• Title/Summary/Keyword: Shadow elimination

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Cast-Shadow Elimination of Vehicle Objects Using Backpropagation Neural Network (신경망을 이용한 차량 객체의 그림자 제거)

  • Jeong, Sung-Hwan;Lee, Jun-Whoan
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.1
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    • pp.32-41
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    • 2008
  • The moving object tracking in vision based observation using video uses difference method between GMM(Gaussian Mixture Model) based background and present image. In the case of racking object using binary image made by threshold, the object is merged not by object information but by Cast-Shadow. This paper proposed the method that eliminates Cast-Shadow using backpropagation Neural Network. The neural network is trained by abstracting feature value form training image of object range in 10-movies and Cast-Shadow range. The method eliminating Cast-Shadow is based on the method distinguishing shadow from binary image, its Performance is better(16.2%, 38.2%, 28.1%, 22.3%, 44.4%) than existing Cast-Shadow elimination algorithm(SNP, SP, DNM1, DNM2, CNCC).

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Comparisons of Color Spaces for Shadow Elimination (그림자 제거를 위한 색상 공간의 비교)

  • Lee, Gwang-Gook;Uzair, Muhammad;Yoon, Ja-Young;Kim, Jae-Jun;Kim, Whoi-Yul
    • Journal of Korea Multimedia Society
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    • v.11 no.5
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    • pp.610-622
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    • 2008
  • Moving object segmentation is an essential technique for various video surveillance applications. The result of moving object segmentation often contains shadow regions caused by the color difference of shadow pixels. Hence, moving object segmentation is usually followed by a shadow elimination process to remove the false detection results. The common assumption adopted in previous works is that, under the illumination variation, the value of chromaticity components are preserved while the value of intensity component is changed. Hence, color transforms which separates luminance component and chromaticity component are usually utilized to remove shadow pixels. In this paper, various color spaces (YCbCr, HSI, normalized rgb, Yxy, Lab, c1c2c3) are examined to find the most appropriate color space for shadow elimination. So far, there have been some research efforts to compare the influence of various color spaces for shadow elimination. However, previous efforts are somewhat insufficient to compare the color distortions under illumination change in diverse color spaces, since they used a specific shadow elimination scheme or different thresholds for different color spaces. In this paper, to relieve the limitations of previous works, (1) the amount of gradients in shadow boundaries drawn to uniform colored regions are examined only for chromaticity components to compare the color distortion under illumination change and (2) the accuracy of background subtraction are analyzed via RoC curves to compare different color spaces without the problem of threshold level selection. Through experiments on real video sequences, YCbCr and normalized rgb color spaces showed good results for shadow elimination among various color spaces used for the experiments.

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Efficient Learning and Classification for Vehicle Type using Moving Cast Shadow Elimination in Vehicle Surveillance Video (차량 감시영상에서 그림자 제거를 통한 효율적인 차종의 학습 및 분류)

  • Shin, Wook-Sun;Lee, Chang-Hoon
    • The KIPS Transactions:PartB
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    • v.15B no.1
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    • pp.1-8
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    • 2008
  • Generally, moving objects in surveillance video are extracted by background subtraction or frame difference method. However, moving cast shadows on object distort extracted figures which cause serious detection problems. Especially, analyzing vehicle information in video frames from a fixed surveillance camera on road, we obtain inaccurate results by shadow which vehicle causes. So, Shadow Elimination is essential to extract right objects from frames in surveillance video. And we use shadow removal algorithm for vehicle classification. In our paper, as we suppress moving cast shadow in object, we efficiently discriminate vehicle types. After we fit new object of shadow-removed object as three dimension object, we use extracted attributes for supervised learning to classify vehicle types. In experiment, we use 3 learning methods {IBL, C4.5, NN(Neural Network)} so that we evaluate the result of vehicle classification by shadow elimination.

An Effective Shadow Elimination Method Using Adaptive Parameters Update (적응적 매개변수 갱신을 통한 효과적인 그림자 제거 기법)

  • Kim, Byeoung-Su;Lee, Gwang-Gook;Yoon, Ja-Young;Kim, Jae-Jun;Kim, Whoi-Yul
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.3
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    • pp.11-19
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    • 2008
  • Background subtraction, which separates moving objects in video sequences, is an essential technology for object recognition and tracking. However, background subtraction methods are often confused by shadow regions and this misclassification of shadow regions disturbs further processes to perceive the shapes or exact positions of moving objects. This paper proposes a method for shadow elimination which is based on shadow modeling by color information and Bayesian classification framework. Also, because of dynamic update of modeling parametres, the proposed method is able to correspond adaptively to illumination changes. Experimental results proved that the proposed method can eliminate shadow regions effectively even for circumstances with varying lighting condition.

Traffic flow measurement system using image processing

  • Hara, Takaaki;Akizuki, Kageo;Kawamura, Mamoru
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.426-439
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    • 1996
  • In this paper, we propose a simple algorithm to calculate the numbers of the passing cars by using an image processing sensor for the digital black and white images with 256 tone level. Shadow is one of the most troublesome factor in image processing. By differencing the tone level, we cannot discriminate between the body of the car and its shadow. In our proposed algorithm, the area of the shadow is excluded by recognizing the position of each traffic lane. For real-time operation and simple calculation, two lines of the tone level are extracted and the existences of cars are recognized. In the experimental application on a high-way, the recognition rate of the real-time operation is more than 94%.

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An Efficient Shadow Removal Technique adapted to Environmental Changes (환경변화에 적응하는 효율적인 그림자 제거 기법)

  • Ryu, Nam-Hoon;Ban, Kyeong-Jin;Oh, Kyeong-Sug;Kim, Eung-Kon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.4 no.3
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    • pp.204-210
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    • 2009
  • There has been a lot of research into a background separation method, which is a preprocess of a technique of automatically perceiving an invader, and the removal of shadows around a moving object in the video monitoring field. When a moving object is not clearly separated from its shadow, it is difficult to analyze the shape accurately, and it is also hard to trace its position. This study suggests how to utilize a brightness value for removing a shadow. It came from the fact that there appears to be no change of color in the shadow area relative to the background area, and there only occurs a difference in brightness. In addition, this method uses the renewal of a critical value used for the removal of shadow in the previous frame, in the next frame.

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Distortion Corrected Black and White Document Image Generation Based on Camera (카메라기반의 왜곡이 보정된 흑백 문서 영상 생성)

  • Kim, Jin-Ho
    • The Journal of the Korea Contents Association
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    • v.15 no.11
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    • pp.18-26
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    • 2015
  • Geometric distortion and shadow effect due to capturing angle could be included in document copy images that are captured by a camera in stead of a scanner. In this paper, a clean black and white document image generation algorithm by distortion correction and shadow elimination based on a camera, is proposed. In order to correct geometric distortion such as straightening un-straight boundary lines occurred by camera lens radial distortion and eliminating outlying area included by camera direction, second derivative filter based document boundary detection method is developed. Black and white images have been generated by adaptive binarization method by eliminating shadow effect. Experimental results of the black and white document image generation algorithm by recovering geometrical distortion and eliminating shadow effect for the document images captured by smart phone camera, shows very good processing results.

Vehicle Shadow Detection in Thermal Videos (열 영상에서의 차량 그림자 제거 기법)

  • Kim, Ji-Man;Choi, Eun-Ji;Lim, Jeong-Eun;Noh, Seung-In;Kim, Dai-Jin
    • Proceedings of the Korean Information Science Society Conference
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    • 2012.06b
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    • pp.369-371
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    • 2012
  • Shadow detection and elimination is a critical issue in vision-based system to improve the detection performance of moving objects. However, traditional algorithms are useless at night time because they used the chromaticity and brightness information from the color image sequence. To obtain the high detection performance, we can use the thermal camera and there are shadows by the heat not the light. We proposed a novel algorithm to detect and eliminate the shadows using the thermal intensity and the locality property. By combining two results of the intensity-based and locality-based, we can detect the shadows by the heat and improve the detection performance of moving object.

A Video Traffic Flow Detection System Based on Machine Vision

  • Wang, Xin-Xin;Zhao, Xiao-Ming;Shen, Yu
    • Journal of Information Processing Systems
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    • v.15 no.5
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    • pp.1218-1230
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    • 2019
  • This study proposes a novel video traffic flow detection method based on machine vision technology. The three-frame difference method, which is one kind of a motion evaluation method, is used to establish initial background image, and then a statistical scoring strategy is chosen to update background image in real time. Finally, the background difference method is used for detecting the moving objects. Meanwhile, a simple but effective shadow elimination method is introduced to improve the accuracy of the detection for moving objects. Furthermore, the study also proposes a vehicle matching and tracking strategy by combining characteristics, such as vehicle's location information, color information and fractal dimension information. Experimental results show that this detection method could quickly and effectively detect various traffic flow parameters, laying a solid foundation for enhancing the degree of automation for traffic management.