Page 371 - Practical Design Ships and Floating Structures

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the recorded past damages which is useful for the surveyor.
(3) Efficient recording of the result of the inspection such as detected damages or measured plate
thickness and efficient input of the result of the inspection into the information database of damages.

Fig.l(b) and Fig.S(a) shows the concept of the proposed ship inspection supporting system. As shown
in Fig.l(b), the concept is based on the information system of damages of ship structures described in
the previous section. In the process with the inspection supporting system, the information such as the
ship hull structures and past recorded damages is transferred from the information system to the
inspection supporting system just before the inspection starts (Fig. 1 (1)(2)). When the surveyor enters
into the target tank with the equipments shown in Fig.S(a), 3D computer graphics of the ship structure
is displayed in the HMD. By utilizing the display of the ship structure, appropriate instructions by the
electronic manual and accurate display of the information about past damages may be possible. When
the damage is detected or the plate thickness is measured, the result of the inspection is not recorded in
the traditional memo pad but directly recorded in the inspection supporting system (Fig.l(3)). Since the
surveyor equips a Virtual Reality (VR) sensor which senses the position of the surveyor in real-time,
the display of the 3D graphical model in Head Mount Display (HMD) can match to his actual view
even if the inspector moves and the direction of his head changes in the tank. This helps the surveyor to
recognize the location of the detected damages even in the complicated hull structure of the ship. After
the inspection is finished, the collected data such as the damage information is send back to the
information system of damages of ship structures (Fig.l(4)), so that immediate evaluation of the
damages is possible(Fig.l(5)). In the inspection process, it is sometimes not so easy to use an input
device such as the mouse for computers because the environment of the inspection is usually not so
good (dark and with precarious foothold). For this reason, we proposed the utilization of a voice input
system (FigS(a)-(3)) by which the surveyor can activate the computer command and input the detected
damages to the inspection supporting system.

(4) VR Sensor -+A
HMD VR Sensor
(3) Voice Input System

(2) Input Device I 1 C& >utcr
nnablc (Wcarablc)

Microphone for ViaVoice
HMD: I-Glasses by io Display Systems LE.
(Translucent)
Information System for 1 VR-Sensor: GU-3011 by Datatec Co. Ltd.
(Triaxial angle and acceleration detection)
Damages of Ship Structures Input Device: Spaceball
(Input of 6 degrees of freedom)
(a) Concept (b) Prototype system
Figure 5: Inspection style with the proposed ship inspection supporting system

4.2 The Prototype System

Based on the above concept, a prototype system is constructed as shown in Fig.S(b). HMD, VR-sensor
and the input device are connected to a portable computer and integrated by using the software
developed by the authors. For the development of the software, Visual C++ and WorldToolKit by
SENSES Co.Ltd. which is a toolkit for virtual reality applications are used. For the development of the
voice input system, a microphone and the speech recognition software, ViaVoice, with its toolkit for
developers by IBM are used.