Panel and Valve Detection

One of the problems to be addressed in the project is the detection and localisation of an underwater panel. The aim is to have the vehicle perform a valve-turning task autonomously once the location of the panel is known. Detection of the panel is performed by comparing images from the camera with a pre-defined template. A series of images of the panel are taken and the “best” image is selected for use as the template.

Panel template is taken from a close-up image of the panel. A mask is used to highlight the static marks on the panel and ignore the valve handles.

Valve detection is performed by first detecting the panel and making known of the rigid geometry to localise the valves with respect to the centre of the panel. To detect the orientation of the valves, a Hough transform is applied first to detect lines within a bounding box around each valve. The orientation of each valve is then obtained by searching for lines of specified minimum length within the bounding box.

The figures show the detected panel and valves highlighted with white lines at approximate distances 2m and 1m. The detection of valve orientation at large distances can be inaccurate and is only considered at short distances.

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