• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.98-103
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• 2005

The Flight Model of MAC (Medium-sized Aperture Camera), a 2.5m GSD class earth observation camera has been aligned and assembled. Topics discussed in this paper include the ground MTF performance of the MAC system, and the alignment of the focal plane assembly. MTF was measured by a knife-edge scanning technique, and a 450 mm diameter Cassegrain collimator with diffraction-limited performance was made and used for the MTF measurements. System MTF was used as the figure-of-merit to find the best focus of the focal plane assembly.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.6
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• pp.464-468
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• 2009

In this paper we propose an image-based approach, which is different from the traditional flow cytometric method to detect shape of apoptosis cells. This method can overcome the defects of cytometry and give precise recognition of apoptosis cells. In this work K-means clustering was used to do the rough segmentation and an active contour model, called 'snake' was used to do the precise edge detection. And then some features were extracted including physical feature, shape descriptor and texture features of the apoptosis cells. Finally a Mahalanobis distance classifier classifies the segmentation images as apoptosis and non-apoptosis cell.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.6 s.312
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• pp.26-33
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• 2006

Film restoration is to detect the location and extent of defected regions from a given movie film, and if present, to reconstruct the lost information of each region. It has gained increasing attention by many researchers, to support multimedia service of high quality. In general, an old film is degraded by dust, scratch, flick, and so on. Among these, the most frequent degradation is the scratch. So far techniques for the scratch restoration have been developed, but they have limited applicability when dealing with all kinds of scratches. To fully support the automatic scratch restoration, the system should be developed that can detect all kinds of scratches from a given frame of old films. This paper presents a neurual network (NN)-based texture classifier that automatically detect all kinds of scratches from frames in old films. To facilitate the detection of various scratch sizes, we use a pyramid of images generated from original frames by having the resolution at three levels. The image at each level is scanned by the NN-based classifier, which divides the input image into scratch regions and non-scratch regions. Then, to reduce the computational cost, the NN-based classifier is only applied to the edge pixels. To assess the validity of the proposed method, the experiments have been performed on old films and animations with all kinds of scratches, then the results show the effectiveness of the proposed method.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.163-166
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• 2004

본 논문은 3차원 형상 인식시스템으로부터 스캔 한 3차일 영상 데이터의 깊이정보에 3차원 에지를 추출하여 워터마크를 삽입하는 알고리즘을 제안한다. 제안한 알고리즘에서는 3차원 수직 평형 형상 인식기로 object scanning을 한 데이터 값들을 추출한다. 이 추출된 값들의 특성은 2차원 영상 즉 x, y축에 각각의 픽셀에 깊이정보를 가지는 3차원영상으로서 기존의 3차원영상과는 다른 차이를 가지며 영상의 품질이 우수하며 많은vertex 정보와 메쉬 정보를 가지고 있다. 따라서 획득된 데이터에서 x좌표와 y좌표는 영상에 있어서 위치를 나타내는 정보이고, T좌표는 3차원영상을 형성하는 깊이 정보들이다. 3차원 형상 인식시스템에서 스캔 한 3차원 얼굴영상으로부터 에지를 검출하여 에지가 존재하는 위치에 워터마크를 삽입하는 알고리즘을 제안하였다. 본 논문에서 제안한 워터마킹 알고리즘의 성능 평가를 위한 모의실험 한 결과 워터마크가 삽입된 모텔의 절단(cropping), 리메쉬(remesh) 및 메쉬간소화(mesh simplification) 공격에 대한 견고성이 우수함을 확인함으로써 3차원형상 인식 시스템에 직접적인 워터마크 삽입이 가능함을 증명하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.648-649
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• 2022

Glass is a common object in living environments, but even humans are sometimes unable to identify it. This study proposes a method for detecting glass area by learning edge information from images. The network structure of Transformer is used to accept the base features extracted by backbone and extract the boundary information of RGB images, and both features are used to learn the features of glass area and determine the glass area based on these boundary features. The experimental results show that our proposed method can detect glass area in images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.4
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• pp.55-62
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• 2007

This paper proposes a defective pixel detection algorithm and its hardware structure for CCD/CMOS image sensor. In previous algorithms, the characteristics of image have not been considered. Also, some algorithms need quite a time to detect defective pixels. In order to make up for those disadvantages, the proposed defective pixel detection method detects defective pixels efficiently by considering the edges in the image and verifies them using several frames while checking scene-changes. Whenever scene-change is occurred, potentially defective pixels are checked and confirmed whether it is defective or not. Test results showed that the correct detection rate in a frame was increased 6% and the defective pixel verification time was decreased 60%. The proposed algorithm was implemented with verilog HDL. The edge indicator in color interpolation block was reused. Total logic gate count was 5.4k using 0.25um CMOS standard cell library.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.416-419
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• 2003

The cellular neural networks have the circuit structure that differs from the form of general neural network. It consists of an array of the same cell which is a simple processing element, and each of the cells has local connectivity and space invariant template property. In this paper, time-multiplex image processing technique is applied for processing large images using small size CNN cell block, and we simulate the edge detection of a large image using the simulator implemented with a c program and matlab model. A 5$\times$5 CNN hardware and pre post processor is also implemented and is under test.

• Journal of Korea Multimedia Society
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• v.16 no.6
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• pp.756-763
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• 2013

Bilateral filter (BF), functioning by two Gaussian filters, domain and range filter is a nonlinear filter for sharpness enhancement and noise removal. In infrared (IR) small target detection field, the BF is designed by background predictor for predicting background not including small target. For this, the standard deviations of the two Gaussian filters need to be changed adaptively in background and target region of an infrared image. In this paper, the proposed bilateral filter make the standard deviations changed adaptively, using variance feature of mean values of surrounding block neighboring local filter window. And, in case the variance of mean values for surrounding blocks is low for any processed pixel, the pixel is classified to flat background and target region for enhancing background prediction. On the other hand, any pixel with high variance for surrounding blocks is classified to edge region. Small target can be detected by subtracting predicted background from original image. In experimental results, we confirmed that the proposed bilateral filter has superior target detection rate, compared with existing methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.262-270
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• 2008

We propose a technique to protect digital images using the magnitude and orientation of their edges. The proposed technique uses the content-associated copyright message generated by combining the original copyright message with the magnitude and orientation of some edges of a digital image. It enables the distribution of the original copyright message without any distortion of original digital images by avoiding embedment of the original copyright message into images. In addition to the advantage in the image quality, it also has a relatively low computational complexity by using simple operations to generate the content-associated copyright message. To verify the proposed technique, we performed experiments on its robustness to the external attacks such as histogram equalization, median filtering, rotation, and cropping. Experimental results on restoring the copyright message from images distorted by attacks show that more than 90%, on the average, can be recovered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.187-192
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• 2021

This study proposes a system for take-off in a forest or similar complex environment using an object detector. In the simulator, a raspberry pi is mounted on a quadcopter with a length of 550mm between motors on a diagonal line, and the experiment is conducted based on edge computing. As for the images to be used for learning, about 150 images of 640⁎480 size were obtained by selecting three points inside Kunsan University, and then converting them to black and white, and pre-processing the binarization by placing a boundary value of 127. After that, we trained the SSD_Inception model. In the simulation, as a result of the experiment of taking off the drone through the model trained with the verification image as an input, a trajectory similar to the takeoff was drawn using the label.