Development of Software to create a Rectified Image of an Inclined Plane
3. Experiment
We conducted an experiment to investigate performance and user-friendliness of the developed software. The objects of the experiment were four excavation slopes at a dam construction site. Widths of the target slopes range approximately from 10 m to 40m and heights of them range approximately from 5 m to 10m. There were three, three, seven and eight images of the target slopes acquired respectively. Each image covers approximately 7 m wide and 6 m high.
Figure 7 shows a rectified image of one of the target slopes made of a series of three images. Figure 8 shows a rectified image of another target slope made of a series of eight images. There are found some discrepancies between adjacent images in both rectified images. The reason of these discrepancies is that a real target slope is not a plane in the strict sense. Since we assumed that the target slope is a plane with the aim of easy operation, these discrepancies are unavoidable. Fortunately these unavoidable discrepancies are negligible for geological survey at a construction site.
There are found another defect that the outermost images (leftmost image and rightmost image) are slightly distorted. The reason of these distortions is that the outermost images are more weakly constrained than the other inside images. Acquisition of images covering the outside of the target slope lets these distortions avoidable.
Figure 7 Rectified image of a series of three images
Figure 8 Rectified image of a series of eight images
4. Conclusion
We have developed a piece of software to create a rectified image of an inclined plane for geological survey at a construction site. The major advantage of our software is that it is easy for a nonprofessional to create a rectified image with sufficient quality without ground survey of control points. An operator without photogrammetric nor image processing know-how can operate the software easily after brief training, and create a rectified image of the target slope in a short time with requested quality.
Acknowledgements
The authors are grateful to Mr. Masayoshi Kuji, a geological engineer of Technology Research Institute of Maeda Corporation for his help at the experiment of the software.
