and videos (Opozda and Sochan, 2014). It was also
pointed out that image quality is affected by both ob-
server’s attributes and technical properties of presen-
tation (Opozda and Sochan, 2014).
Depending on how the evaluation is performed,
IQA can be achieved in one of two ways: subjective
and objective quality methods. Each of these methods
has its own unique way of evaluation. The following
sub-sections will describe a little bit more about these
evaluation methods.
3.1 Subjective Methods
Subjective quality assessment is a controlled exper-
iment with human participants used to measure per-
ceptual quality. In subjective assessment, human
judges are the golden standard without the advice of
others (Patil and Patil, 2017). Not only that, subjec-
tive methods can also (Ma et al., 2015):
• Provide data which is useful in the study of hu-
man behavior in the evaluation of image quality
perceptions
• Provide a set of tests to assess the relative per-
formance of various image processing algorithms
and methods and compare them
• Be used to assess the relative performance of ob-
jective Image Quality Assessment (IQA) models
that exist today in the prediction of integrated im-
age perceptual quality. This will also provide in-
sight into possible ways of improving it.
Based on the use of stimuli, subjective methods
are classified into single stimulus and double stimu-
lus (Patil and Patil, 2017). There are many different
methodologies and rules for the design of subjective
quality evaluation tests. Usually, in this type of as-
sessment, a number of observer are subjected to im-
ages with various degree of different quality, and are
asked to provide their quality evaluation of these im-
ages. Scores that are assessed by numerous subjects
arrive at the midpoint for each image to get an average
guess score.
Subjective method possess several drawbacks
(Hands, 1998):
• It takes time and money for the test;
• Recruit and pay for subjects;
• The equipment used must be tested and regulated;
• Laboratory;
• Experiments must run tests.
Subjective tests are usually complicated, imprac-
tical, and not feasible for certain applications (Win-
kler, 2005). People turn to objective tests for faster
and more practical results. Subsequently, objective
assessments are tested and verified based on selected
subjective judgments as the ground truth data.
3.2 Objective Methods
In numerous audio-visual services, objective mea-
surements are used to assess the influence of the cod-
ing system and transmission path on the quality of
multimedia data presentations. The goal is to for-
mulate mathematical models that automatically and
accurately predict the quality of the image. Some-
times the use of subjective judgments is necessary for
objective measurement that is appropriate as a refer-
ence evaluation. This allows precise measurements
for certain types of distortion: blur image, blurred
motion, edge, false contouring, granular noise, jerk-
iness, blockage, dirty window. Objective IQA is ap-
plied in various applications such as (Mohammadi
and Shirani, 2014):
• image quality monitoring in quality control sys-
tem
• image processing algorithms and systems com-
parison
• image processing and transmission systems opti-
mization
The Video Quality Expert Group (VQEG) has de-
fined three distinct methods for image/video quality
assessment based on the availability of reference im-
age: full reference (FR), reduced reference (RR), and
no reference (NR) methods (VQEG, 2000), (VQEG,
2002), (VQEG, 2004). These methods will be ex-
plained in the following Secio,
3.2.1 Full-Reference (FR)
Full-Reference (FR) method evaluates the perfor-
mance of the systems by comparing the undistorted
signal at the system input with the degraded signal at
the system output (Opozda and Sochan, 2014). In this
situation, the human visual system requires an allu-
sion sample to define an image’s excellent level (Patil
and Patil, 2017).
3.2.2 No-Reference (NR)
No-Reference (NR) image quality model makes use
of characteristics of HVS. Human eye does not need
a source test or is based only on the processed image
where the reference image is not available to deter-
mine the level of excellence of the image (Opozda and
Sochan, 2014); (Patil and Patil, 2017). The animation
quality rating scheme has no access to reference im-
ages in many tactical apps. It is therefore anticipated
High Dynamic Range (HDR) Image Quality Assessment: A Survey
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