• Title/Summary/Keyword: PSNR

Search Result 1,511, Processing Time 0.031 seconds

Spatial and Temporal Resolution Selection for Bit Stream Extraction in H.264 Scalable Video Coding (H.264 SVC에서 비트 스트림 추출을 위한 공간과 시간 해상도 선택 기법)

  • Kim, Nam-Yun;Hwang, Ho-Young
    • Journal of Korea Multimedia Society
    • /
    • v.13 no.1
    • /
    • pp.102-110
    • /
    • 2010
  • H.264 SVC(Scalable Video Coding) provides the advantages of low disk storage requirement and high scalability. However, a streaming server or a user terminal has to extract a bit stream from SVC file. This paper proposes a bit stream extraction method which can get the maximum PSNR value while date bit rate does not exceed the available network bandwidth. To do this, this paper obtains the information about extraction points which can get the maximum PSNR value offline and decides the spatial/temporal resolution of a bit stream at run-time. This resolution information along with available network bandwidth is used as the parameters to a bit stream extractor. Through experiment with JSVM reference software, we proved that proposed bit stream extraction method can get a higher PSNR value.

Implementation of Filter for the Removal of Partial Volume Effect (부분용적효과 제거를 위한 Filter 구현)

  • Park, Minju;Lee, Sangbock
    • Journal of the Korean Society of Radiology
    • /
    • v.9 no.3
    • /
    • pp.139-145
    • /
    • 2015
  • When examining a patient using SPECT, gamma rays emitted from the body decrease or scatter. And when they reach the detector they spread in accordance with physical characteristics and geometric shapes of the scanner, quantitative analysis was difficult. For exact quantitative analysis of gamma rays emitted from the body, so that they must be considered to correction about PVE(partial volume effect). In this paper, sinogram filter was implemented to solve comprehensive PVE of SPECT. According to the results in which implemented filter was applied, partial volume effect caused by SPECT was removed. To compare proposed method and conventional method, PSNR(Peak Signal to Noise Ratio) was executed. As a result, proposed method was indicated as 7dB, conventional method was indicated as 14db respectively. dB(decibel) level of the proposed methods is lower, since the MSE(mean square error) becomes greater because scattered ray was removed, PSNR value is low. Therefore, by applying the proposed method for removing the PVE of SPECT imaging method, the image quality is improved.

Quality Improvement Scheme of Interpolated Image using the Characteristics of the Adjacent Pixels (인접 픽셀들의 특성을 이용한 보간 영상의 화질 개선 기법)

  • Jung, Soo-Mok
    • Journal of the Korea Society of Computer and Information
    • /
    • v.16 no.11
    • /
    • pp.95-102
    • /
    • 2011
  • Interpolation schemes are used widely in image magnification. Magnified image generated by interpolation scheme is composed of the known pixels in input image and the interpolated pixels estimated from the known pixels in input image. So, as the interpolated pixels are estimated to have locality which exists in real images, the magnified image is much closer to the real image. In this paper, an efficient interpolation scheme was proposed to provide locality for the interpolated pixels by using the characteristics of adjacent pixels in input image. The quality of magnified image using the proposed scheme was improved. In experiment, PSNR(Peak Signal to Noise Ratio) was used to evaluate the performance of the proposed scheme. The PSNR's of the magnified images generated by the proposed scheme were greater than those of the magnified images generated by the previous interpolation methods.

ASTC Block-Size Determination Method based on PSNR Values (PSNR 값 기반의 자동화된 ASTC 블록 크기 결정 방법)

  • Nah, Jae-Ho
    • Journal of the Korea Computer Graphics Society
    • /
    • v.28 no.2
    • /
    • pp.21-28
    • /
    • 2022
  • ASTC is one of the standard texture formats supported in OpenGL ES 3.2 and Vulkan 1.0 (and later versions), and it has been increasingly used on mobile platforms (Android and iOS). ASTC's most important feature is the block size configuration, thereby providing a trade-off between compression quality and rates. With the higher number of textures, however, it is difficult to manually determine the optimal block sizes of each texture. To solve the problem, we present a new approach based on PSNR values to automatically determine the ASTC block size. A brute-force approach, which compresses a texture on all block sizes and compares the PSNR values of the compressed textures, can increase the compression time by up to 14 times. In contrast, our three-step approach minimizes the compression-time overhead. According to our experiments on a texture set including 64 various textures, our method determined the block sizes from 4×4 to 12×12 and reduced the size of compressed files by 68%.

Median Modified Wiener Filter for Noise Reduction in Computed Tomographic Image using Simulated Male Adult Human Phantom (시뮬레이션된 성인 남성 인체모형 팬텀을 이용한 전산화단층촬영 에서의 노이즈 제거를 위한 Median Modified Wiener 필터)

  • Ju, Sunguk;An, Byungheon;Kang, Seong-Hyeon;Lee, Youngjin
    • Journal of the Korean Society of Radiology
    • /
    • v.15 no.1
    • /
    • pp.21-28
    • /
    • 2021
  • Computed tomography (CT) has the problem of having more radiation exposure compared to other radiographic apparatus. There is a low-dose imaging technique for reducing exposure, but it has a disadvantage of increasing noise in the image. To compensate for this, various noise reduction algorithms have been developed that improve image quality while reducing the exposure dose of patients, of which the median modified Wiener filter (MMWF) algorithm that can be effectively applied to CT devices with excellent time resolution has been presented. The purpose of this study is to optimize the mask size of MMWF algorithm and to see the excellence of noise reduction of MMWF algorithm for existing algorithms. After applying the MMWF algorithm with each mask sizes set from the MASH phantom abdominal images acquired using the MATLAB program, which includes Gaussian noise added, and compared the values of root mean square error (RMSE), peak signal-to-noise ratio (PSNR), coefficient correlation (CC), and universal image quality index (UQI). The results showed that RMSE value was the lowest and PSNR, CC and UQI values were the highest in the 5 x 5 mask size. In addition, comparing Gaussian filter, median filter, Wiener filter, and MMWF with RMSE, PSNR, CC, and UQI by applying the optimized mask size. As a result, the most improved RMSE, PSNR, CC, and UQI values were showed in MMWF algorithms.

Fractal Image Coding in Wavelet Transform Domain Using Absolute Values of Significant Coefficient Trees (유효계수 트리의 절대치를 이용한 웨이브릿 변화 영역에서의 프랙탈 영상 압축)

  • Bae, Sung-Ho;Kim, Hyun-Soon
    • The Transactions of the Korea Information Processing Society
    • /
    • v.5 no.4
    • /
    • pp.1048-1056
    • /
    • 1998
  • In this paper, a fractal image coding based on discrete wavelet transform is proposed to improve PSNR at low bit rates and reduce computational complexity of encoding process. The proposed method takes the absolute value of discrete wavelet transform coefficients, and then constructs significant coefficients trees, which indicate the positions and signs of the significant coefficients. This method improves PSNR and reduces computational complexity of mapping contracted domain pool onto range block, by matching only the significant coefficients of range block to coefficients of contracted domain block. Also, this paper proposes a classification scheme which minimizes the number of contracted domain blocks compared with range block. This scheme significantly reduces the number of range and contracted domain block comparison.

  • PDF

An Image Denoising Algorithm Using Multiple Images for Mobile Smartphone Cameras (스마트폰 카메라에서 다중 영상을 이용한 영상 잡음 제거 알고리즘)

  • Kim, Sung-Un
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.9 no.10
    • /
    • pp.1189-1195
    • /
    • 2014
  • In this study we propose an image denoising algorithm which manipulates the information obtained from multiple images in the same environment for mobile smart phones. We also envisage a multiple images registration method for mobile smart phone cameras equipped with limited computing ability and present an effective image denoising algorithm combining and manipulating the information obtained from multiple images. We proved that the proposed algorithm has much better PSNR value than the method applying single image. We verified that the propose approach has good denoising quality and can be utilized in the feasible level speed on Android smart phones.

VLSI Architecture of Digital Image Scaler Combining Linear Interpolation and Cubic Convolution Interpolation (선형 보간법과 3차회선 보간법을 결합한 디지털 영상 스케일러의 VLSI 구조)

  • Moon, Hae Min;Pan, Sung Bum
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.51 no.3
    • /
    • pp.112-118
    • /
    • 2014
  • As higher quality of image is required for digital image scaling, longer processing time is required. Therefore the technology that can make higher quality image quickly is needed. We propose the double linear-cubic convolution interpolation which creates the high quality image with low complexity and hardware resources. The proposed interpolation methods which are made up of four one-dimensional linear interpolations and one one-dimensional cubic convolution perform linear-cubic convolution interpolation in horizontal and vertical direction. When compared in aspects of peak signal-to-noise ratio(PSNR), performance time and amount of hardware resources, the proposed interpolation provided better PSNR, low complexity and less hardware resources than bicubic convolution interpolation.

Soft Thresholding Method Using Gabor Cosine and Sine Transform for Image Denoising (영상 잡음제거를 위한 게이버 코사인과 사인 변환의 소프트 문턱 방법)

  • Lee, Juck-Sik
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.11 no.1
    • /
    • pp.1-8
    • /
    • 2010
  • Noise removal methods for noisy images have been studied a lot in the domain of spatial and transform filtering. Low pass filtering was initially applied in the spatial domain. Recently, discrete wavelet transform has widely used for image denoising as well as image compression due to an excellent energy compaction and a property of multiresolution. In this paper, Gabor cosine and sine transform which is considered as human visual filter is applied to image denoising areas using soft thresholding technique. GCST is compared with excellent wavelet transform which uses existing soft thresholding methods from PSNR point of view. Resultant images removed noises are also visually compared. Experimental results with adding four different standard deviation levels of Gaussian distributed noises to real images show that the proposed transform has better PSNR performance of a maximum of 1.18 dB and visible perception than wavelet transform.

A quality improvement scheme of magnified image using effectively the various curved surface characteristics of Image (영상의 다양한 곡면 특성을 효과적으로 활용한 확대 영상의 화질 개선 기법)

  • Jung, Soo-Mok
    • Journal of the Korea Society of Computer and Information
    • /
    • v.20 no.1
    • /
    • pp.63-73
    • /
    • 2015
  • In this paper, a quality improvement scheme is proposed for magnified image using the various curved surface characteristics of image. After testing horizontal and vertical directional surface characteristics of source image, interpolation value is calculated to have the surface characteristics such as simple convex surface, simple concave surface, and compound surface. The calculated interpolation value become the value of the interpolated pixel of magnified image. The calculated interpolation value is closer to the pixel value of real image. So, the quality of the magnified image is improved. The PSNR value of the magnified image using the proposed scheme is larger than the PSNR values of the magnified image using the existing techniques.