An Evaluation of Two Methodologies for Lens Distortion Removal when EXIF Data is Unavailable

Terpstra, Toby; Miller, Seth; Hashemian, Alireza

doi:10.4271/2017-01-1422

Cited by 11 publications

(2 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 3D to 2D transformation is subject to image distortion: lines that are parallel in the real world are no longer parallel in the image because of perspective distortion, and straight lines of the real world can appear curved in the image because of lens distortion. The latter effect is intrinsic to the used optical device, and can be corrected by using an appropriate camera calibration operation [16,17,18]. The former one is trickier to correct, because it depends on the geometrical configuration of the scene [19].…”

Section: Image Distorsionsmentioning

confidence: 99%

“…As explained before, the image distortion is due to two effects, namely lens (intrinsic) and perspective (extrinsic) distortion. Lens distortion correction requires a fine calibration of the device, using some pictures of a specific target as a chessboard [16,18]. However, such a picture was not available for the camera used to make the contest videos.…”

Section: Perspective Distortion Correctionmentioning

confidence: 99%

See 1 more Smart Citation

Using a smartphone camera to analyse rotating and vibrating systems: Feedback on the SURVISHNO 2019 contest

André

Leclère

Anastasio

et al. 2021

Mechanical Systems and Signal Processing

View full text Add to dashboard Cite

A smartphone is a low-cost pocket wireless multichannel multiphysical data acquisition system: the use of such a device for noise and vibration analysis is a challenging task. To what extent is it possible to carry out relevant analysis from it? The Survishno conference, held in Lyon in July 2019, proposed a contest to participants based on this subject. Two challenges were proposed, wherein each a mute video showing an object moving/excited at different frequencies was provided. Due to the frequencies set and the video sampling characteristics, special effects occurred and are visible on both videos. From the first video, participants were asked to estimate the Instantaneous Angular Speed (IAS) of a rotating fan. From the second video, they were asked to perform the modal analysis of a cantilever beam. This paper gathers the interesting ideas proposed by the contestants and proposes a global method to solve these two problems. One major point of the paper might be the advantageous use of the rolling shutter effect, a well-known artefact of smartphone videos, to perform advanced mechanical analyses: the consideration of the unavoidable slight phase shift between the acquisition of each pixel opens up the possibility to perform a dynamic analysis at frequencies that are much higher than the video frame rate.

show abstract