Fully-Automatic Semantic Segmentation for Food Intake Tracking in Long-Term Care Homes

Malnutrition impacts quality of life and places annually-recurring burden on the health care system. Half of older adults are at risk for malnutrition in long-term care (LTC). Monitoring and measuring nutritional intake is paramount yet involves time-consuming and subjective visual assessment, limiting current methods' reliability. The opportunity for automatic image-based estimation exists. Some progress outside LTC has been made (e.g., calories consumed, food classification), however, these methods have not been implemented in LTC, potentially due to a lack of ability to independently evaluate automatic segmentation methods within the intake estimation pipeline. Here, we propose and evaluate a novel fully-automatic semantic segmentation method for pixel-level classification of food on a plate using a deep convolutional neural network (DCNN). The macroarchitecture of the DCNN is a multi-scale encoder-decoder food network (EDFN) architecture comprising a residual encoder microarchitecture, a pyramid scene parsing decoder microarchitecture, and a specialized per-pixel food/no-food classification layer. The network was trained and validated on the pre-labelled UNIMIB 2016 food dataset (1027 tray images, 73 categories), and tested on our novel LTC plate dataset (390 plate images, 9 categories). Our fully-automatic segmentation method attained similar intersection over union to the semi-automatic graph cuts (91.2% vs. 93.7%). Advantages of our proposed system include: testing on a novel dataset, decoupled error analysis, no user-initiated annotations, with similar segmentation accuracy and enhanced reliability in terms of types of segmentation errors. This may address several short-comings currently limiting utility of automated food intake tracking in time-constrained LTC and hospital settings.