| Summary: | 博士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 98 === The main objective of this thesis is on the development of an image processing-based improved visual guidance scheme with application to an integrated berthing control system (IBCS), which is consisted of two modules; namely the track-keeping control module for the approaching phase and the berthing control module. Comparisons of the performance of two typical shiphandling techniques adopted by the mariners, the nautical instrument navigation scheme and the visual guidance scheme will be made by using a shiphandling simulator. In the traditional visual guidance-based leading line method, two leading marks, arranged in tandem, are used to form a reference track to be followed during the approaching phase. However, this traditional leading line concept only serves for a fixed purpose and the performance degrades if the depth between the leading marks is limited. In the proposed improved visual guidance approach, two canvas targets are arranged along the berthing wall to form a reference base-line, and a virtual leading line perpendicular to the berthing wall is constructed at a position determined by a ratio parameter r, defined as the ratio of the distance between the left-hand target and the virtual leading mark to the distance between the left-hand target and the right-hand target. The position of the virtual leading mark can be adjusted simply by modifying the value of the ratio r. Thus, in contrast to the traditional leading line method, the proposed approach enables multiple leading lines to be constructed using a single set of leading marks. By combining the setting ratio r with the ship to berth distance information, a leading curve during the approaching maneuver stage can be formed, and the proposed improved visual guidance concept can also be used during the berthing phase. During the maneuver trial, the leading marks (i.e. the canvas targets) are captured by a CCD camera mounted on the bridge of the simulator-based ship and the resulting image is processed using a color recognition and noise filtering scheme. The geometric centers of the two leading marks are calculated, and the separation distance between them and the distance from the leading marks to the virtual leading line are used to compute the deviated heading angle and track deviation angle of the boat in accordance with basic trigonometric principles.
In summary, this thesis is devoted to the development of an integrated berthing control system, and the development progress can be divided into four stages which are (a) validation of the proposed New Line of Sight (NLOS) guidance method by using the traditional nautical instrument navigation, and (b) verification of the improved visual guidance scheme in the approaching maneuver, and (c) verification of the improved visual guidance method during the berthing stage, and (d) feasibility study of the improved visual guidance scheme via nautical instrument navigation scheme. The feasibility of the proposed approach will be verified by performing a series of numerical simulation, shiphandling simulation tests and small boat experiments in a real word harbour setting.
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