• 대한임베디드공학회논문지
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• 제13권4호
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• pp.169-178
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• 2018

Currently, various sensors have been used for advanced driver assistance systems. In order to overcome the limitations of individual sensors, sensor fusion has recently attracted the attention in the field of intelligence vehicles. Thus, vision and radar based sensor fusion has become a popular concept. The typical method of sensor fusion involves vision sensor that recognizes targets based on ROIs (Regions Of Interest) generated by radar sensors. Especially, because AVM (Around View Monitor) cameras due to their wide-angle lenses have limitations of detection performance over near distance and around the edges of the angle of view, for high performance of sensor fusion using AVM cameras and radar sensors the exact ROI extraction of the radar sensor is very important. In order to resolve this problem, we proposed a sensor fusion scheme based on commercial radar modules of the vendor Delphi. First, we configured multiple radar data logging systems together with AVM cameras. We also designed radar post-processing algorithms to extract the exact ROIs. Finally, using the developed hardware and software platforms, we verified the post-data processing algorithm under indoor and outdoor environments.

• 대한전자공학회논문지SP
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• 제44권1호
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• pp.1-9
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• 2007

본 논문에서는 임의 시점에서의 장면을 생성하기 위한 3차원 모델링 및 렌더링 시스템을 제안한다. 제안되는 시스템은 공간상에 설치된 복수의 스테레오 카메라와 PC들로 구성되며 UDP를 이용해 연결되어 각 카메라에서 획득되고 분석된 영상 데이터들을 모델링 PC로 전송해 실시간으로 3차원 모델을 생성하고, 이로부터 사용자가 원하는 위치에서의 장면을 생성해 디스플레이 하게 된다. 제안된 알고리듬은 성능 평가 결과 기존의 알고리듬보다 좋은 성능을 보였으며, 구현된 시스템은 실시간으로 사용자에게 원하는 시점에서의 영상을 자연스럽게 제공함을 실험을 통해 검증하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.136-141
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• 2009

This paper proposed a framework for handover method in continuously tracking a person of interest across cooperative pan-tilt-zoom (PTZ) cameras. The algorithm here is based on a robust non-parametric technique for climbing density gradients to find the peak of probability distributions called the mean shift algorithm. Most tracking algorithms use only one cue (such as color). The color features are not always discriminative enough for target localization because illumination or viewpoints tend to change. Moreover the background may be of a color similar to that of the target. In our proposed system, the continuous person tracking across cooperative PTZ cameras by mean shift tracking that using color and shape histogram to be feature distributions. Color and shape distributions of interested person are used to register the target person across cameras. For the first camera, we select interested person for tracking using skin color, cloth color and boundary of body. To handover tracking process between two cameras, the second camera receives color and shape cues of a target person from the first camera and using linear color calibration to help with handover process. Our experimental results demonstrate color and shape feature in mean shift algorithm is capable for continuously and accurately track the target person across cameras.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.939-945
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• 2009

In this paper, we proposed a method which corresponds people under the structured spaces with multiple cameras. The correspondence takes an important role for using multiple camera system. For solving this correspondence, the proposed method consists of three main steps. Firstly, moving objects are detected by background subtraction using a multiple background model. The temporal difference is simultaneously used to reduce a noise in the temporal change. When more than two people are detected, those detected regions are divided into each label to represent an individual person. Secondly, the detected region is segmented as features for correspondence by a criterion with the color distribution and context information of human body. The segmented region is represented as a set of blobs. Each blob is described as Gaussian probability distribution, i.e., a person model is generated from the blobs as a Gaussian Mixture Model (GMM). Finally, a GMM of each person from a camera is matched with the model of other people from different cameras by maximum likelihood. From those results, we identify a same person in different view. The experiment was performed according to three scenarios and verified the performance in qualitative and quantitative results.

• Current Optics and Photonics
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• 제8권3호
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• pp.246-258
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• 2024

In aerospace and energy engineering, the reconstruction of three-dimensional (3D) temperature distributions is crucial. Traditional methods like algebraic iterative reconstruction and filtered back-projection depend on voxel division for resolution. Our algorithm, blending deep learning with computer graphics rendering, converts 2D projections into light rays for uniform sampling, using a fully connected neural network to depict the 3D temperature field. Although effective in capturing internal details, it demands multiple cameras for varied angle projections, increasing cost and computational needs. We assess the impact of camera number on reconstruction accuracy and efficiency, conducting butane-flame simulations with different camera setups (6 to 18 cameras). The results show improved accuracy with more cameras, with 12 cameras achieving optimal computational efficiency (1.263) and low error rates. Verification experiments with 9, 12, and 15 cameras, using thermocouples, confirm that the 12-camera setup as the best, balancing efficiency and accuracy. This offers a feasible, cost-effective solution for real-world applications like engine testing and environmental monitoring, improving accuracy and resource management in temperature measurement.

• 대한전자공학회논문지SP
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• 제48권3호
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• pp.13-18
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• 2011

본 논문에서는 다시점 색상 카메라와 다시점 깊이 카메라를 이용하여 촬영한 영상의 후처리 방법과 3차원 장면의 깊이 정보를 생성하는 방법을 제안한다. 깊이 카메라는 장면의 깊이 정보를 실시간으로 측정할 수 있는 장점이 있지만, 잡음과 왜곡이 발생하고 색상 영상과의 상관도도 떨어진다. 따라서 다시점 깊이 영상에 후처리 작업을 수행한 후, 이를 다시점 색상 영상과 조합하여 3차원 깊이 정보를 생성한다. 깊이 카메라로부터 얻은 각 시점에서의 초기 변이 정보를 기반으로 한 스테레오 정합의 결과는 기존 방법의 결과 보다 우수한 성능을 나타내었음을 볼 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2075-2092
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• 2017

Person re-identification is to match pedestrians observed from non-overlapping camera views. It has important applications in video surveillance such as person retrieval, person tracking, and activity analysis. However, it is a very challenging problem due to illumination, pose and viewpoint variations between non-overlapping camera views. In this work, we propose a viewpoint invariant method for matching pedestrian images using orientation of pedestrian. First, the proposed method divides a pedestrian image into patches and assigns angle to a patch using the orientation of the pedestrian under the assumption that a person body has the cylindrical shape. The difference between angles are then used to compute the similarity between patches. We applied the proposed method to real-time global multi-object tracking across multiple disjoint cameras with non-overlapping field of views. Re-identification algorithm makes global trajectories by connecting local trajectories obtained by different local trackers. The effectiveness of the viewpoint invariant method for person re-identification was validated on the VIPeR dataset. In addition, we demonstrated the effectiveness of the proposed approach for the inter-camera multiple object tracking on the MCT dataset with ground truth data for local tracking.

• IEIE Transactions on Smart Processing and Computing
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• 제4권4호
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• pp.224-230
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• 2015

This manuscript presents a real-time solution for 3D human body reconstruction with multiple RGB-D cameras. The proposed system uses four consumer RGB/Depth (RGB-D) cameras, each located at approximately $90^{\circ}$ from the next camera around a freely moving human body. A single mesh is constructed from the captured point clouds by iteratively removing the estimated overlapping regions from the boundary. A cell-based mesh construction algorithm is developed, recovering the 3D shape from various conditions, considering the direction of the camera and the mesh boundary. The proposed algorithm also allows problematic holes and/or occluded regions to be recovered from another view. Finally, calibrated RGB data is merged with the constructed mesh so it can be viewed from an arbitrary direction. The proposed algorithm is implemented with general-purpose computation on graphics processing unit (GPGPU) for real-time processing owing to its suitability for parallel processing.

• 전기학회논문지
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• 제60권2호
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• pp.441-445
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• 2011

In this paper, we propose an algorithm for generating panoramic videos using fixed multiple cameras. We estimate a background image from each camera. Then we calculate perspective relationships between images using extracted feature points. To eliminate stitching errors due to different image depths, we process background images and foreground images separately in the overlap regions between adjacent cameras by projecting regions of foreground images selectively. The proposed algorithm can be used to enhance the efficiency and convenience of wide-area surveillance systems.

• 한국전자통신학회논문지
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• 제9권10호
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• pp.1189-1195
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• 2014

본 연구에서는 동일한 환경에서 스마트폰 카메라에서 촬영한 여러 장의 영상들로부터 얻을 수 있는 정보를 활용하여 영상 잡음을 효과적으로 제거할 수 있는 알고리즘을 개발한다. 이를 위해 스마트폰의 제한된 연산능력에 맞는 다중 영상 정합(registration) 알고리즘을 개발하고, 다중 영상들의 정보들을 조합하여 효과적으로 영상 잡음을 제거하는 방법을 제시한다. 제시한 알고리즘을 정량적으로 잡음 제거 성능을 측정하기 위해 PSNR 값으로 비교 시 단일 영상을 이용할 때보다 훨씬 향상된 PSNR 값 향상을 가져왔다. 실제 안드로이드 스마트폰에 해당 알고리즘을 개발하여, 실제 사용 가능한 수준의 영상 처리 속도로 만족할만한 잡음 제거 효과를 얻을 수 있음을 확인하였다.