• Title/Summary/Keyword: Corner detector

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DETECTION AND COUNTING OF FLOWERS BASED ON DIGITAL IMAGES USING COMPUTER VISION AND A CONCAVE POINT DETECTION TECHNIQUE

  • PAN ZHAO;BYEONG-CHUN SHIN
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.27 no.1
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    • pp.37-55
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    • 2023
  • In this paper we propose a new algorithm for detecting and counting flowers in a complex background based on digital images. The algorithm mainly includes the following parts: edge contour extraction of flowers, edge contour determination of overlapped flowers and flower counting. We use a contour detection technique in Computer Vision (CV) to extract the edge contours of flowers and propose an improved algorithm with a concave point detection technique to find accurate segmentation for overlapped flowers. In this process, we first use the polygon approximation to smooth edge contours and then adopt the second-order central moments to fit ellipse contours to determine whether edge contours overlap. To obtain accurate segmentation points, we calculate the curvature of each pixel point on the edge contours with an improved Curvature Scale Space (CSS) corner detector. Finally, we successively give three adaptive judgment criteria to detect and count flowers accurately and automatically. Both experimental results and the proposed evaluation indicators reveal that the proposed algorithm is more efficient for flower counting.

A Method to Detect Object of Interest from Satellite Imagery based on MSER(Maximally Stable Extremal Regions) (MSER(Maximally Stable Extremal Regions)기반 위성영상에서의 관심객체 검출기법)

  • Baek, Inhye
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.5
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    • pp.510-516
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    • 2015
  • This paper describes an approach to detect interesting objects using satellite images. This paper focuses on the interesting objects that have common special patterns but do not have identical shapes and sizes. The previous technologies are still insufficient for automatic finding of the interesting objects based on operation of special pattern analysis. In order to overcome the circumstances, this paper proposes a methodology to obtain the special patterns of interesting objects considering their common features and their related characteristics. This paper applies MSER(Maximally Stable Extremal Regions) for the region detection and corner detector in order to extract the features of the interesting object. This paper conducts a case study and obtains the experimental results of the case study, which is efficient in reducing processing time and efforts comparing to the previous manual searching.

Automatic Face Region Detection and Tracking for Robustness in Rotation using the Estimation Function (평가 함수를 사용하여 회전에 강건한 자동 얼굴 영역 검출과 추적)

  • Kim, Ki-Sang;Kim, Gye-Young;Choi, Hyung-Il
    • The Journal of the Korea Contents Association
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    • v.8 no.9
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    • pp.1-9
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    • 2008
  • In this paper, we proposed automatic face detection and tracking which is robustness in rotation. To detect a face image in complicated background and various illuminating conditions, we used face skin color detection. we used Harris corner detector for extract facial feature points. After that, we need to track these feature points. In traditional method, Lucas-Kanade feature tracker doesn't delete useless feature points by occlusion in current scene (face rotation or out of camera). So we proposed the estimation function, which delete useless feature points. The method of delete useless feature points is estimation value at each pyramidal level. When the face was occlusion, we deleted these feature points. This can be robustness to face rotation and out of camera. In experimental results, we assess that using estimation function is better than traditional feature tracker.

Hierarchical Feature Based Block Motion Estimation for Ultrasound Image Sequences (초음파 영상을 위한 계층적 특징점 기반 블록 움직임 추출)

  • Kim, Baek-Sop;Shin, Seong-Chul
    • Journal of KIISE:Software and Applications
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    • v.33 no.4
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    • pp.402-410
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    • 2006
  • This paper presents a method for feature based block motion estimation that uses multi -resolution image sequences to obtain the panoramic images in the continuous ultrasound image sequences. In the conventional block motion estimation method, the centers of motion estimation blocks are set at the predetermined and equally spaced locations. This requires the large blocks to include at least one feature, which inevitably requires long estimation time. In this paper, we propose an adaptive method which locates the center of the motion estimation blocks at the feature points. This make it possible to reduce the block size while keeping the motion estimation accuracy The Harris-Stephen corner detector is used to get the feature points. The comer points tend to group together, which cause the error in the global motion estimation. In order to distribute the feature points as evenly as Possible, the image is firstly divided into regular subregions, and a strongest corner point is selected as a feature in each subregion. The ultrasound Images contain speckle patterns and noise. In order to reduce the noise artifact and reduce the computational time, the proposed method use the multi-resolution image sequences. The first algorithm estimates the motion in the smoothed low resolution image, and the estimated motion is prolongated to the next higher resolution image. By this way the size of search region can be reduced in the higher resolution image. Experiments were performed on three types of ultrasound image sequences. These were shown that the proposed method reduces both the computational time (from 77ms to 44ms) and the displaced frame difference (from 66.02 to 58.08).

Overlay Text Graphic Region Extraction for Video Quality Enhancement Application (비디오 품질 향상 응용을 위한 오버레이 텍스트 그래픽 영역 검출)

  • Lee, Sanghee;Park, Hansung;Ahn, Jungil;On, Youngsang;Jo, Kanghyun
    • Journal of Broadcast Engineering
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    • v.18 no.4
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    • pp.559-571
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    • 2013
  • This paper has presented a few problems when the 2D video superimposed the overlay text was converted to the 3D stereoscopic video. To resolve the problems, it proposes the scenario which the original video is divided into two parts, one is the video only with overlay text graphic region and the other is the video with holes, and then processed respectively. And this paper focuses on research only to detect and extract the overlay text graphic region, which is a first step among the processes in the proposed scenario. To decide whether the overlay text is included or not within a frame, it is used the corner density map based on the Harris corner detector. Following that, the overlay text region is extracted using the hybrid method of color and motion information of the overlay text region. The experiment shows the results of the overlay text region detection and extraction process in a few genre video sequence.

Hybrid Retrieval Machine for Recognizing 3-D Protein Molecules (3차원 단백질 분자 인식을 위한 복합 추출기)

  • Lee, Hang-Chan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.990-995
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    • 2010
  • Harris corner detector is commonly used to detect feature points for recognizing 2-D or 3-D objects. However, the feature points calculated from both of query and target objects need to be same positions to guarantee accurate recognitions. In order to check the positions of calculated feature points, we generate a Huffman tree which is based on adjacent feature values as inputs. However, the structures of two Huffman trees will be same as long as both of a query and targets have same feature values no matter how different their positions are. In this paper, we sort feature values and calculate the Euclidean distances of coordinates between two adjacent feature values. The Huffman Tree is generated with these Euclidean distances. As a result, the information of point locations can be included in the generated Huffman tree. This is the main strategy for accurate recognitions. We call this system as the HRM(Hybrid Retrieval Machine). This system works very well even when artificial random noises are added to original data. HRM can be used to recognize biological data such as proteins, and it will curtail the costs which are required to biological experiments.

Feature Extraction Techniques from Micro Drill Bits Images (마이크로 드릴 비트 영상에서의 특징 추출 기법)

  • Oh, Se-Jun;Kim, Nak-Hyun
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.919-920
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    • 2008
  • In this paper, we present early processing techniques for visual inspection of metallic parts. Since metallic surfaces give rise to specular reflections, it is difficult to extract object boundaries using elementary segmentation techniques such as edge detection or binary thresholding. In this paper, we present two techniques for finding object boundaries on micro bit images. First, we explain a technique for detecting blade boundaries using a directional correlation mask. Second, a line and angle extraction technique based on Harris corner detector and Hough transform is described. These techniques have been effective for detecting blade boundaries, and a number of experimental results are presented using real images.

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Optical Straightness Measuring System Using a Ball-lens (볼렌즈를 이용한 광학식 진직도 측정시스템)

  • Lee, Minho;Cho, Nahm-Gyoo
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.12
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    • pp.1133-1139
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    • 2014
  • This paper proposes a simple method to improve a sensitivity of a straightness measurement system for a linear stage, which is applied to a system based on a geometric optic method. An optical system for this method is composed of a corner-cube retro-reflector, a ball-lens and a twodimensional position sensitive detector (2D PSD). The effectiveness of the proposed method was examined theoretically, and verified experimentally using a prototype measurement system. The results show that the measuring sensitivity was dependent on the size of the ball-lens and the setup position of PSD from the ball-lens, and that the proposed method is efficient method to improve the measuring sensitivity.

Illumination Insensitive Corner Detector Based on Color NTGST (조명 변화에 둔감한 컬러 NTGST기반 코너 검출자)

  • 박기현;서경석;최흥문
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.1775-1778
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    • 2003
  • 본 논문에서는 컬러 NTGST (noise-tolerant generalized symmetry transform)를 기초로 하여 부분적인 조명 변화뿐 아니라 그림자 및 잡음이 있는 환경에서도 효과적으로 코너만을 검출할 수 있는 코너 검출자를 제안하였다. 제안한 코너 검출자는 잡음에 둔감한 NTGST를 기초로 하여 코너에 가까울수록, 두 직선 에지가 이루는 각이 작을수록 큰 값이 코너에 누적되도록 하여 코너의 정확한 위치를 검출할 수 있도록 하였다 특히 조명 변화에 둔감한 HSI 색 공간에서 색상 (hue) 성분을 강조하고 채도 (saturation) 및 휘도 (intensity) 성분을 보조적인 정보로 활용함으로써 부분적인 조명 및 그림자의 영향을 줄일 수 있도록 가중조합 벡터 미분 연산자 (weighted combination of vector gradient vector operator)를 제안 적용하여 그림자로 인한 거짓 경계선 및 거짓 코너를 제거할 수 있도록 하였다. 실험을 통하여 제안한 코너 검출 방법이 잡음 및 조명 변화에 둔감하게 효과적으로 코너를 검출함을 확인하였다.

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Vision-Based Indoor Localization Using Artificial Landmarks and Natural Features on the Ceiling with Optical Flow and a Kalman Filter

  • Rusdinar, Angga;Kim, Sungshin
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.13 no.2
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    • pp.133-139
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    • 2013
  • This paper proposes a vision-based indoor localization method for autonomous vehicles. A single upward-facing digital camera was mounted on an autonomous vehicle and used as a vision sensor to identify artificial landmarks and any natural corner features. An interest point detector was used to find the natural features. Using an optical flow detection algorithm, information related to the direction and vehicle translation was defined. This information was used to track the vehicle movements. Random noise related to uneven light disrupted the calculation of the vehicle translation. Thus, to estimate the vehicle translation, a Kalman filter was used to calculate the vehicle position. These algorithms were tested on a vehicle in a real environment. The image processing method could recognize the landmarks precisely, while the Kalman filter algorithm could estimate the vehicle's position accurately. The experimental results confirmed that the proposed approaches can be implemented in practical situations.