Figure 4.
A photograph presents a vertically mounted rectangular block covered with a checker pattern. A rectangular bounding outline surrounds the block, and a labelled arrow points to the annotation area with the text Labeling location. A coordinate marker labelled open bracket x comma y close bracket is positioned near the centre of the block. Vertical and horizontal double-headed arrows indicate the block dimensions labelled h and b respectively. The block is mounted on a base beneath a sensor assembly positioned above the structure.One example image for Case2 with M2 labelling and its position