Fig. 4.

Example of true object and reconstructed images along with error map and hallucination maps (null space) for OOD data with different reconstruction methods – U-Net (top), PLS-TV (middle) and DIP (bottom). Expanded regions are shown to the right of the reconstructed images. The specific error map (blue) and specific null space hallucinations map (red) are overlaid on the reconstructed images for each method. The image estimated by the U-Net method has some distinct false structures (region within red bounding box) that do not exist in the reconstructed images obtained by using PLS-TV and DIP. This region is also highlighted in the specific null space hallucination map for the U-Net method which suggests that the false structure is a hallucination.