A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Mosaicking of mountain tunnel images guided by laser rangefinder
Abstract Routine tunnel inspection is important for timely maintaining tunnels and ensuring traffic safety. Owing to the insufficient field of view of one camera, an array of cameras has been employed to acquire multiple tunnel images simultaneously, which are then stitched together to obtain an overall tunnel lining image (TLI) of the complete defects and facilities on the lining surface. However, due to the features inadequacy on the poorly-textured surface, a traditional feature-based mosaicking of multiple images does not work for most tunnel images. Based on the guidance of a laser rangefinder (LRF), this study proposes stitching tunnel images from a geometric perspective involving three steps: extrinsic calibration, coarse mosaicking, and fine mosaicking. Using a checkerboard, the extrinsic parameters of the cameras relative to the LRF are calibrated. The LRF range profile is used to construct a 3D tunnel model, through which a lookup table (LUT) is generated to stitch the tunnel images geometrically, resulting in a coarse TLI. Finally, to reduce misalignments from inaccurate calibration, optional graph cuts are made to optimise the coarse mosaicking if evident features exist in the overlapped areas between images. The proposed technique is tested on actual images collected from the Dingxi tunnel and the Huang Longshan tunnel in China. The experimental results show that the proposed algorithm can obtain the TLI with little geometrical distortion and ensure structural consistency in the features, even if auxiliary facilities are densely distributed on the inner surface of tunnels. The time required for stitching the tunnel images can be improved by 82×, achieving 0.52 s per TLI, if graph cuts are not required.
Highlights A low-cost laser rangefinder is used for modelling a tunnel lining. Tunnel images are stitched from geometrical perspective. Graph cuts optimization can be used to refine the stitching. Extensive experiments demonstrate the excellent performance of the proposed method.
Mosaicking of mountain tunnel images guided by laser rangefinder
Abstract Routine tunnel inspection is important for timely maintaining tunnels and ensuring traffic safety. Owing to the insufficient field of view of one camera, an array of cameras has been employed to acquire multiple tunnel images simultaneously, which are then stitched together to obtain an overall tunnel lining image (TLI) of the complete defects and facilities on the lining surface. However, due to the features inadequacy on the poorly-textured surface, a traditional feature-based mosaicking of multiple images does not work for most tunnel images. Based on the guidance of a laser rangefinder (LRF), this study proposes stitching tunnel images from a geometric perspective involving three steps: extrinsic calibration, coarse mosaicking, and fine mosaicking. Using a checkerboard, the extrinsic parameters of the cameras relative to the LRF are calibrated. The LRF range profile is used to construct a 3D tunnel model, through which a lookup table (LUT) is generated to stitch the tunnel images geometrically, resulting in a coarse TLI. Finally, to reduce misalignments from inaccurate calibration, optional graph cuts are made to optimise the coarse mosaicking if evident features exist in the overlapped areas between images. The proposed technique is tested on actual images collected from the Dingxi tunnel and the Huang Longshan tunnel in China. The experimental results show that the proposed algorithm can obtain the TLI with little geometrical distortion and ensure structural consistency in the features, even if auxiliary facilities are densely distributed on the inner surface of tunnels. The time required for stitching the tunnel images can be improved by 82×, achieving 0.52 s per TLI, if graph cuts are not required.
Highlights A low-cost laser rangefinder is used for modelling a tunnel lining. Tunnel images are stitched from geometrical perspective. Graph cuts optimization can be used to refine the stitching. Extensive experiments demonstrate the excellent performance of the proposed method.
Mosaicking of mountain tunnel images guided by laser rangefinder
Du, Meng (author) / Fan, Jia (author) / Huang, Yuchun (author) / Cao, Min (author)
2021-04-11
Article (Journal)
Electronic Resource
English
Mosaicking of Orthorectified Aerial Images
| Online Contents | 1998
Mosaicking of Orthorectified Aerial Images
| Online Contents | 1998
SEAMLESS MOSAICKING OF ACOUSTIC VIDEO IMAGES
| British Library Online Contents | 2008
Precision Registration and Mosaicking of Multicamera Images
| Online Contents | 2009
A Novel Adjustment Model for Mosaicking Low-Overlap Sweeping Images
| Online Contents | 2017