• Journal of Broadcast Engineering
• /
• v.24 no.5
• /
• pp.775-784
• /
• 2019

Image stitching is a technique for solving the problem of narrow field of view of a camera by composing multiple images. Recently, as the use of content such as Panorama, Super Resolution, and 360 VR increases, the need for faster and more accurate image stitching technology is increasing. So far, many algorithms have been proposed to satisfy the required performance, but the objective evaluation method for measuring the accuracy has not been standardized. In this paper, we present the problems of PSNR and SSIM(Structural similarity index method) measurement methods and propose a Local Differential Pixel Mean method. The LDPM evaluation method that includes geometric similarity and brightness measurement information is proved through a test, and the advantages of the evaluation method are revealed through comparison with SSIM.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.3
• /
• pp.806-815
• /
• 1996

The interlaminar fracture behavior of woven laminates under static and cyclic loadings has been studied using DCB(double cantilever beam) specimens. The effects of surface treatment and stiching on the fracture behavior of composite laminates are investigated experimentally. Fracture toughness has been improved by surface treatment because the surface treatment can change the fracture mechanism of laminates. SCB(stitched cantilever beam) model has been proposed to quantify the effect of through-thickness resinforcement(stiching) in improving the delamination crack growth resistance. Distributed loads which are transfered to through-thickness fibers can be calculated by the SCB model. And fracture energy increase due to the distributed load can be predicted by a power function of the distributed load. A new parameter agreed well proposed predict fatigue crack growth rate. The predictions using this parameter agreed well with the experimental data.

• Journal of Broadcast Engineering
• /
• v.25 no.1
• /
• pp.13-24
• /
• 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
• /
• v.23 no.2
• /
• pp.227-234
• /
• 2018

Recently, stitching techniques are used for obtaining wide FOV, e.g., panorama contents, from normal cameras. Despite many proposed algorithms, the no objective quality evaluation method is developed, so the comparison of algorithms are performed only in subjective way. The paper proposes a 'Delaunay-triangulation based objective assessment method' for evaluating the geometric and photometric distortions of stitched or warped images. The reference and target images are segmented by Delaunay-triangulation based on matched points between two images, the average Euclidian distance is used for geometric distortion measure, and the average or histogram of PSNR for photometric measure. We shows preliminary results with several test images and stitching methods for demonstrate the benefits and application.

• The Optical Journal
• /
• s.143
• /
• pp.46-53
• /
• 2013

비구면 광학요소는 광학계에 중요한 이점을 제공하는 반면 정밀한 측정에 제한이 많기에 정밀한 비구면의 생산이 어려운 광학 요소이다. 수년 전 부분 구경 스티칭 방법(Subaperture Stitching Interferometry, 이하 SSI$^{(R)}$)의 개발과 이 기술을 기반으로 하는 장비(SSI-A$^{(R)}$)의 도입으로 비구면 형상오차의 정밀한 측정이 가능하게 되었다. 많은 비구면들이 기존의 SSI-A의 영역에 포함되지만 이에 더 나아가 VONTM(Variable Optical Null)을 도입하면 기존의 측정 영역인 비구면도(best fit sphere에서) $100{\sim}200{\lambda}$대에서 약 $1000{\lambda}$까지 확장하여 측정할 수 있다. 본고에서는 지난 2012년 10월 23일 진행된 QED의 기술강연회에서 발표된 내용 중 VONTM의 원리와 이를 이용한 SSI$^{(R)}$ 기술이 도입된 장치인 ASI$^{(R)}$(Aspheric Stitching Interferometer)의 측정결과를 그 동안 각종 학회 등에서 발표된 자료들을 통하여 소개하도록 하겠다.

• Journal of Mechanical Science and Technology
• /
• v.19 no.2
• /
• pp.567-577
• /
• 2005

Several methods for improving the interlaminar strength and fracture toughness of composite materials are developed. Through-the-thickness stitching is considered one of the most common ways to prevent delamination. Stitching significantly increases the Mode I fracture toughness and moderately improves the Mode II fracture toughness. An analytical model has been developed for simulating the behavior of stitched double cantilever beam specimen under various loading conditions. For z-directional load and moment about the y-axis the numerical solutions are compared with the exact solutions. The derived formulation shows good accuracy when the relative error of displacement and rotation between numerical and exact solution were calculated. Thus we can use the present model with confidence in analyzing other problems involving stitched beams.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.1468-1471
• /
• 2012

It is always a dream to recreate the experience of a particular place, the Panorama Virtual Reality has been interpreted as a kind of technology to create virtual environments and the ability to maneuver angle for and select the path of view in a dynamic scene. In this paper we examined an efficient algorithm for Image registration and stitching of captured imaged from a video stream. Two approaches are studied in this paper. First, dynamic programming is used to spot the ideal key points, match these points to merge adjacent images together, later image blending is use for smooth color transitions. In second approach, FAST and SURF detection are used to find distinct features in the images and a nearest neighbor algorithm is used to match corresponding features, estimate homography with matched key points using RANSAC. The paper also covers the automatically choosing (recognizing, comparing) images to stitching method.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.288-291
• /
• 2003

The technology and performance of the world-largest 54-inch LCD TV using PVA mode have been introduced from two points of view: one is to manufacture large-size panels, the other is to improve electro-optical performance required for multimedia applications. Current ongoing research activities that have been explored include new stitching design, one drop filling with column spacer, response time less than one frame rate, color performance and light efficiency enhancement.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.687-691
• /
• 2000

Diamond turning machines for manufacture of precision optics require deliberate diagnosis to ensure that all the machine elements are properly operating, kinematically, dynamically and thermally, to produce demanded work qualities. One effective way is to directly inspect topographical features of work surfaces that have been carefully generated with prescribed machining conditions intended to exaggerate faulty consequences of any ill-operating machine elements. In this research, a very-large-scale Phase measuring interferometric system that has been developed for years at Korea Advanced Institute of Science and Technology is used to fulfill the metrological requirements fur the surface analysis. A special stitching technique is used to extend the measuring range, which integrates all the patches that are separately sampled over the whole surface while moving the stage. Then, the measured surface profile is analyzed to releated the machine error sources. For this, zernike polynomial fitting is used together with the wavelet filter and the fourier transform. Experimental results showed that the suggested technique in this study is very effective in diagnosing actual diamond turning machines

• Journal of Ocean Engineering and Technology
• /
• v.14 no.2
• /
• pp.89-98
• /
• 2000

Using conventional textile techniques such as weaving braiding knitting and stitching it is possible to produce a wide range two and three dimensional fiber preforms, however so far only a limited attention has been given to knitted fabrics in composite industry. This is mainly due to the opinion that knitted fabric reinforced composites posses low mechanical properties owing to their looped fiber architecture. But it is possible to obtain desired mechanical properties by selecting proper knitted fabric structure, In this paper mechanical characteristics of kevlar plain weft knitted fabrics reinforced plastics(KFRP) are evaluated for th development of intrusion beam of car side door. Tensile bending impact properties of KFRP are measured experimentally and crush demands of Americal Federal Motor Vehicle Safety Standard No.214(FMVSS 214) compared with the bending load and displacement of KFRP by quasi-static test method. The applicability and limitation of bending load and displacement of KFRP according to specimen size has been discussed.