Experimental Study of Radial Distortion Compensation for Camera Submerged Underwater Using Open SaltWaterDistortion Data Set

Abstract

This paper describes a new open data set, consisting of images of a chessboard collected underwater with different refractive indices, which allows for investigation of the quality of different radial distortion correction methods. The refractive index is regulated by the degree of salinity of the water. The collected data set consists of 662 images, and the chessboard cell corners are manually marked for each image (for a total of 35,748 nodes). Two different mobile phone cameras were used for the shooting: telephoto and wide-angle. With the help of the collected data set, the practical applicability of the formula for correction of the radial distortion that occurs when the camera is submerged underwater was investigated. Our experiments show that the radial distortion correction formula makes it possible to correct images with high precision, comparable to the precision of classical calibration algorithms. We also show that this correction method is resistant to small inaccuracies in the indication of the refractive index of water. The data set, as well as the accompanying code, are publicly available.

Prediction of Cable Behavior Using Finite Element Analysis Results for Flexible Cables

“…The marker center coordinates were calculated by calculating the rotation speed of the cylinder and the number of frames of the high-speed camera. At this time, the distance from the center of the actual camera to the object changes due to the distortion of the camera lens, so the exact distance was corrected [19,20]. To accurately detect the position of the yellow marker attached to the cable, we used a specific color algorithm in OpenCV to detect its color [21][22][23].…”