Ship Hull Vinyl Dataset

An inside sweet water tank at the Institute for Maritime Technology (IMT) in Cape Town was used to take a controlled underwater dataset using a prototype sensor rig - 24 October 2023. The target scene is a life-sized photomosaic of the side of a commercial ship hull that IMT had previously taken when the ship was last in dry dock. The photomosaic is printed onto a large vinyl tarpaulin and hung along the side of the tank. Because the tank platform is 1m from the surface of the water, two 3m PVC pipes were used to manoeuvre the rig through the water, seen below. The rig is moved horizontally along the side of the platform facing the vinyl surface. Marks were placed on the PVC pipes as a visual aid to keep the rig at a relatively constant depth when moving horizontally. Once at the end of the vinyl, the rig is lowered directly downward to the next marked depth and moved horizontally back along the platform, creating a square ‘C’ shape. The data collection starts at 0.5m depth and returns at 1m depth. We provide the data in the form of ROS bags. The data is supplied in two formats: raw and pre-processed. The raw data has not been edited. The pre-processed data has been synchronized and images have been stereo rectified and undistorted. With the ROS bags we also include the stereo camera and stereo-inertial (camera-IMU) calibration output files in yaml format.The original calibration data for camera and stereo-inertial calibrations are also included in ROS bag format so that users can perform their own calibrations if desired. On the sister GitHub, in the Meta Data folder, we detail the data collection method in a PDF for contextual understanding of the dataset and provide the data sheets of the sensors used along with supporting code.

2023年10月24日，开普敦海事技术研究所（Institute for Maritime Technology, IMT）的室内淡水水槽被用于搭载原型传感器装置，采集受控水下数据集。本次实验的目标场景为该研究所此前在某商船最后一次进干船坞时拍摄的全尺寸商用船体舷侧照片镶嵌板：该镶嵌板被打印于大型乙烯基防水布上，并悬挂于水槽侧壁。由于水槽平台距水面高度为1米，研究人员采用两根3米长的聚氯乙烯（PVC）管道操控传感器装置在水中移动，具体布置如下文所述。传感器装置沿平台朝向乙烯基面板的侧壁水平移动；为保证水平移动过程中装置保持相对恒定的深度，研究人员在PVC管道上标注了视觉辅助标记。当装置抵达乙烯基面板末端后，会直接向下下放至下一个标记深度，随后沿平台反向水平移动，由此形成方形‘C’形采集轨迹。本次数据采集始于0.5米深度，返程阶段的深度为1米。本数据集以ROS包（ROS bags）的形式提供，包含原始数据与预处理数据两种格式。其中原始数据未经过任何编辑；预处理数据已完成时间同步，且所有图像均经过立体校正与去畸变处理。随ROS包一同提供的还有yaml格式的双目相机与双目惯性（相机-惯性测量单元（IMU））校准输出文件。此外，本数据集还提供了相机与双目惯性校准的原始校准数据（同样采用ROS包格式），以便用户根据自身需求开展自定义校准工作。在配套GitHub仓库的元数据文件夹中，我们以PDF文档详细说明了数据采集方法，以帮助用户理解该数据集的背景信息，同时一并提供了所用传感器的数据手册与配套代码。