• 한국공작기계학회논문집
• /
• 제10권5호
• /
• pp.1-8
• /
• 2001

A measuring system is developed to acquire static image from rotary state through CCD camera in back light illumination by synchronizing chopper to workpiece. In image processing of acquired image, lowpass filter is very useful in view of noise removal, and optimum binary image can be made through histogram equalization which is one of the histogram technique to maximize brightness intensity between workpiece and background. After image treatment applying Laplacian operator, surface roughness is calculated by introducing conversion coefficient of pixel which edge is composed of.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.472-472
• /
• 2010

The tomography has played a key role in tokamak plasma diagnostics for image reconstruction. The Phillips-Tikhonov (P-T) regularization method was attempted in this work to reconstruct cross-sectional phantom images of the plasma by minimizing the gradient between adjacent pixel data. Recent studies about the comparison of the several tomographic reconstruction methods showed that the P-T method produced more accurate results. We have studied existing Laplacian matrix used in Phillips-Tikhonov regularization method and developed modified Laplacian matrix (Modified L). The comparison of the reconstruction result by the modified L and existing L showed that modified L produced more accurate result. The difference was significantly pronounced when a portion of plasma was reconstructed. These results can be utilized in the Edge Plasma diagnostics; especially in divertor diagnostics on tokamak a large impact is expected. In addition, accurate reconstruction results from received data in only one direction were confirmed through phantom test by using P-T method with modified L. These results can be applied to the tangentially viewing pin-hole camera diagnostics on tokamak.

• 대한의용생체공학회:의공학회지
• /
• 제37권4호
• /
• pp.140-146
• /
• 2016

The ultrasound imaging in medical diagnosis has become a popular modality because of its safe, noninvasive, portable, relatively inexpensive, and provides a real-time image formation. However, usefulness of ultrasound imaging is at times limited due to the presence of signal-dependent noise like as speckle. Therefore, noise reduction is very important, as various types of noise generated limits the effectiveness of medical image diagnosis. This paper introduces a speckle noise reduce algorithm using total variation denoising (TVD) in Laplacian pyramid. With this method, speckle is removed by TVD of bandpass ultrasound images in Laplacian pyramid domain. For TVD in each pyramid layer, a ${\lambda}$ is selected by trial-and-error method. The visual comparison of despeckled 'in vivo' ultrasound images from pancreas shows that the proposed method could effectively preserve edges and detailed structures while thoroughly suppressing speckle. For a Simulated B-mode image, contrast-to-noise-ratio (CNR) and signal-to-noise-ratio (SNR) were obtained like 4.65 dB and 14.11 dB, respectively. The results show that the proposed method can conduct better than some of the existing methods in terms of the CNR and the SNR.

• 한국정보통신학회논문지
• /
• 제19권10호
• /
• pp.2441-2449
• /
• 2015

디지털 정보화 시대에서 영상은 여러 매체에서 필수적으로 이용되며, 에지는 영상에서 물체의 크기, 위치, 방향 등을 포함하는 중요한 특징 정보이다. 이러한 에지를 검출하기 위한 여러 연구들이 국내외에서 진행되고 있다. 기존의 에지 검출 방법들에는 고정된 가중치 값을 적용하는 Sobel, Prewitt, Roberts, Laplacian, LoG 등이 있다. 이와 같은 기존의 에지 검출 방법들은 고정된 가중치 마스크를 영상에 적용하기 때문에 에지 검출 특성이 다소 미흡하게 나타난다. 따라서 본 연구에서는 이러한 문제점을 보완하기 위해, 모폴로지에서 bottom-hat 변환과 열기 연산을 이용하여 영상을 개선하고 마스크 기반의 기울기를 구한 후 에지를 구하는 알고리즘을 제안하였다. 그리고 제안한 알고리즘의 성능을 평가하기 위해, 기존의 Sobel, Roberts, Prewitt, Laplacian, LoG 에지 검출 방법들과 비교하여 시각적 영상을 나타내었고, 각각의 영상을 기준으로 하는 MSE 값을 구하여 유사성을 비교하였다.

• 한국통신학회논문지
• /
• 제12권4호
• /
• pp.405-413
• /
• 1987

본 논문은 2-차원에서 3가지 형태(Square, Cross, X-shape)의 메디안 필터를 사용하여 레이다 영상의 원영상을 유지하면서 잡음을 제거하여 영상을 개선하고, 연산자를 적용하여 경계를 검출한다. 레이다 영상의 특성에서 곡선 부분이 많으므로 제안된 경계 검출 연산자에 의한 결과와 기존의 경계검출 방법인 Sobel, Prewitt, Robert, Laplacian. Kirsch의 결과를 비교한다.

• Journal of Information Processing Systems
• /
• 제16권6호
• /
• pp.1479-1494
• /
• 2020

As an important part of image processing, image demosaicking has been widely researched. It is especially necessary to propose an efficient interpolation algorithm with good visual quality and performance. To improve the limitations of residual interpolation (RI), based on RI algorithm, minimalized-Laplacian RI (MLRI), and iterative RI (IRI), this paper focuses on adaptive RI (ARI) and proposes an improved ARI (IARI) algorithm which obtains more distinct R, G, and B colors in the images. The proposed scheme fully considers the brightness information and edge information of the image. Since the ARI algorithm is not completely adaptive, IARI algorithm executes ARI algorithm twice on R and B components according to the directional difference, which surely achieves an adaptive algorithm for all color components. Experimental results show that the improved method has better performance than other four existing methods both in subjective assessment and objective assessment, especially in the complex edge area and color brightness recovery.

• Journal of applied mathematics & informatics
• /
• 제41권5호
• /
• pp.1115-1128
• /
• 2023

In this paper, a novel hybrid method for multi-focus image fusion is proposed. The method combines the advantages of wavelet transform-based methods and focus-measure-based methods to achieve an improved fusion result. The input images are first decomposed into different frequency sub-bands using the discrete wavelet transform (DWT). The focus measure of each sub-band is then calculated using the Laplacian of Gaussian (LoG) operator, and the sub-band with the highest focus measure is selected as the focused sub-band. The focused sub-band is sharpened using an unsharp masking filter to preserve the details in the focused part of the image.Finally, the sharpened focused sub-bands from all input images are fused using the maximum intensity fusion method to preserve the important information from all focus images. The proposed method has been evaluated using standard multi focus image fusion datasets and has shown promising results compared to existing methods.

• 전기학회논문지
• /
• 제59권3호
• /
• pp.651-656
• /
• 2010

This paper proposes a new dynamic PCA algorithm to recognize types of electric poles, which is necessary for a mobile robot moving along the neutral line for inspecting high-voltage facilities. Since the mobile robot needs to pass over the electric poles and grasp the neutral wire again for the next region inspection, the detection of the electric pole type is a critical factor for the successful passing-over the electric pole. The CCD camera installed on the mobile robot captures the image of the electric pole while it is approaching to the electric pole. Applying the dynamic PCA algorithm to the CCD image, the electric pole type has been classified to provide the stable grasping operation for the mobile robot. The new dynamic PCA algorithm replaces the reference image in real time to improve the robustness of the PCA algorithm, adjusts the brightness to get the clear images, and applies the Laplacian edge detection algorithm to increase the recognition rate of electric pole type. Through the real experiments, the effectiveness of this proposed dynamic PCA algorithm method using Laplacian edge detecting method has been demonstrated, which improves the recognition rate about 20% comparing to the conventional PCA algorithm.

• 한국통신학회논문지
• /
• 제26권11A호
• /
• pp.1957-1962
• /
• 2001

영상 압축 또는 영상 부호화에서 후처리, 복원, transcoding을 하는 경우, DCT 계수의 양자화 잡음 모델이 필요하다. 양자화 된 계수만 알고 있는 경우에는 양자화 되기 전의 분포를 구할 수 없다. 본 논문에서는 양자화 되기 전의 DCT 계수의 확률 분포함수를 Laplacian으로 가정하고, 양자화된 계수로부터 분산을 구하고 이를 사용하여 양자화 이전의 분산을 추정하는 방법을 제시하였다. 여러 영상을 사용한 실험을 통하여 제안된 방법의 결과가 기존의 방법에서는 분산이 작게 나오는 단점을 보완하는 것을 확인하였다.

• 한국통신학회논문지
• /
• 제18권11호
• /
• pp.1618-1625
• /
• 1993

비손실 라플라시안 파라미드를 이용한 영상 전송에서 최종 재생 영상의 화질은 각 계층별 부호화율과는 상관없이 거의 일정하게 나타난다. 그러나 저 해상도를 갖는 상위 계층에서 재생 영상의 화질은 각 계층별 부호화율에 따라 큰 차이를 나타낸다. 본 논문에서는 상위 계층에서는 우수한 재생 영상을 얻으며, 최종 재생 영상에서는 왜곡을 최소화할 수 있는 계층별 최적 비트 배정 방식을 제안하였다. 제안된 방식에 의한 재생 영상은 기존의 방식에 비해 저 해상도를 갖는 계층에서의 높은 PSNR과 우수한 화질을 나타내므로 보다 효율적인 점진적 영상 전송이 가능하였다.