Respiratory diseases in children under the age of two, such as
bronchiolitis or pneumonia, are a major cause of emergency consultations
in hospital and primary care settings, being also a significant cause of
mortality in low-income countries. Early detection of respiratory
distress and high respiratory rate is crucial for timely intervention
and improved clinical outcomes. In this study, we developed and
evaluated two computer vision techniques for respiratory rate estimation
in young children. The first technique, remote photoplethysmography,
uses changes in skin color due to blood flow modulation to estimate the
respiratory rate, while the second technique, designed in this work,
uses the motion of a sticker placed on the patient's abdomen, and
captures the variations of the reflected light throughout inhalation and
exhalation. Both techniques were tested on a dataset of video recordings
of children under the age of two taken in the Hospital 12 de Octubre of
Madrid. Our results show that both techniques achieved accurate
respiratory rate estimation, being the second technique the one with
lower mean absolute error. For high respiratory frequencies, the values
of the estimator are less than 3 bpm. These techniques have the
potential to be used as low-cost and non-invasive tools for respiratory
rate monitoring in low-resource settings, including remote and
underserved areas of Africa. Besides, the elaboration of a labeled
dataset will serve as potential groundwork for further research in this
matter.