• 대한전자공학회논문지
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• 제25권5호
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• pp.550-558
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• 1988

This paper presents laplacian pyramid vector quantization (LPVQ) approach in which a vector quantizer is used to encode a series of quasi-bandpassed images generated by the laplacian pyramid processing. Performance of the LPVQ is compared to those of DCT domain methods at the same bit rate via computer simulations. Experimental results show that the PSNR's (peak signal-to-noise ratio) for the LPVQ are almost the same as those of the DCT based methods. However, subjective study indicates the LPVQ obtains slightly higher scores than the DCT based techniques.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1347-1351
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• 1987

This thesis aims at studying laplacian pyramid vector quantization which keeps a simple compression algorithm and stability against various kinds of image data. To this end, images are devied into two groups according to their statistical characteristics. At 0.860 bits/pixel and 0.360 bits/pixel respectively, laplacian pyramid vector quantization is compared to the existing spatial domain vector quantization and transform coding under the same condition in both objective and subjective value. The laplacian pyramid vector quantization is much more stable against the statistical characteristics of images than the existing vector quantization and transform coding.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.117-122
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• 2002

Electrical discharge machining uses thermal energy from electrical discharge, while wire electrical discharge machining (WEDM) technology is widely used in conductive material machining. This paper proposes a method for evaluating the characteristics of wires in WEDM. In order to evaluate the wire processing performance, processing speed and roughness, straightness, corner processing have been assessed with precision experiment equipment and image processing including Laplacian filtering with various threshold levels.

• 반도체디스플레이기술학회지
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• 제15권3호
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• pp.51-56
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• 2016

This paper proposes a new image enhancement method for an infrared thermal image. The proposed method uses both Laplacian and Prewitt edge detectors. Without a visible light, it uses an infrared image for the edge detection. The method subtracts contour images from the infrared thermal image. It results black contours of objects in the infrared thermal image. That makes the objects in the infrared thermal image distinguished clearly. The proposed method is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiments were conducted by using various infrared thermal images. The results show that the proposed method is successful for image enhancement of an infrared thermal image.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.787-789
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• 2017

에지 검출은 이미지 분석, 패턴 인식 및 컴퓨터 비전과 같은 많은 응용분야에서 사용되고 있다. 기존의 에지 검출 방법들에는 Sobel, Prewitt, Roberts, LoG(Laplacian of Gaussian)등이 존재한다. 기존 에지 검출 방법은 원영상이 저조도일 경우 화소 휘도의 변화가 적기 때문에 에지 검출이 미흡하다. 따라서 본 논문에서는 이러한 문제점을 해결하기 위해 저조도 영상의 화소 휘도를 변환하는 함수를 제안하였다. 그리고 화소 휘도 변환 함수의 성능을 확인하기 위해 기존의 방법 Sobel, Prewitt, Roberts, LoG(Laplacian of Gaussian)에 적용하여 비교 분석하였다.

• 한국정보통신학회논문지
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• 제18권8호
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• pp.1973-1980
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• 2014

영상, 차선, 물체 인식 등을 위한 에지 검출은 중요한 영상 처리 방법이며, 이를 위한 기존의 방법에는 Sobel, Prewitt, Roberts, Laplacian, LoG(Laplacian of Gaussian) 등이 있다. 이러한 방법들은 salt & pepper 잡음에 훼손된 영상에서 특성이 미흡하다. 이와 같은 문제점을 개선하기 위하여 본 논문에서는 중심 화소의 인접 화소를 중심으로 국부 마스크를 설정하여, 그것의 중심 화소가 비잡음인 경우 그대로 처리하고 잡음인 경우 추정 마스크를 구한 후, 가중치 마스크를 적용하여 에지를 검출하는 알고리즘을 제안하였다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.199-204
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• 2007

In digital radiography, to improve the contrast of digital radiography image, the multi-scale nonlinear amplification algorithm based on unsharp masking is one of the major image enhancement algorithms. In this paper, we used the Laplacian pyramid to decompose a digital radiography(DR) image. In our simulation, the DR image was decomposed into seven layers and the coefficients of the each layer was amplified with nonlinear function. We also imported a noise containment algorithm to limit noise amplification. To enhance the contrast of image, we proposed a new adaptive non-linear gain amplification coefficients. As a result of having applied to some clinical data, a detail visibility was improved significantly without unacceptable noise boosting. Images that acquired with the proposed adaptive non-linear gain coefficients have shown superior quality to those that applied similar gain control method and expected to be accepted in the clinical applications.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.100-103
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• 2014

현재 에지 검출은 여러 분야에서 사용되고 있으며, 대부분의 영상처리의 전처리 과정 및 영상처리에 있어서 필수불가결한 기술이다. 이에 따라 관련 연구가 끊임없이 진행되어 오고 있다. 이러한 에지는 영상의 물체에 대한 크기, 방향, 위치 등의 중요한 영상 요소를 가지고 있다. 이를 검출하기 위한 여러 방법들이 제안되어 왔으며, 그 중 대표적인 방법은 Sobel, Prewitt, Roberts, Laplacian, LoG(Laplacian of Gaussian) 등이 있다. 그러나 이러한 기존의 방법들은 복합잡음이 첨가된 영상에서 에지 검출 특성이 미흡하다. 따라서 본 연구에서는 국부 마스크의 크기와 위치에 따라 요소에 대한 중앙값 및 평균값을 이용한 에지 검출 방법을 제안하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.911-914
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• 1998

In this paper, the importance of including small image features at the initial levels of a progressive second generation video coding scheme is presented. It is shown that a number of meaningful small features called details shouuld be coded in order to match their perceptual significance to the human visual system. We propose a method for extracting, perceptually selecting and coding of visual details in a video sequence using morphological laplacian operator and modified post-it transform is very efficient for improving quality of the reconstructed images.

• Journal of information and communication convergence engineering
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• 제13권4호
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• pp.264-269
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• 2015

The chest X-ray image cannot be focused in the same manner that optical lenses are and the resultant image generally tends to be slightly blurred. Therefore, the methods to improve the quality of chest X-ray image have been studied. In this paper, the inherent noises of the input images are suppressed by adding the Laplacian image to the original. First, the chest X-ray image using an Gaussian high pass filter and an optimal high frequency emphasis filter has shown improvements in the edges and contrast of flat areas. Second, using fuzzy logic_histogram equalization, each pixel of the chest X-ray image shows the normal distribution of intensities that are not overexposed. As a result, the proposed method has shown the enhanced edge and contrast of the images with the noise canceling effect.