2020 journal article

Automated High-Frequency Observations of Physical Activity Using Computer Vision

MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 52(9), 2029–2036.

author keywords: DIRECT OBSERVATION; BUILT ENVIRONMENT; PARK; SCHOOL; VIDEO
MeSH headings : Accelerometry; Algorithms; Built Environment; Computers; Exercise; Humans; Observation / methods; Parks, Recreational; Schools; Video Recording
TL;DR: Computer vision algorithms are promising for automated assessment of setting-based physical activity that would require less manpower than human observation, produce more and potentially more accurate data, and allow for ongoing monitoring and feedback to inform interventions. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: September 14, 2020

ABSTRACT Purpose To test the validity of the Ecological Video Identification of Physical Activity (EVIP) computer vision algorithms for automated video-based ecological assessment of physical activity in settings such as parks and schoolyards. Methods Twenty-seven hours of video were collected from stationary overhead video cameras across 22 visits in nine sites capturing organized activities. Each person in the setting wore an accelerometer, and each second was classified as moderate-to-vigorous physical activity or sedentary/light activity. Data with 57,987 s were used to train and test computer vision algorithms for estimating the total number of people in the video and number of people active (in moderate-to-vigorous physical activity) each second. In the testing data set (38,658 s), video-based System for Observing Play and Recreation in Communities (SOPARC) observations were conducted every 5 min (130 observations). Concordance correlation coefficients (CCC) and mean absolute errors (MAE) assessed agreement between (1) EVIP and ground truth (people counts+accelerometry) and (2) SOPARC observation and ground truth. Site and scene-level correlates of error were investigated. Results Agreement between EVIP and ground truth was high for number of people in the scene (CCC = 0.88; MAE = 2.70) and moderate for number of people active (CCC = 0.55; MAE = 2.57). The EVIP error was uncorrelated with camera placement, presence of obstructions or shadows, and setting type. For both number in scene and number active, EVIP outperformed SOPARC observations in estimating ground truth values (CCC were larger by 0.11–0.12 and MAE smaller by 41%–48%). Conclusions Computer vision algorithms are promising for automated assessment of setting-based physical activity. Such tools would require less manpower than human observation, produce more and potentially more accurate data, and allow for ongoing monitoring and feedback to inform interventions.