ISSN: 2319-5967
ISO 9001:2008 Certified
International Journal of Engineering Science and Innovative Technology (IJESIT)
Volume 2, Issue 5, September 2013
Abstract— we develop an efficient BLIINDS-II algorithm using NSS approach in DCT domain for image and video
quality assessment with no reference image. The approach relies on a simple Bayesian inference model to predict image
and video quality score, after a set of features is extracted from an image. These features are extracted from a generalized
NSS based model of local DCT coefficients. Generalized Gaussian density model parameters are used to form these
features. BLIINDS-II (Blind Image Integrity notator using DCT Statistics-II) adopts a simple probabilistic model for
score prediction. Given the extracted features from a test image/video, the quality score that maximizes the probability of
the empirically determined inference model is chosen as the predicted quality score of that image/video. When tested on the
LIVE IQA database, BLIINDS-II correlates highly with the human judgments of quality.
Index Terms— Bayesian inference model, Image quality assessment (IQA), Natural scene statistics, Video quality
assessment (VQA).
I. INTRODUCTION
Digital video data, stored in video databases and distributed through communication networks, is subject to various
kinds of distortions during acquisition, compression, processing, transmission, and reproduction. For example,
lossy video compression techniques, which are almost always used to reduce the bandwidth needed to store or
transmit video data, may degrade the quality during the quantization process. It is therefore imperative for a video
service system to be able to realize and quantify the video quality degradations [8] that occur in the system, so that
it can maintain, control and possibly enhance the quality of the video data. An effective image and video quality
metric is crucial for this purpose.
The most reliable way of assessing the quality of an image or video is subjective evaluation, because human beings
are the ultimate receivers in most applications. The mean opinion score (MOS), which is a subjective quality
measurement obtained from a number of human observers, has been regarded for many years as the most reliable
form of quality measurement. However, the MOS method is too inconvenient, slow and expensive for most
applications which lead to the objective image and video quality assessment.
The goal of objective image and video quality assessment research is to design quality metrics that can predict
perceived image and video quality automatically.
Objective image and video quality metrics can be classified according to the availability of the original image and
video signal, which is considered to be distortion-free or perfect quality, and may be used as a reference to compare
a distorted image or video signal against. Most of the proposed objective quality metrics in the literature assume
that the undistorted reference signal is fully available. Although “image and video quality” is frequently used for
historical reasons, the more precise term for this type of metric would be image and video similarity or fidelity
measurement, or full-reference (FR) image and video quality assessment.
It is worth noting that in many practical video service applications, the reference images or video sequences are
often not accessible. So, certain features are extracted from the original signal and transmitted to the quality
assessment system as side information to help evaluate the quality of the distorted image or video. This is referred
to as reduced-reference (RR) image and video quality assessment.
There exists an image and video quality assessment method, in which the original image or video signal is not fully
available i.e., It is highly desirable to develop measurement approaches that can evaluate image and video quality
blindly. Blind or no-reference (NR) image and video quality assessment turns out to be a very difficult task,
although human observers usually can effectively and reliably assess the quality of distorted image or video
without using any reference
Image and Video Quality Assessment with
BLIINDS-II Algorithm using NSS Approach in
DCT domain
M. Santhoshi, S. Aruna Kumari, S. Srikanth Reddy, A. Vijay Kumar