• Title/Summary/Keyword: Canny operator

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Iris Change Analysis that Using Differential Image (차영상을 이용한 홍채 변화 분석)

  • 김남식;김장형
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.932-934
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    • 2003
  • In this paper, time, studied about method that can analyze iris change to using differential image of iris image that put interval and films and utilize as patient's health examination according to iris change. Time, Differential mage of iris image that put interval and films ran be used usefully to search early diagnosis of disease and unfolding process etc.. of disease by showing definitely change by tine. In the case of iris diagnostic system, iris outside area extracts iris area and uses Differential image of before filming image and image that film present to use canny edge detector as there is cay to extract iris area as do not help in diagnostic and change analyzed comparison.

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The morphological edge detector by using stack filters (스택여파기를 이용한 형태학적 영상 윤곽선 검출기)

  • Yoo, Ji-Sang;Kim, Sun-Yong;Moon, Gyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.7
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    • pp.1696-1705
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    • 1996
  • The theory of stack filtering, which is a generalization of median filtering, is used to the detection of intensity edges in noisey images. The proposed approach, called the Difference of Estimates(DoE) approach, is a new formulation of a morphological scheme which has been very sensitive to impulse noise. In this approach, stack filters are applied to a noisy image to obtain local estimates of the dilated and eroded versions of the noise-free image. Thresholding the difference between these two estimates yields the binary edge map. We find that this approach yields results comparable to those obtained with the Canny operator for images with additive Gaussian noise, burt works much better when the noise is impulsive.

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A Robust Edge Detection method using Van der Waerden Statistic (Waerden 통계량을 이용한 강인한 에지검출 방법)

  • 최명희;이호근;김주원;하영호
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.3
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    • pp.147-153
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    • 2004
  • This paper proposes an efficient edge detection using Van der Waerden statistic in original and noisy images. An edge is where the intensity of an image moves from a low value to a high value or vice versa. We describe a nonparametric Wilcoxon test and a parametric T test based on statistical hypothesis testing for the detection of edges. We use the threshold determined by specifying significance level $\alpha$, while Bovik, Huang and Munson consider the range of possible values of test statistics for the threshold. From the experimental results of edge detection, the T and Wilcoxon method perform sensitively to the noisy image, while the proposed Waerden method is robust over both noisy and noise-free images under $\alpha$=0.0005. Comparison with our statistical test and Sobel, LoG, Canny operators shows that Waerden method perform more effectively in both noisy and noise-free images.

A Noisy-Robust Approach for Facial Expression Recognition

  • Tong, Ying;Shen, Yuehong;Gao, Bin;Sun, Fenggang;Chen, Rui;Xu, Yefeng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.4
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    • pp.2124-2148
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    • 2017
  • Accurate facial expression recognition (FER) requires reliable signal filtering and the effective feature extraction. Considering these requirements, this paper presents a novel approach for FER which is robust to noise. The main contributions of this work are: First, to preserve texture details in facial expression images and remove image noise, we improved the anisotropic diffusion filter by adjusting the diffusion coefficient according to two factors, namely, the gray value difference between the object and the background and the gradient magnitude of object. The improved filter can effectively distinguish facial muscle deformation and facial noise in face images. Second, to further improve robustness, we propose a new feature descriptor based on a combination of the Histogram of Oriented Gradients with the Canny operator (Canny-HOG) which can represent the precise deformation of eyes, eyebrows and lips for FER. Third, Canny-HOG's block and cell sizes are adjusted to reduce feature dimensionality and make the classifier less prone to overfitting. Our method was tested on images from the JAFFE and CK databases. Experimental results in L-O-Sam-O and L-O-Sub-O modes demonstrated the effectiveness of the proposed method. Meanwhile, the recognition rate of this method is not significantly affected in the presence of Gaussian noise and salt-and-pepper noise conditions.

Automated Satellite Image Co-Registration using Pre-Qualified Area Matching and Studentized Outlier Detection (사전검수영역기반정합법과 't-분포 과대오차검출법'을 이용한 위성영상의 '자동 영상좌표 상호등록')

  • Kim, Jong Hong;Heo, Joon;Sohn, Hong Gyoo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4D
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    • pp.687-693
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    • 2006
  • Image co-registration is the process of overlaying two images of the same scene, one of which represents a reference image, while the other is geometrically transformed to the one. In order to improve efficiency and effectiveness of the co-registration approach, the author proposed a pre-qualified area matching algorithm which is composed of feature extraction with canny operator and area matching algorithm with cross correlation coefficient. For refining matching points, outlier detection using studentized residual was used and iteratively removes outliers at the level of three standard deviation. Throughout the pre-qualification and the refining processes, the computation time was significantly improved and the registration accuracy is enhanced. A prototype of the proposed algorithm was implemented and the performance test of 3 Landsat images of Korea. showed: (1) average RMSE error of the approach was 0.435 pixel; (2) the average number of matching points was over 25,573; (3) the average processing time was 4.2 min per image with a regular workstation equipped with a 3 GHz Intel Pentium 4 CPU and 1 Gbytes Ram. The proposed approach achieved robustness, full automation, and time efficiency.

The Development of a Marker Detection Algorithm for Improving a Lighting Environment and Occlusion Problem of an Augmented Reality (증강현실 시스템의 조명환경과 가림현상 문제를 개선한 마커 검출 알고리즘 개발)

  • Lee, Gyeong Ho;Kim, Young Seop
    • Journal of the Semiconductor & Display Technology
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    • v.11 no.1
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    • pp.79-83
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    • 2012
  • We use adaptive method and determine threshold coefficient so that the algorithm could decide a suitable binarization threshold coefficient of the image to detecting a marker; therefore, we solve the light influence on the shadow area and dark region. In order to improve the speed for reducing computation we created Integral Image. The algorithm detects an outline of the image by using canny edge detection for getting damage or obscured markers as it receives the noise removed picture. The strength of the line of the outline is extracted by Hough transform and it extracts the candidate regions corresponding to the coordinates of the corners. Markers extracted using the equation of a straight edge to find the coordinates. By using the equation of straight the algorithm finds the coordinates the corners. of extracted markers. As a result, even if all corners are obscured, the algorithm can find all of them and this was proved through the experiment.

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

  • Liu, Bo;Lin, Yan
    • Ocean Systems Engineering
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    • v.2 no.2
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    • pp.137-145
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    • 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.

Multiresolution Edge Detection Technique (다해상도 에지 검출 기법)

  • 박덕준;박래홍
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.28B no.12
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    • pp.51-58
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    • 1991
  • In this paper, we propose a multiresolution edge detection method which selects the edge detection window size and scale automatically by using the local variance information as an edgeness measure of a region. The mode of the local variance distribution which is calculated over the (2p + 1) x (2p + 1) windows is used to determine the resolution of the given pixel and the edge operator with different scale can be applied to the pixel depending on its resolution. The combination of the resolution determination scheme with the conventional Canny and LOG edge detectors gives the proposed multiresolution edge detection schemes. The effectness of the proposed schemes is shown via computer simulation.

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Road Area Snowfall Intensity Detection from CCD Imagery (CCD 영상을 이용한 도로 강설강도 탐지)

  • Youn, Jun Hee;Kim, Gi Hong;Kim, Tae Hoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.1
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    • pp.89-97
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    • 2013
  • Recently, economic and social damages are globally increased due to the heavy snowfall caused by global warming. To reduce the damages of sudden regional heavy snow in roads, suitable countermeasures should be established based on the accurate detection of snowfall intensity for each roadway segment. In this paper, we deal with snowfall intensity detecting algorithm in the road area from CCD Imagery. First, we determine the MLZ (MotionLess Zone), which does not contain lane markings and moving cars, in the image space. Next, snow streaks trespassing the MLZ are extracted with Canny operator and proposed algorithm. Also, the concept of SII (Snow Intensity Index), which is the number of snow streaks during one minute in the MLZ, is defined. Finally, the effectiveness of proposed algorithm is proved by visually comparing the imagery and SII value obtained during 69 minutes. In consequence, we figured out that the integration of SII is significantly related to an actual amount of snowfall.

Extraction and Revision of Building Information from Single High Resolution Image and Digital Map (단일 고해상도 위성영상과 수치지도로부터 건물 정보 추출 및 갱신)

  • Byun, Young-Gi;Kim, Hye-Jin;Choi, Jae-Wan;Han, You-Kyung;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.2
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    • pp.149-156
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    • 2008
  • In this paper, we propose a method aiming at updating the building information of the digital maps using single high resolution satellite image and digital map. Firstly we produced a digital orthoimage through the automatic co-registration of QuickBird image and 1:1,000 digital map. Secondly we extracted building height information through the template matching of digital map's building vector data and the image's edges obtained by Canny operator. Finally we refined the shape of some buildings by using the result from template matching as the seed polygon of the greedy snake algorithm. In order to evaluate the proposed method's effectiveness, we estimated accuracy of the extracted building information using LiDAR DSM and 1:1,000 digital map. The evaluation results showed the proposed method has a good potential for extraction and revision of building information.