• Journal of Broadcast Engineering
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• v.25 no.6
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• pp.1004-1012
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• 2020

We present a novel content-preserving seam estimation algorithm for real-time high-resolution video stitching. Seam estimation is one of the fundamental steps in image/video stitching. It is to minimize visual artifacts in the transition areas between images. Typical seam estimation algorithms are based on optimization methods that demand intensive computations and large memory. The algorithms, however, often fail to avoid objects and results in cropped or duplicated objects. They also lack temporal consistency and induce flickering between frames. Hence, we propose an efficient and temporarily-consistent seam estimation algorithm that utilizes a straight line. The proposed method also uses convolutional neural network-based instance segmentation to locate seam at out-of-objects. Experimental results demonstrate that the proposed method produces visually plausible stitched videos with minimal visual artifacts in real-time.

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.808-816
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• 2017

360 VR video systems has become important to provide immersive effect for viewers. The system consists of stitching, projection, compression, inverse projection, viewport extraction. In this paper, an efficient luminance compensation technique for 360 VR video sequences, where feature extraction and histogram equalization algorithms are utilized. The proposed luminance compensation algorithm enhance the performance of stitching in 360 VR system. The simulation results showed that the proposed technique is useful to increase the quality of the displayed image.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3538-3556
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• 2014

This paper proposes a novel video stitching method that improves real-time performance and visual quality of a multi-camera video surveillance system. A two-stage seam searching algorithm based on enhanced dynamic programming is proposed. It can obtain satisfactory result and achieve better real-time performance than traditional seam-searching methods. The experiments show that the computing time is reduced by 66.4% using the proposed algorithm compared with enhanced dynamic programming, while the seam-searching accuracy is maintained. A real-time local update scheme reduces the deformation effect caused by moving objects passing through the seam, and a seam-based local color transfer model is constructed and applied to achieve smooth transition in the overlapped area, and overcome the traditional pixel blending methods. The effectiveness of the proposed method is proved in the experiements.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.279-281
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• 2020

본 논문은 고정되지 않고 흔들리는 영상을 각 프레임마다 이미지 스티칭(Image Stitching)으로 비디오를 구성하였을 때 생기는 영상이 심하게 흔들리는 문제 등을 보완하기 위해 새로운 비디오 스티칭(Video Stitching) 방법을 제안한다. NISwGSP 알고 리즘으로 각 프레임 이미지를 스티칭하고 스티칭 형태를 어느 정도 유지시켜주는 새로운 코스트 함수를 도입하여 스티칭 영상의 흔들림 문제를 해결한다. 메쉬(Mesh) 기반 이미지 스티칭 알고리즘인 NISwGSP를 써서 비디오 스티칭을 할 때 메쉬의 버텍스(Vertices)를 이전 프레임의 버텍스로 유지하도록 하여 스티칭 형태를 고정시키는 것이 본 논문에서 제시하는 방법이다.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.27-38
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• 2017

This Paper Presents a Method for Stitching a Large Number of Images Recorded by a Large Number of Individual Users Through a Cellular Phone Camera at a Venue. In Contrast to 360 Camera Solutions that Use Existing Fixed Rigs, these Conditions must Address New Challenges Such as Time Synchronization, Repeated Transformation Matrix Calculations, and Camera Sensor Mismatch Correction. In this Paper, we Solve this Problem by Updating the Transformation Matrix Using Time Synchronization Method Using Audio, Sensor Mismatch Removal by Color Transfer Method, and Global Operation Stabilization Algorithm. Experimental Results Show that the Proposed Algorithm Shows better Performance in Terms of Computation Speed and Subjective Image Quality than that of Screen Stitching.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.204-206
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• 2017

최근에 개인용 카메라를 통해 개인의 추억을 파노라마 영상으로 기록하는 것에 관심이 급증하고 있다. 파노라마 영상에 관심이 급증함에 따라 파노라마 영상을 제작하는 방법에 대해 여러 분야에서 연구가 많이 진행되고 있다. 일반적으로 개인용 카메라를 손으로 잡고 촬영하는 경우가 대부분이다. 손으로 잡고 촬영한 영상은 손 떨림에 의해 흔들린 영상이 된다. 이는 파노라마 영상을 만들 때 어려운 요소를 야기한다. 그러므로 흔들린 영상을 정합하고 안정화하는 연구는 매우 중요하다. 따라서 본 연구의 목적은 최근에 연구된 비디오 정합(Video Stitching)과 비디오 안정화(Video Stabilization)의 정확도 및 경향을 파악을 통해 빛의 변화가 빈번하고 움직임이 많은 콘서트 영상 정합에 이용될 아이디어 추출에 있다.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1329-1336
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• 2016

This paper develops a 360 degree video system using multiple off-the-shelf webcams and a set of embedded boards. Existing 360 degree cameras have shortcomings that they do not support real-time video generation since recorded videos should be copied to computers or smartphones which then provide stitching. Another shortcoming is that wide FoV(Field of View) cameras are not able to provide sufficiently high resolution. Moreover, resulting images are visually distorted bending straight lines. By employing an array of 65 degree FoV webcams, we were able to generate videos on the spot and achieve over 6K resolution with much less distortion. We describe the configuration and algorithms of the proposed system. The performance evaluation results of our early stage prototype system are presented.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.13-24
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• 2020

There are about nine million power line poles and 1.3 million kilometers of the power line for electric power distribution in Korea. Maintenance of such a large number of electric power facilities requires a lot of manpower and time. Recently, various fault diagnosis techniques using artificial intelligence have been studied. Therefore, in this paper, proposes a power line deflection detect system using artificial intelligence and computer vision technology in images taken by vision system. The proposed system proceeds as follows. (i) Detection of transmission tower using object detection system (ii) Histogram equalization technique to solve the degradation in image quality problem of video data (iii) In general, since the distance between two transmission towers is long, a panoramic video stitching process is performed to grasp the entire power line (iv) Detecting deflection using computer vision technology after applying power line detection algorithm This paper explain and experiment about each process.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.366-374
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• 2017

Since a display device such as TV or digital signage is getting larger, the types of media is getting changed into wider view one such as UHD, panoramic and jigsaw-like media. Especially, panoramic and jigsaw-like media is realized by stitching video clips, which are captured by different camera or devices. However, a stitching process takes long time, and has difficulties in applying for a real-time process. Thus, this paper suggests to find out 2D Adjacency Matrix, which tells spatial relationships among those video clips in order to decrease a stitching processing time. Using the Discrete Cosine Transform (DCT), we convert the each frame of video source from the spatial domain (2D) into frequency domain. Based on the aforementioned features, 2D Adjacency Matrix of images could be found that we can efficiently make the spatial map of the images by using DCT. This paper proposes a new method of generating 2D adjacency matrix by using DCT for producing a panoramic and jigsaw-like media through various individual video clips.

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.817-828
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• 2017

In this paper, we propose an efficient stabilization algorithm for 360 VR sequence, where the geometric information and the relationship between various projection formats have been utilized. The proposed scheme consists of '1st stitching', 'extraction of wide angle picture from VR data', 'stabilization', and '2nd stitching'. The simulation results show that the proposed method outperforms the conventional algorithms in the viewpoint of image quality for end-user.