• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.39-46
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• 2013

Recently, the mobile industries grow up rapidly and their performances are improved. So the usage of mobile devices is increasing in our life. Also mobile devices equipped with a high-performance camera, so the image stitching can carry out on the mobile devices instead of the desktop. However the mobile devices have limited hardware to perform the image stitching which has a lot of computational complexity. In this paper, we have proposed improved feature descriptor extraction and matching method for efficient image stitching on mobile environment. Our method can reduce computational complexity using extension of orientation window and reduction of dimension feature descriptor when feature descriptor is generated. In addition, the computational complexity of image stitching is reduced through the classification of matching points. In our results, our method makes to improve the computational time of image stitching than the previous method. Therefore our method is suitable for the mobile environment and also that method can make natural-looking stitched image.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.30-42
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• 2022

Due to the increase in construction of tunnels, the burdens of maintenance works for tunnel structures have been increasing in Korea. In addition, the increase of traffic volume and aging of materials also threatens the safety of tunnel facilities, therefore, maintenance costs are expected to increase significantly in the future. Accordingly, automated condition assessment technologies like image-based tunnel scanning system for inspection and diagnosis of tunnel facilities have been proposed. For image-based tunnel scanning system, it is key to create a planar image through stitching of multiple images captured by tunnel scanning system. In this study, performance of feature-based stitching algorithms suitable for stitching tunnel scanning images was evaluated. In order to find a suitable algorithm SIFT, ORB, and BRISK are compared. The performance of the proposed algorithm was determined by the number of feature extraction, calculation speed, accuracy of feature matching, and image stitching result. As for stitching performance, SIFT algorithm was the best in all parts of tunnel image. ORB and BRISK also showed satisfactory performance and short calculation time. SIFT can be used to generate precise planar images. ORB and BRISK also showed satisfactory stitching results, confirming the possibility of being used when real-time stitching is required.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.363-365
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• 2017

The telescope to be onboard SPICA (Space Infrared Telescope for Cosmology and Astrophysics) has an aperture diameter of 2.5 m and its imaging performance is to be diffraction-limited at a wavelength of $20{\mu}m$ at the operating temperature of <8 K. Because manufacturing precise autocollimating flat mirrors (ACFs) with sizes comparable to the SPICA telescope is not technically feasible, we plan to use sub-aperture stitching interferometry through ACFs for optical testing of the telescope. We have verified the applicability of the sub-aperture stitching technique to the SPICA telescope by performing stitching experiments in a vacuum at a room temperature, using the 800-mm telescope and a 300-mm ACF. We have also developed a new method to reduce uncertainties possibly caused by cryogenic and gravitational deformations of ACFs.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.84-87
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• 2015

For large optical elements which are tested by many sub-apertures, it takes too much time for a sub-aperture stitching algorithm to get the stitching result. To solve this problem, we propose a fast sub-aperture stitching algorithm to quickly compensate for piston, tilt, and defocus errors. Moreover, the new algorithm is easy to understand and program. We use partial derivatives of measurement data to separately solve piston, tilt, and defocus errors. First, we show that the new algorithm has a lower time complexity than the currently used algorithm. Although simulation results indicate that the accuracy of the new algorithm is lower than the current algorithm in all 20 simulations, our experimental results validate the algorithm and show it is sufficiently accurate for general use.

• Journal of IKEEE
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• v.20 no.4
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• pp.420-423
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• 2016

In this paper, we proposed an implementation of panoramic image stitching that operates in real time at the embedded environment by applying ROI based PROSAC algorithm using the directionality of the image. The conventional panoramic image stitching applies SURF or SIFT algorithm which contains unnecessary computation and a lots of data to detect feature points. In this paper, we use the direction of the input image and we proposed the method of reducing the unnecessary computation by using ROI. We use a gyro sensor and an acceleration sensor. Output data from gyro and acceleration sensors can be calibrated by complementary filter. The calibration does not affect the operating time of the proposed image stitching algorithm in embedded environment. Therefore, it is possible to operate in real-time.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.31-34
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process has been utilized for providing through-thickness reinforcements. 2D prefonl1S were stacked with S-2 glass plain weave, and 3D preforms were fabricated using the stitching process. For the matrix system, epoxy and phenol resins were considered. To examine the damage resistance performance the low velocity drop weight impact test has been carried out, and the impact damage was examined by scanning image. CAI (Compressive After Ih1paet) tests were also conducted to evaluate residual compressive strength. Compared with 2D epoxy composites, 2D phenol composites showed drastic reduction in the compressive strength prior to impact because of the higher contents of voids. The damage area of 2D phenol composites were also larger than that of 2D epoxy composites. However, by introducing the stitching, the damage area of 3D phenol composites was reduced by 60%, while the CAI strength improvement was negligible.

• Korean Journal of Human Ecology
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• v.13 no.1
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• pp.145-152
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• 2004

The purpose of this study was to find out the traditional decoration techniques in the Korean costume. Both quantitative and qualitative research methods were used to collect and investigated the traditional decoration techniques used in the related literatures and museum catalogues. The results were as follows. The broad and back stitching are fundamental stitching, which used to Nubi and Keki. Top stitching applied broadly to the Korean costume, for example, Jergori, Wonsam, Jeonbok, Beosun, Bojagj and so on. The expression techniques for top stitching were one, two or three stitches. When the top stitching was used as colorful stitches, they were more decorative. The Zatmulim was used for the decorative effect on the seam line because it was triangular shaped and became more effective by changing the rotor and size. Sunmulim was used on the narrow line such as the seam lines of Gergori and Chima. The bakchi decoration was imitating a bat shape, had a meaning of bringing the goodness and gave the tiny and elaborated image. It was used to the neckline of Geogori, seam line of Chima, Pungcha Bazi and so on. Sattgi was used to attaching the bottom of two stiff fabrics adopting for Beosun, Ayam and Norigae. When it used colorful strings, the more decorative effect was added. The knot for button used the fabric instead of buttons and applied to the Cheonlik, Gergori. The aesthetic values of the traditional decoration techniques in the costume were both natural beauty and practicality with creativity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1777-1784
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• 2000

In this paper we suggested the chirp stitching algorithm and transmitter/receiver channel to a spaceborne high resolution SAR which enables wideband signal generation and processing with minimum hardware requirement. The transmitter channel generates two sub-band signals and then generate a wideband signal using chirp stitching algorithm and the receiver channel divides a wideband signal into two sub-band signals in order to overcome the high speed data handling capability of this spaceborne systems. We generated and processed a 100 MHz wideband signal evaluated the performance and verified the feasibility of the application of this chirp stitching algorithm and transmitter/receiver channel to spaceborne high resoultion SAR.

• Macromolecular Research
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• v.11 no.2
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• pp.98-103
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• 2003

The mechanical properties and failure mechanisms of through-the-thickness stitched plain weave glass fabric/polyurethane foam/epoxy composites were studied. Hybrid composites were fabricated using resin infusion process (RIP). Stitched sandwich composite increased drastically the flexural properties as compared with the unstitched fabrics. The breaking of stitching yarns was observed during the flexural test and this failure mode yielded relatively high flexural properties. Composites with stitched sandwich structure improved the mechanical properties with increasing the number of stitching yarns. From this study, it was concluded that proper combination of stitching density and types of stitching fiber is important factor for through-the-thickness stitched composite panels.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.97-102
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• 2016

Image stitching is a process of combining two or more images with overlapping area to create a panorama of input images, which is considered as an active research area in computer vision, especially in the field of augmented reality with 360 degree images. Image stitching techniques can be categorized into two general approaches: direct and feature based techniques. Direct techniques compare all the pixel intensities of the images with each other, while feature based approaches aim to determine a relationship between the images through distinct features extracted from the images. This paper proposes a novel image stitching method based on feature pixels with approximated clustering filter. When the features are extracted from input images, we calculate a meaning of the minutiae, and apply an effective feature extraction algorithm to improve the processing time. With the evaluation of the results, the proposed method is corresponding accurate and effective, compared to the previous approaches.