Figure 1: Image processing pipeline.
(A) For each subject’s knee joint, we manually examined all the MRI slices oriented in the sagittal view and selected the slice showing the posterior cruciate ligament (PCL) and indexed it as the center slice (red colored box). The remaining slices were indexed relative to the center slice for each knee. Two-dimensional MRI slices for three different subjects are shown. (B) For each 2D MRI slice of the knee for a subject, we performed linear registration to align the slice with respect to a template that was already selected after manual examination. Later, a region (red colored box) containing the center of the knee joint with dimensions 294×294 pixels was cropped for all registered slices and used for model training. Three cases from the baseline OAI dataset are shown. (C) Sample cases not used for model training due to the presence of various artifacts.