standard deviation of blobs’ time–frequency size

16

Mean time duration of blobs

17

Minimum time duration of blobs

18

Maximum time duration of blobs

19

Standard deviation of blobs’ time duration

20

Mean frequency band of blobs

21

Minimum frequency band of blobs

22

Maximum frequency band of blobs

23

Standard deviation of blobs’ frequency band

24

Number of blobs in the 1st sector

25

Number of blobs in the 2nd sector

26

Number of blobs in the 3th sector

27

Number of blobs in the 4th sector

28

Number of blobs in the 5th sector

29

Number of blobs in the 6th sector

30

Number of blobs in the 7th sector

31

Number of blobs in the 8th sector

32

Number of blobs in the 9th sector