Fig. 1.

Automated finger fold recognition to monitor RA. Hand photographs are taken by a smartphone in a standardized manner (a). Hands, and subsequently PIP joints, are automatically recognized and extracted. Finger fold lines are isolated from the images, measured and related to the joint diameter (b, c). A convolutional deep neural network was used to train a model for classification of extracted finger fold patterns into swollen versus non swollen joints (d) A heatmap of the cropped PIP joints confirmed finger folds as the region of interest for correct classification (e).