A qualitative assessment of different sound types of an infant cry

Acoustic characteristics of the cry sound can indicate cry-cause, as it can be perceived easily by humans. Features melody contour, MFCCs and harmonics factors have been explored to identify different sound types of infants cries. But detection of cry-causes is lesser explored. In this paper, different types of infant cries are analyzed from the spectral patterns derived from acoustic signals. Different cry-sound patterns are identified related to different cause-factors of infant cries. A Infant Cry Sounds Database (IIITS-ICSD 2), consisting of infant cry sounds signals for 7 different cry-cause categories, is analyzed. It consists of cry sounds signals categorized for different age-groups of infants. Features F0 and Formants (F1, F2, F3, F4, F5) are used. The F0 is extracted from the cry signal using autocorrelation of the signal, and also by auto-correlation of linear prediction (LP) residual, for validation purpose. The formants are derived using LP spectrum. The cry sounds of infants in the age group of 8 months to 22 months, exhibit remarkably distinct patterns of growing distributed energy with growing age. These spectral patterns are consistent for both male and female infants. In few cry sounds, the pitch variation effects for the Shrill and Growl type sounds are also observed. Whereas in few cry sounds, the Wheezing effect is observed, that has a peculiar effect on the cry melody contour. The formant frequencies of different cry sounds also indicate differences in characteristic patterns. Qualitative assessment of typically different cry sound types is attempted by identifying regions of strained, growling or shrill sound effect onsets, in a cry acoustic signal. This study can help in gaining insight to pathological condition and age of an infant, by acoustic analysis of the cry signal. It can further help towards assisting medical diagnosis, early detection of ailments and timely cure as well.