The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The sonar images can be applied for underwater visual inspection using autonomous underwater vehicle (AUV) that requires underwater object recognition. However, the high noise and low resolution of sonar images are obstacles of object recognition. In this paper, we review a sonar image simulator-based underwater object recognition algorithm for forward-looking imaging sonar. Then, we verify the feasibility...
The forward-looking imaging sonar is a prospective solution for underwater visual surveying because it allows long-range visibility in turbid water, and provides a high frame rate. However, the acoustic images are degraded by speckle noise. In this paper, we propose an algorithm to reduce the noise in a series of acoustic image frames obtained by using a forward-looking imaging sonar. The time-series...
We proposed and tested a passive acoustic landmark that can provide accurate navigation information for an autonomous underwater vehicle (AUV). The AUV used imaging sonar mounted on the vehicle to recognize shadows of the column-type landmark, and can measure vehicle's own pose and relative position from the landmark which was set in a known position. The results of the proposed method had acceptable...
A method for automatic detection or recognition using high-frequency forward-looking imaging sonar is proposed. The method includes segmentation of an underwater object's echo shape or its acoustic shadow shape. For accuracy of segmentation, some constraints were assumed on the underwater ground and the sonar's pose. The separated shape was compared to simulated reference shapes to know its orientation...
In case of marine accident, the rapid search for missing object such as an underwater wreckage is one of the most important tasks. For this task, an autonomous underwater vehicle (AUV) that equips forward-looking imaging sonar can be utilized. The search task is accomplished by the following strategy. In the first phase, the AUV scans the target underwater area in a fast speed, and detects some suspected...
Underwater sonar image can be obtained by the multi-beam imaging sonar. Because of its high frame rate, the imaging sonar can be used for underwater survey especially in turbid water condition. However, the sonar image is generally degraded by the speckle noise. In this paper, we propose a realtime noise reduction algorithm by using the recursive least square algorithm, which is one of the adaptive...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.