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We propose an imaging sonar-based backtracking method as a navigation strategy for an underwater investigation of AUVs. The purpose of backtracking method is to reduce a drift error caused by the inaccuracy of navigation sensors when an AUV returns to its previous position. The AUV divides the trajectory into several intervals and returns to the previous position while correcting small drift error...
In this paper, we propose a backtracking method of AUV based on optical and acoustic image evaluation. With the proposed method, the vehicle can record useful images on its path, and conduct backtracking efficiently and robustly even in turbid water. At each point during the exploration, AUV chooses better image between optical and acoustic image by feature detection. The chosen image is saved in...
Autonomous underwater vehicles (AUVs) have been widely used for many risky underwater tasks. For these tasks, AUVs require navigational aids, such as active beacon-type underwater acoustic landmarks, which are the most widely used. It requires heavy installation loads and regular maintenance with high price sensors. In this paper, we propose a novel localization method in shallow water with a multi-beam...
To reduce deployment and maintenance costs, a novel wave energy converter (WEC) is proposed for mooring-less sensor buoys. The design concept is based on a small size WEC capable of harvesting wave energy without mooring, which can reduce the installation cost. The proposed wave energy converter consists of a submerged and a floating body, and the submerged body is a self-rectifying wave-induced turbine...
Underwater vision has specific characteristics such as high attenuation of lights, severe noise and haze in the images. For real-time fish detection using underwater vision, this paper proposes convolutional neural network based techniques based on You Only Look Once algorithm. Actual fish video images were used to evaluate the reliability and accuracy of the proposed method. As a result, the network...
Wave energy is obvious source for renewable energy harvesting in oceans. A new WEC named wave turbine was proposed. The proposed system consists of a floating body and a submerged body. The floating body is same with that of a conventional buoy, and the submerged body is a power take off similar to a turbine which has flap-type blades in a round-frame rotor. To describe the proposed system, we developed...
We proposed man-made underwater landmark and acoustic beam-based landmark detection method. Beams in multi-beam sonar are independent each other, and each beam can be assumed as a feature to distinguish interesting area. When beam passes the object, the column array of sonar image is composed highlighted and shadow areas. Using these property, it is possible to recognize the underwater landmark by...
We propose a real-time underwater object detection algorithm using forward-looking imaging sonar. Considering the characteristics of sonar image, the Haar-like feature is used to construct each weak classifier. We construct a strong classifier by combining several weak classifiers. An adaptive Boosting (AdaBoost) algorithm is utilized to determine coefficients of each weak classifier and weights of...
In this paper, we proposed identification methods for hovering type Autonomous underwater vehicle (AUV) based on neuro fuzzy network. We conducted sea trial using Cyclops which is hovering type AUV. [1] We verified the proposed identification method from the sea trial.
An autonomous underwater camera is developed for monitoring the red snow crab habitat in deep sea. Most of the deep sea cameras are designed such that they can be used with special deep sea exploration instruments such as underwater vehicles. However, a developed camera can be attached to the fish traps for catching the red snow crab, and fishermen who are not underwater camera experts can handle...
A typical sonar image has a plenty of random noise compared to an optical image. Due to poor picture quality, there is a large restriction on recognizing any object. Pattern recognition is exceedingly difficult not only in computer image processing but even in human eyes. Numerous researchers have attempted to apply various types of average filters to sonar images, and have also removed noise by using...
The typical autonomous underwater vehicles (AUVs) are widely used in underwater exploration. However, there are difficulties to use AUVs in constrained environments such as the strong current or poor visibility. In this paper, we proposed the novel design and operation strategy of AUV that can overcome these restricted condition. The proposed AUV is composed by upper and lower body with specific technologies...
To realize moor-less buoy which keeps position on the deep sea without an anchor, the moor-less buoy system was proposed [1]. The system adopted ‘Wave Glider’ [2] as a propulsion unit, which could make thrust by ocean wave energy without extra energy like battery. However, there are always a risk to be swept away by ocean current, because ocean wave and ocean current are irregular. In this paper,...
Underwater observation is important technology for marine research. However, limited visibility of sea water, it takes long time to collect wide images and data. In this paper, we propose novel underwater observation system named SWAN. SWAN is multi-agent system composed of the main AUV and agents. The agents are linked by tethers with the main AUV. It enables that the main AUV could track the agents...
It is still hard mission for human divers or robotic systems to investigate complex underwater environments, composed of several turning points and rooms. This paper explains a design of the Autonomous Underwater Vehicle (AUV) for marking physical and visible path logs in water. Then, it will make the repeated exploration easier. For the solution of underwater marking, we chose to use paraffin wax...
We propose a robot, named Iceberg worm, clinging to lower surface of ice shelf (or iceberg) for ice thickness measurement. The key technologies of the proposed robot are 1) Inverse buoyancy setting and adjustable buoyancy control system; 2) Biomimetic legs and crampons like insects feet; 3) Non-contact laser-ultrasonic ranging system; 4) Acoustic-taxis navigation like positive photo-taxis of bugs...
We proposed an autonomous trajectory backtracking method using forward-looking imaging sonar. Additionally, we also dealt with a Fourier-based sonar image processing for the autonomous trajectory backtracking. We suggested an algorithm to estimate translational shifts and rotation angle between two sonar images. By feeding back the estimated data, AUV can compensate the drift error of dead-reckoning...
Agent system is strategy to enhance the underwater manipulation. The conventional manipulation is generally robot arm-based configuration which has singular points. On the other hand, the agent system is an armless manipulation that the agent vehicle works as the end-effector. If the location of the agent can be measured, the end effector is able to be place to any position. To implement this system,...
In this paper, we studied some pre-process methods that make the feature matching faster, accurate and proper to be used in the photo mosaic process. Two properties and two image processing technique were considered: channel, size, contrast enhancement, and Gaussian smoothing. We investigated how they affect the feature quantity and matching result by controling related parameters. The smallest number...
The robotic buoy which is a mobile mooringless buoy and keeps position autonomously against ocean current.[1][2][3] The robotic buoy is specialized for operating on an environment where is too deep to anchor for mooring, like middle of an ocean. The robotic buoy is compose of two systems, propulsion system and energy harvesting system. ‘Wave Turbine’ is a PTO(Power take-off)[4] to harvest oceanic...
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