• Title/Summary/Keyword: ocean image

Search Result 685, Processing Time 0.025 seconds

A method for underwater image analysis using bi-dimensional empirical mode decomposition technique

  • Liu, Bo;Lin, Yan
    • Ocean Systems Engineering
    • /
    • v.2 no.2
    • /
    • pp.137-145
    • /
    • 2012
  • Recent developments in underwater image recognition methods have received large attention by the ocean engineering researchers. In this paper, an improved bi-dimensional empirical mode decomposition (BEMD) approach is employed to decompose the given underwater image into intrinsic mode functions (IMFs) and residual. We developed a joint algorithm based on BEMD and Canny operator to extract multi-pixel edge features at multiple scales in IMFs sub-images. So the multiple pixel edge extraction is an advantage of our approach; the other contribution of this method is the realization of the bi-dimensional sifting process, which is realized utilizing regional-based operators to detect local extreme points and constructing radial basis function for curve surface interpolation. The performance of the multi-pixel edge extraction algorithm for processing underwater image is demonstrated in the contrast experiment with both the proposed method and the phase congruency edge detection.

Prelaunch Radiometric Performance Analysis of Ocean Scanning Multi-spectral Imager (OSMI)

  • Cho, Young-Min
    • Korean Journal of Remote Sensing
    • /
    • v.16 no.2
    • /
    • pp.135-143
    • /
    • 2000
  • Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-Purpose SATellite (KOMPSAT) to perform global ocean color monitoring for the study of biological oceanography. HOMPSAT was launched 21 December 1999. The radiometric performance of OSMI is analyzed for various gain settings in the viewpoint of the instrument developer for OSMI calibration and application based on its ground performance data measured before launch. The radiometric response linearity and dynamic range are analyzed and the dynamic range is compared with the nominal input radiance for the ocean and the land. The noise equivalent radiance (NER) corresponding to the instrument radiometric noise is compared with the radiometric resolution of signal digitization (1-count equivalent radiance). The best gain setting of OSMI for ocean monitoring is recommended. This analysis is considered to be useful for the OSMI mission and operation planning, the OSMI image data calibration, and users' understanding about OSMI image quality.

Image Analysis for the Simultaneous Measurement of Underwater Flow Velocity and Direction (수중 유속 및 유향의 동시 측정을 위한 이미지 분석 기술에 관한 연구)

  • Dongmin Seo;Sangwoo Oh;Sung-Hoon Byun
    • Journal of Sensor Science and Technology
    • /
    • v.32 no.5
    • /
    • pp.307-312
    • /
    • 2023
  • To measure the flow velocity and direction in the near field of an unmanned underwater vehicle, an optical measurement unit containing an image sensor and a phosphor-integrated pillar that mimics the neuromasts of a fish was constructed. To analyze pillar movement, which changes with fluid flow, fluorescence image analysis was conducted. To analyze the flow velocity, mean force analysis, which could determine the relationship between the light intensity of a fluorescence image and an external force, and length-force analysis, which could determine the distance between the center points of two fluorescence images, were employed. Additionally, angle analysis that can determine the angles at which pixels of a digital image change was selected to analyze the direction of fluid flow. The flow velocity analysis results showed a high correlation of 0.977 between the external force and the light intensity of the fluorescence image, and in the case of direction analysis, omnidirectional movement could be analyzed. Through this study, we confirmed the effectiveness of optical flow sensors equipped with phosphor-integrated pillars.

Analysis and application of ocean currents information extracted from SAR satellite image (SAR 위성영상 해수유동 정보추출 및 활용)

  • Lee, Moon-Jin;Kim, Hey-Jin;Lee, Seung-Hyun;Hang, Key-Yong
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.13 no.4
    • /
    • pp.21-26
    • /
    • 2007
  • A study on analysis and application of ocean currents information extracted from SAR (Synthetic Aperture Radar) satellite image. The current information extracted from SAR satellite image is not real vector information but scalar information in normal direction of orbital path. To correct current information extracted from satellite image, observation of currents in the field is carried out at the same time and area as those of satellite image. In the analysis, current information extracted from satellite image is corrected by using observed ones. By this correction, the speed and the direction of current can be estimated. The extract current information seem to agree well with the observed ones.

  • PDF

Sea-bottom Sediments and Seafloor Acoustic Image by Side Scan Sonar on Sindu-ri Offshore (신두리 해안 Side Scan Sonar 해저면 음향영상과 해저퇴적물)

  • Woo, Han-Jun;Lee, Yong-Kuk;Jeong, Kap-Sik;Je, Jong-Geel;Park, Gun-Tae;Jung, Baek-Hun;Cho, Jin-Hyung;Kim, Seong-Ryul
    • Journal of the Korean earth science society
    • /
    • v.23 no.8
    • /
    • pp.707-721
    • /
    • 2002
  • Seafloor acoustic image data using the side scan sonar system were gathered on the Sindu-ri offshore near the Taean peninsula, middle western Korea. The relationship between the back-scattering acoustic intensity and the sea-bottom sediment properties was studied. And these two data sets were compared and interpreted with the water depth, respectively. Most of sediment properties were correlated well to the acoustic intensity, however the distribution patterns of the sea-bottom sediment and the seafloor acoustic image were not similar to each other except the rocky bottom area. The water depth was not only influential on the distribution pattern of seafloor acoustic image but also showed a linear relation with the sediment properties distribution.

Robust Lane Detection Algorithm for Autonomous Trucks in Container Terminal

  • Ngo Quang Vinh;Sam-Sang You;Le Ngoc Bao Long;Hwan-Seong Kim
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2023.05a
    • /
    • pp.252-253
    • /
    • 2023
  • Container terminal automation might offer many potential benefits, such as increased productivity, reduced cost, and improved safety. Autonomous trucks can lead to more efficient container transport. A robust lane detection method is proposed using score-based generative modeling through stochastic differential equations for image-to-image translation. Image processing techniques are combined with Density-Based Spatial Clustering of Applications with Noise (DBSCAN) and Genetic Algorithm (GA) to ensure lane positioning robustness. The proposed method is validated by a dataset collected from the port terminals under different environmental conditions and tested the robustness of the lane detection method with stochastic noise.

  • PDF

A Study on Image Preprocessing Methods for Automatic Detection of Ship Corrosion Based on Deep Learning (딥러닝 기반 선박 부식 자동 검출을 위한 이미지 전처리 방안 연구)

  • Yun, Gwang-ho;Oh, Sang-jin;Shin, Sung-chul
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.25 no.4_2
    • /
    • pp.573-586
    • /
    • 2022
  • Corrosion can cause dangerous and expensive damage and failures of ship hulls and equipment. Therefore, it is necessary to maintain the vessel by periodic corrosion inspections. During visual inspection, many corrosion locations are inaccessible for many reasons, especially safety's point of view. Including subjective decisions of inspectors is one of the issues of visual inspection. Automation of visual inspection is tried by many pieces of research. In this study, we propose image preprocessing methods by image patch segmentation and thresholding. YOLOv5 was used as an object detection model after the image preprocessing. Finally, it was evaluated that corrosion detection performance using the proposed method was improved in terms of mean average precision.

Computer Image Processing for AR Conceptional Display 3D Navigational Information (증강현실 개념의 항행정보 가시화를 위한 영상처리 기술)

  • Lee, Jung-Min;Lee, Kyung-Ho;Kim, Dae-Soek;Nam, Byeong-Wook
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2014.10a
    • /
    • pp.245-246
    • /
    • 2014
  • This paper suggests the navigation information display system which is based on augmented reality technology and especially focuses on image analysis technology. Navigator has to always confirm the information from marine electronic navigation devices and then they compare with the view of outside targets of the windows. During this 'head down' posture, they feel uncomfortable and sometimes it cause near-accidents such as collision or missing objects, because he or she cannot keep an eye on the front view of windows. Augmented reality can display both of information of virtual and real in a single display. Therefore we tried to adapt the AR technology to help navigators and have been studied and developed image pre-processing module as a previous research already. To analysis the outside view of the bridge window, we have extracted navigational information from the camera image by using image processing. This paper mainly describes about recognizing ship feature by haar-like feature and filtering region of interest area by AIS data, which are to improve accuracy of the image analysis.

  • PDF

Noise Removal of Radar Image Using Image Inpainting (이미지 인페인팅을 활용한 레이다 이미지 노이즈 제거)

  • Jeon, Dongmin;Oh, Sang-jin;Lim, Chaeog;Shin, Sung-chul
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.59 no.2
    • /
    • pp.118-124
    • /
    • 2022
  • Marine environment analysis and ship motion prediction during ship navigation are important technologies for safe and economical operation of autonomous ships. As a marine environment analysis technology, there is a method of analyzing waves by measuring the sea states through images acquired based on radar(radio detection and ranging) signal. However, in the process of deriving marine environment information from radar images, noises generated by external factors are included, limiting the interpretation of the marine environment. Therefore, image processing for noise removal is required. In this study, image inpainting by partial convolutional neural network model is proposed as a method to remove noises and reconstruct radar images.

Development of Two Dimensional Position Measuring Device for Floating Structure Using an Image Processing Method (이미지 프로세싱을 이용한 부유구조물의 2차원 위치 계측장치 개발)

  • 지명석;김성근;김상봉
    • Journal of Ocean Engineering and Technology
    • /
    • v.8 no.2
    • /
    • pp.166-172
    • /
    • 1994
  • This paper presents an image processing method for two dimensional position measurement of a floating structure. This method is based on image processing technique using concept of window and threshold processing to track the target object. The experimental results for position measurement of the target object in two dimensional water tank demonstrate the validity of this method.

  • PDF