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In order to understand the underwater environment, it is essential to use sensing methodologies able to perceive the three dimensional (3D) information of the explored site. Sonar sensors are commonly employed in underwater exploration. This paper presents a novel methodology able to retrieve 3D information of underwater objects. The proposed solution employs an acoustic camera, which represents the...
Spherical cameras are widely used due to their full 360$^\circ$ fields of view. However, a common but severe problem is that anything carrying the camera is always included in the view, occluding visual information. In this letter, we propose a novel method to remove such occlusions in videos taken from a freely moving spherical camera. Our method can recover the occluded background accurately in...
Search robotics involves the use of autonomous systems which have to operate in unknown environments and interact with external objects or humans. Typically, these robots are equipped with sensors which are used to perceive the surrounding scenario and feed it back to the human operator. Besides the extensive research effort, a sensory system able to reproduce the human “sense of touch” is still missing...
In this paper, we propose a method to correct the over- and underexposed regions in images. For the correction of over- and underexposed regions, multiple light sources are used to obtain several images whose over- and underexposed regions are in different positions. The image processing consists of four steps. Firstly, multiple images are captured by alternately turning on and off the illuminations...
During the teleoperation of construction machines, it is highly needed to visualize the machine body itself. This is because the operator needs to perform a visual confirmation of the construction machine. In addition, information of crawler parts' shoe slip is indispensable. Therefore, not only the surrounding environment but also the vehicle body are needed to be visualized. This paper proposes...
Spherical cameras are widely used for robot perception because of their full 360 degree fields of view. However, the robot body is always seen in the view, causing occlusions. In this paper, we propose a video completion method which is able to remove occlusions fast and recover the occluded background accurately. We first estimate motion in a 2D dense spherical optical flow field. Then we interpolate...
In this research, a technique for dense 3D reconstruction from two spherical images clicked at displaced positions near a large structure is formulated. The technique is based on the use of global variational information i.e. the dense optical flow field in a unique rectification based refinement of the epipolar geometry between the two images in a vertically displaced orientation. A non-linear minimization...
In this research, a method for dense 3D reconstruction of structures from small motion of a spherical camera is proposed. Spherical cameras can capture information from all directions enabling measurement of the entire surrounding structure at once. The proposed technique uses two spherical images clicked at slightly displaced positions near the structure, followed by a combination of feature-point...
This paper presents a novel scheme for the three-dimensional (3D) reconstruction of underwater objects by using multiple acoustic views based on geometric and image processing approaches. Underwater tasks such as maintenance, ship hull inspection, and harbor surveillance require accurate underwater information. In such cases, 3D reconstructed information would greatly contribute to a better understanding...
In camera-equipped teleoperated robots, it is often tedious for the operator to manage both the viewpoint and the shaky/unstable navigation, leading to disorientation. Our proposal is to create a virtual, freely rotatable camera that is decoupled from the robot's rotation. It is implemented using a complete spherical camera and removing its rotation in-image with a novel algorithm based on aligning...
Three-dimensional (3D) measurement is an important means for robots to acquire information about their environment. Structure from Motion is one of these 3D measurement methods. The 3D reconstruction of objects in the environment can be obtained from pictures captured with single camera in Structure from Motion. Furthermore, the camera motion can be obtained simultaneously. Because of its simplicity,...
This paper proposes a human face tracking system for obtaining elderly people's facial images, which can be used to estimate their individual emotion. Quadrotors are used to overcome occlusion and obtain closer facial images, while Kinect sensors provide human detection and quadrotor navigation. Noise from the measured head position results in vibration of the goal position, and subsequently the quadrotor,...
In camera images for urban search and rescue (USAR) robots teleoperation, it is important to reduce blind spots and get surroundings as much as possible because of safety requirements. We propose a method to create synthesized bird's-eye view images from multiple fish-eye cameras as spatiotemporal data which can reduce blind spots. In practical use, it is very important to get images robustly even...
In this paper, we propose a method for a mobile robot to navigation in textureless environment using an omni-directional camera. The method makes an environment map consisting of 3D edge points obtained from omni-directional camera images and estimates the locations of planes by analysing these 3D edge points so that the robot can autonomously travel while avoiding walls as obstacles. The method has...
In this paper, we propose an efficient estimation method of an omnidirectional camera movement. The proposed method is based on Structure from Motion utilizing a constraint of parallel lines. In an environment having manmade structures, parallel lines can be extracted from an omnidirectional image easily and constantly, because of its wide field of view. Parallel lines provides a valuable constraint...
View occluders influence the image quality of a subject when occluders exist between a camera and a subject. For example, a blurred fence image interrupts a subject when an image of a scene is captured by a camera through a fence. In this paper, we propose an automatic removal method of foreground occluders from images using multiple focusing. Our method automatically detects foreground occluder regions...
A lot of plumbings such as gas pipes and water pipes exist in public utilities, factories and so on. The use of an omni-directional camera which can take images of 360 deg in surroundings at a time is effective for pipe inspection. However, shape measurement is difficult only with the omnidirectional camera. Therefore, in this paper, we propose a reconstruction method of a piping shape by using a...
In this paper, we propose an underwater sensing method by using an omni-directional stereo camera system. When observing objects in water through a camera contained in a waterproof housing or observing objects in an aquarium tank filled with preserving liquid, we should solve a problem of light refraction at the boundary surfaces of refractive index discontinuity which gives image distortion. The...
Map information is important for path planning and selflocalization when mobile robots accomplish autonomous tasks. In unknown environments, they should generate environment maps by themselves. An omnidirectional camera is effective for environment measurement, because it has a wide field of view. There are binocular stereo and motion stereo in traditional methods for measurement by omnidirectional...
In this paper, we propose an assisting system of touch panel operation for people with visual disability. In the system, a user specifies the target button on the panel by verbal input. The system detects the button and user's fingertip by analyzing images obtained through stereo camera. Navigation is made by indicating the direction of the fingertip on the panel through headphones with sound. To...
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