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This paper proposes a practical system of the fish size measurement which is effective and simple. Because the fry we measured is very small, the main technical problem when we measure the fish size is to measure accurately without hurting them. Although the live fish can be measured directly or after anesthesia, the fry will be damaged. So we present the system of fish size measurement without any...
This paper proposes an underwater 3D reconstruction method based on laser line scanning. 3D reconstruction of underwater target is an important technology in ocean development. Due to the complicated underwater environment, underwater 3D reconstruction is still a challenge. The traditional underwater object detection is mainly based on acoustic technology, but acoustic technology can't meet the demands...
Due to the light attenuation caused by absorption and scattering of sea water, the performance of underwater optical communication system is limited. Usually, the optical signals will be decayed severely in hundreds of meters and the waveforms are submerged in noise. To improve the signal-to-noise ratio (SNR), for traditional methods, most of the noise can be suppressed by filters based on classic...
We propose a comprehensive method using multiscale and multicycle features for retinal vessel image registration with a local and global strategy. The multiscale vessel maps generated by multiwavelet kernels and multiscale hierarchical decomposition contain segmentation results at varying image resolutions in different levels of vessel details. Then the multicycle feature composed of various combinations...
To conserve and manage fish stocks in fisheries, people monitor the growth and quantities of fish by collected underwater videos and images. However, the efficiency of finding fish from videos and images is limited by manual operation. In this paper, we propose an automatic method to improve the efficiency of finding fish by shape matching. In our method, a segmentation method, Segmentation by Aggregating...
Underwater object detection and segmentation has been attracting a lot of interest, and recently various systems have been designed. In this paper, we introduce a novel technique to automatically detect and segment objects from underwater images via saliency-based region merging. The method is composed of three main steps. Firstly, a salient object detection model is used to detect the position of...
Zooplankton are the key components of marine food webs. The abundance of it influences the ocean ecological balance. To efficiently monitor species richness of zooplankton and protect marine environment, marine biologists and computer vision experts started to research automated zooplankton classification system with computer vision technologies. Most current research focuses on achieving high classification...
Zooplankton are quite significant to the ocean ecosystem for stabilizing balance of the ecosystem and keeping the earth running normally. Considering the significance of zooplantkon, research about zooplankton has caught more and more attentions. And zooplankton recognition has shown great potential for science studies and mearsuring applications. However, manual recognition on zooplankton is labour-intensive...
Moving object detection is the basis of object tracking and classification in computer vision, which has been applied to underwater robots to execute underwater missions and do marine ecological research. The complicated scene and poor lighting condition in underwater environment usually make moving object detection difficult. To solve above problems and to detect moving object from underwater video,...
Chaetoceros is one of the largest marine genus of phytoplankton and plays an important role in ocean ecosystem and global climate. Automatic segmentation of Chaetoceros is a challenging task due to the species' biomorphic characteristics. In this paper, we present a novel method using pixel-wise classification by Support Vector Machine (SVM) [1] combined with Grayscale Surface Direction Angle Model...
Due to the dramatic effect of scattering caused by underwater medium, blur commonly occurs in underwater images. Moreover, colors are frequently attenuated in underwater situations, in response to the effect that water selectively absorbs light of different wavelengths. Thus, this color loss becomes one of the key features of underwater images. Most present blur/sharpness evaluation algorithms, which...
Phytoplankton are photosynthesizing microscopic organisms that inhabit the upper sunlit layer of almost all oceans and bodies of fresh water. Its abundance and taxonomic composition have impact on marine ecosystem dynamic and global environment change. Therefore, many researchers pay attention to effectively monitoring phytoplankton quantity and species composition. In order to realize this purpose,...
Underwater image segmentation is a key step for the analysis of the underwater target as segmentation quality will directly affect the stability and reliability of target recognition and tracking. A novel segmentation method is proposed in this paper that can help to solve the edge expansion and contour deformation problems in traditional segmentation methods. Firstly, the dark channel prior algorithm...
Techniques of fixed pattern noise reduction for CMOS image sensor are presented. Double sampling reusing the existing switch-capacitor amplifier of column ADC, double resets for 5-T active pixel, and negative offset storage of the cyclic ADC, are proposed to reduce the fixed pattern noise caused by the threshold voltage's mismatch of the amplifying and transmitting transistor of the pixel, and the...
One of the key problem in underwater imaging detection is to overcome backscatter effect. It causes the decrease of image quality. Under normal illumination condition high power in the close range engender great backscatter and low power in the far distance limit detection range. In order to solve this problem, an inhomogeneous illumination system was built. The power distribution of inhomogeneous...
Underwater 3-D visual technology is one of key technologies in deep sea detection and operation. To acquire underwater depth information of target object is a key point of underwater 3-D visual technology. In this paper, based on active triangular method, we propose a method through laser frequency-difference scanning technology to obtain depth information from 2-D image. We verify the accuracy of...
The experiments showed that the structure of artificial neural networks and parameters strongly influenced the performance of the network [1]. If the network structure is too simple, it will lower the classification capacity of the network, thus affecting the final recognition result. If the network structure is too complex it will slower the learning speed and eventually the final error may increase...
For underwater target detection by homogeneous illumination or laser, the strong backscattering is mainly generated at the range close to the detector, yielding low visibility. Therefore, we build the underwater imaging system based on inhomogeneous illumination field, which intensity distribution relates to the attenuation pattern of light transmission with an inverse form. It is shown via pool and...
This paper presents a new approach for underwater 3D target positioning by inhomogeneous illumination based on binocular stereo vision. Based on the theory of inhomogeneous illumination field, we build underwater binocular stereo vision system to measure the distance between the target and the detector (CCD receiver) as well as the 3D information of the target, which can be used to the further 3D...
Underwater imaging systems using homogeneous illumination or a laser generate strong backscattering close to the detector, yielding low visibility. This paper considers an underwater imaging system based on inhomogeneous illumination, so that the intensity distribution is related to the light attenuation pattern. It is shown via pool and sea experiments to be effective in decreasing back-scattering...
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