Abstract:In ferritic stainless steel~FSS!, undesirable surface defects of ridging appear during deep drawing. The formation of these defects is attributed to the inhomogeneous distribution of orientations of individual grains. In the present work, a new electron backscattered diffraction R~a!-value map was introduced, and the dependence of the tensile directions on the formation of ridging in an FSS sheet was discussed using this map. The results showed that large grain colonies in the R~a!-value maps lead to the formation of severe ridging in an FSS sheet.

This study examined the feasibility of using an automatic lens distortion correction (ALDC) camera as the payload for a photogrammetric unmanned aerial vehicle (UAV) system. First, lens distortion for the interior orientation (IO) parameters was estimated. Although previous studies have largely ignored decentering distortion, this study revealed that more than 50% of the distortion of the ALDC camera was caused by decentering distortion. Second, we compared the accuracy of bundle adjustment for camera calibration using three image types: raw imagery without the ALDC option; imagery corrected using lens profiles; and imagery with the ALDC option. The results of image triangulation, the digital terrain model (DTM), and the orthoimage using the IO parameters for the ALDC camera were similar to or slightly better than the results using selfcalibration. These results confirm that the ALDC camera can be used in a photogrammetric UAV system using only self-calibration. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.