• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.6
• /
• pp.773-778
• /
• 1993

A new approach is proposed for the DCT which is widely utilized in the image processing, The approach replaces mutiplications with shift and additions, In the image restored by the proposed DCT and IDCT, no visible degration is observed and PSNR(Peak to Peak Signal to Noise Ratio) is greater than 35 dB for all cases, proving the usefulness of the proposal.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.9
• /
• pp.2265-2271
• /
• 2014

In modern society digital equipments that are related with various hardware and software are popularized, and digital images are widely applied in the field of production and scientific research. In general, however, images are degraded by the noise in the process of transmission and storage. In this paper, to reduce the influence of mixed noises, the algorithm in which noises in the space area are classified into impulse noise and Gaussian noise and this is processed by applying weighted value, while that is processed by modified nonlinear filter is proposed. And the excellence of the proposed algorithm is judged by PSNR(peak signal to noise ratio).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.936-939
• /
• 2015

Recently, the image processing is utilized in various fields and many studies on the image restoration have been carried out in order to remove the noise occurring in the process of data transmission, processing and storage. There are many types of noises added to the image according to the cause and shape, and AWGN(additive white Gaussian noise) is one of typical noises. This paper proposed an algorithm which applies the weighting of filter differently according to the standard deviation in order to alleviate AWGN added to the image, and compared this algorithm with the current methods using PSNR(peak signal to noise ratio) as a criterion of judgment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.274-276
• /
• 2015

The image processing is recognized as an important field as Internet develops. The image is deteriorated in the process of obtaining, storage and transmission with various causes. Many studies have been carried out to restore the image by mainly removing the impact of salt and pepper noise added to the image. Thus, this paper proposed a modified median filter using pixel distribution in order to remove the impact of salt and pepper noise added to the image and compared it with the current methods using PSNR(peak signal to n oise ratio) as a criterion of judgment for objective judgment.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.7
• /
• pp.1734-1739
• /
• 2014

Currently, with the rapid development of the digital age, multimedia-related image devices become popular. However, images are susceptible to corruption in processing image data due to the impulse noise and active researches have been conducted to restore these images. This paper, in order to restore the damaged images in impulse noise environments, suggested an image restoration algorithm which applies weights depending on spatial distance between directionality and pixel by focusing on damaged pixels. Additionally, this algorithm was compared with existing methods by using the PSNR (peak signal to noise ratio) as the objective standard to judge whether there were improved effects.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.694-696
• /
• 2017

Image processing is being hailed as an important field with various applications as the digital information era advances. In particular, studies on methods to remove noise from images are being actively undertaken. This paper suggests an image restoration filter that processes through a weighted filter in accordance with the direction of partial masks to preserve edge while replacing the noise in the images with neighboring pixels. The PSNR(peak signal to noise ratio) was used as a tool to objectively judge the improvement effects compared to existing methods.

• Journal of the Korean Society of Radiology
• /
• v.15 no.1
• /
• pp.9-14
• /
• 2021

Recently, magnetic resonance imaging (MRI), which can acquire images with good contrast without exposure to radiation, has been widely used for diagnosis. However, noise that reduces the accuracy of diagnosis is essentially generated when acquiring the MR images, and by adjusting the parameters, the noise problem can be solved to obtain an image with excellent characteristics. Among the parameters, the number of excitation (NEX) can acquire images with excellent characteristics without additional degradation of image characteristics. In contrast, appropriate NEX setting is required since the scan time increases and motion artifacts may occur. Therefore, in this study, after fixing all MRI parameters through the MRiLab simulation program, we tried to evaluate the tendency of image characteristics according to changing NEX through quantitative evaluation of brain T2 weighted images acquired by adjusting only NEX. To evaluate the noise level and similarity of the acquired image, signal to noise ratio (SNR), contrast to noise ratio (CNR), root mean square error (RMSE) and peak signal to noise ratio (PSNR) were calculated. As a result, both noise level and similarity evaluation factors showed improved values as NEX increased, while the increasing width gradually decreased. In conclusion, we demonstrated that an appropriate NEX setting is important because an excessively large NEX does not affect image characteristics improvement and cause motion artifacts due to a long scan.

• Journal of the Institute of Convergence Signal Processing
• /
• v.24 no.1
• /
• pp.1-14
• /
• 2023

Underwater images carry information that is useful in the fields of aquaculture, underwater military security, navigation, transportation, and so on. In this research, we transmitted an underwater image through various underwater mediums in the presence of underwater turbulence and beam attenuation effects using a high-speed visible optical carrier signal. The optical beam undergoes scintillation because of the turbulence and attenuation effects; therefore, distorted images were observed at the receiver end. To understand the behavior of the communication media, we obtained the bit error rate (BER) performance of the system with respect to the average signal-to-noise ratio (SNR). Also, the structural similarity index (SSI) and peak SNR (PSNR) metrics of the received image were evaluated. Based on the received images, we employed suitable nonlinear filters to recover the distorted images and enhance them further. The BER, SSI, and PSNR metrics of the specific nonlinear filters were also evaluated and compared with the unfiltered metrics. These metrics were evaluated using the on-off keying and binary phase-shift keying modulation techniques for the 50-m and 100-m links for beam attenuation resulting from pure seawater, clear ocean water, and coastal ocean water mediums.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.877-879
• /
• 2013

Imaging device such as digital TV is being popular in a modern society based on communication technology. However, because of internal and external cause of system in the process of transmission, storage and acquisition, image is degraded by noise. Therefore, the importance of denoising technology is being increased, and a research for that is being actively made. In this paper, a weighted filter algorithm that considers different pixels of masks and estimated noise variance was proposed. in order to remove AWGN. And, PSNR(peak signal to noise ratio) was used to represent the excellence of proposed algorithm.

• Journal of Broadcast Engineering
• /
• v.7 no.4
• /
• pp.291-299
• /
• 2002

This paper proposes an efficient motion compensation algorithm for video sequences with brightness variations. In the proposed algorithm, the brightness variation parameters are estimated and local motions are compensated. To detect the frame with large brightness variations. we employ the frame classification based on the cross entropy between histograms of two successive frames, which can reduce the computational redundancy. Simulation results show that the proposed method yields a higher peak signal to noise ratio (PSNR) than the conventional methods, with a low computational load, when the video scene contains large brightness changes.