Fig. 5
Top A crop section of 4 × 5 tiles (enlarged) from a Café Wall of 9 × 14 tiles with 200 × 200 px tiles and 8 px mortar. Bottom left Edge map of the crop section at six scales (\( \sigma_{c} = 8\,\,{\text{to}}\,\,28 \)), with incremental steps of 4 in jet white colour map. Bottom right Detected houghlines displayed in green on the binary edge map and around four reference orientations of horizontal, vertical and diagonals. Blue lines indicate the longest detected lines at each scale of the edge map (Reproduced by permission from [145]). (Color figure online)