Most of the standard image and video codecs are block-based and depending upon the compression ratio the compressed images/videos suffer from different distortions. At low ratios, blurriness is observed and as compression increases blocking artifacts occur. Generally, in order to reduce blockiness, images are low-pass filtered which leads to more blurriness. Also, in bokeh mode images they are commonly seen: blurriness as a result of intentional blurred background while blocking artifact and global blurriness arising due to compression. Therefore, such visual media suffer from both blockiness and blurriness distortions. Along with this, noise is also commonly encountered distortion. Most of the existing works on quality assessment quantify these distortions individually. This paper proposes a methodology to blindly measure overall quality of an image suffering from these distortions, individually as well as jointly. This is achieved by considering the sum of absolute values of low and high-frequency Discrete Frequency Transform (DFT) coefficients defined as sum magnitudes. The number of blocks lying in specific ranges of sum magnitudes including zero-valued AC coefficients and mean of 100 maximum and 100 minimum values of these sum magnitudes are used as feature vectors. These features are then fed to the Machine Learning (ML) based Gaussian Process Regression (GPR) model, which quantifies the image quality. The simulation results show that the proposed method can estimate the quality of images distorted with the blockiness, blurriness, noise and their combinations. It is relatively fast compared to many state-of-art methods, and therefore is suitable for real-time quality monitoring applications.
翻译:大多数标准图像和视频编码器都是基于块状的,视压缩比例而定,压缩图像/视频的扭曲程度不同。在低比率下,观察到模糊性,而且随着压缩增加阻碍文物的现象发生。一般而言,为了减少阻塞性,图像是经过低通路过滤的,从而导致更模糊性。在bokeh模式图像中,人们通常看到:由于故意模糊背景而导致模糊性,同时屏蔽工艺品和压缩产生的全球模糊性。因此,这些视觉媒体既受到阻塞性,又受到模糊性扭曲性扭曲性的影响。此外,噪音也是常见的扭曲性。大多数关于质量评估的现有工作都对这些扭曲进行单独量化。本文建议了一种方法,以便盲目地衡量因这些扭曲而蒙受的图像的总体质量质量,单独或共同地进行。通过考虑低频和高频变频变频系数的绝对值之和总数值来界定。因此,这类视觉介质介质的组合在特定范围内,包括低值的AC系数和最小值为100个,而质量应用的数值是相对质量的数值,而相对质量的数值则用G值来测量质量的数值来显示。这些质量的模型的模型显示,这些质量的模型的模型的数值是快速度,这些质量的模型的模型的模型的模型的模型和比例值是用来用来显示。</s>