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A Reduced Reference Image Quality Measure Using Bessel K Forms Model for Tetrolet Coefficients
Abdelkaher Ait Abdelouahad1„ Mohammed El Hassouni, Hocine Cherifi, Driss Aboutajdine
To cite this version:
Abdelkaher Ait Abdelouahad1„ Mohammed El Hassouni, Hocine Cherifi, Driss Aboutajdine. A Re-
duced Reference Image Quality Measure Using Bessel K Forms Model for Tetrolet Coefficients. Journal
of Convergence Information Technology, Advanced Institute of Convergence Information Technology
Research Center, 2011, 6, pp.216, 224. �hal-00653086�
A Reduced Reference Image Quality Measure Using Bessel K Forms Model for Tetrolet Coefficients
1
Abdelkaher Ait Abdelouahad,
2Mohammed El Hassouni,
3Hocine Cherifi,
4Driss Aboutajdine
*1, 4
LRIT URAC 29-University of Mohammed V-Agdal-Morocco,
[email protected] [email protected]
2,
DESTEC FLSHR- University of Mohammed V-Agdal-Morocco, [email protected]
3,
Le2i-UMR CNRS 5158-University of Burgundy, Dijon-France, [email protected]
Abstract
In this paper, we introduce a Reduced Reference Image Quality Assessment (RRIQA) measure based on the natural image statistic approach. A new adaptive transform called ”Tetrolet” is applied to both reference and distorted images. To model the marginal distribution of tetrolet coefficients Bessel K Forms (BKF) density is proposed. Estimating the parameters of this distribution allows to summarize the reference image with a small amount of side information. Five distortion measures based on the BKF parameters of the original and processed image are used to predict quality scores.
A comparison between these measures is presented showing a good consistency with human judgment.
Keywords: Reduced Reference Image Quality Assessment, Tetrolet coefficients, Bessel K Forms.
1. Introduction
Since the advent of digital images, image processing techniques are increasingly in demand.
However, such techniques like compression, quantization watermarking [1] and denoising [2] affect the image perceived quality. Thus, an objective image quality assessment measure is required to compare and to monitor the performances of image processing algorithms [3]. Depending on the availability of the reference image we can distinguish three types of objective image quality assessment methods. When the reference image is available the measures belong to the Full Reference (FR) class.
The Peak Signal-to-Noise Ratio (PSNR) and the Mean Structural Similarity Index (MSSIM)[4], are both widely used FR methods. No reference (NR) methods, aim to quantify the quality of a distorted image without any cue from its original version. They are generally conceived for specific distortion type and cannot be generalized for other distortions [5]. Reduced Reference (RR) methods are typically used when one can send side information with the processed image related to the reference. Recently, a number of authors have successfully introduced RR methods based on: image distortion modeling [6][7], human visual system (HVS) modeling [8][9], and finally natural image statistics modeling [10][11]. As our work falls in the last approach we recall its underlying assumption. Natural images statistics are the basic stimuli that our visual system is adapted to. After processing, the statistics of the images change and make it unnatural. Understanding the way by which statistics change and measuring these changes allows us to predict the visual degradation.
In [10], Wang et al used the steerable pyramids to represent the distorted and the reference images
in the spatial-frequency domain. First, the subbands coefficients are fitted with the Generalized
Gaussian Density (GGD). Second, the Kullback Leibler Divergence (KLD) is used to quantify the
visual degradation. This approach has introduced a convenient way to assess the quality. It provides
quality scores highly correlated with human judgment for a wide range of distortion types. However,
with only four orientations the steerable pyramids fails to span 360° of orientation space accurately.
Wuf scal amp distr para of th impr prop mod sche tetro expe
2. M
S simu the pyra adap Tetr key opti thre the l
T com distr the u upon cont the l to m Gau dens well mod the B
feng [12], pro e, the Strong plitude among ribution. The ameter of a dis
he geometric rovements we position to us del. The paper eme of the pro olet coefficien eriments and r
Method
Steerable Pyra ultaneously in image are dis amids which ptive transfor rominoes are s point of this mal in the sen e orientations local structura The tetrolet tra mpared with
ribution is hig use of kurtosi n the kurtosis text of RR, a m large magnitu model margina ussian Density sity for two re l fit the observ dels, 2) its par
BKF paramete
oposed the use gest Compone
g all orientati absolute dev storted image
mean of thes ere remarked se a more flex
r is organized oposed RRIQA nts statistics w results. Finally
amids provid n space and fre regarded. Thi
are direction rm derived shape obtained
transform, wh nse that the lo
the combinat al information
ansform is a s the classical ghly non Gaus
s as a measure s, as an index measure based de of the kurto al distribution y (GGD) for
easons : 1) it ved marginal d rameters are es ers takes into a
Figure 1. The
e of eight ori ent Map (SCM
ions, and the viation and t and the scale e deviations i d compared w
xible image r d as follows: S
A. The tetrole while section y, a conclusion
de a conveni equency. How is can be expl nal derivative
from the Ha d by connectin here an optim ocal geometric tion of tetromi in the image.
sparse represe tensor prod ssian with a h e of peakedne of quality. H d on kurtosis c osis in some s n of tetrolet c
modeling stee is a leptokurt distribution co stimated essen account the pe
e deployment
ientations and M) is constru
n the coeffic the relative d parameter of is derived to q with the prev
representation Section 2 relat et transform is 5 concerns th n ends the pap
ient framewor wever, using th
ained by the n operators. T aar wavelet ng four equal mal tetrominoe c structures are
inoes in each c
entation which duct wavelet eavy tails and ess. In [13] and High correlatio
cannot always ubbands. One coefficients. W erable pyrami tic distribution omparing to S ntially based o eakedness of t
scheme of the
d six scales of ucted from th cients of the deviation are f the reference
quantify the p ious approach
and to deriv tes our motiva s presented in he distortion m per.
rk for locali his representat nature of the b o solve this
transform an sized squares s-based cover e taken into a covering prov
h reduces the n transform. T d a sharp peak d [14], NR me on with HVS s reflect the vi e can use a pro Wang et al [1 ids coefficient n, and as it wa
ymmetric Alp on the kurtosi tetrolet coeffic
e proposed RR
f the same tra he coefficients
SCM are fitt computed be image. Finall perceptual dist h. These resu ve an adequate ations and pre section 3. Se measure. Sect
ized represent tion, the geom basis function drawback we nd based on . “Tiling by te ring is wanted ccount. Furthe vides more dire
number of wa Thus, the tetr k. Such a beha easures have b was obtained.
sual degradati obability densi 0], have used ts. Here, we p as shown in [ pha Stable (Sα
s [17], thus a cients.
RIQA measure
ansform. For e s with maxim ted to a Wei etween the s ly, the summa tortion. Impor ults motivate e image stat esents the gen ection 4, descr tion 6 relates
tation of sig metric structure ns of the steer e propose a n “teteromino
etrominoes” is d. The coverin ermore, with o ections adapte
avelet coeffici rolet coeffici avior can invo been implemen
. However, in ion. This is du ity function (P d the General propose the B 15], the BKF αS) [16] and G measure based
e
each mum ibull scale ation rtant our tistic neral ribes our
gnals es of rable new oes”.
s the ng is only ed to
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olves
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can
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T squa , j
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base Figu imag geom
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Once the BKF oduce measure s can help to r ed on the abso tive deviation ameters togeth bability densit vides a measur
Tetrolet tra
The Haar wave ares, this nec
,..., 2
0 N
= , we
ed partition ta ure 2 shows an
ge. The idea o metry by bring
Tetrominoes ar can obtain a t have five free
The Haar tran er tetrominoes ereas 8× 8 blo ar that the first
Let’s take the e he one whose
mal covering tions and refl
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ansform
elet transform essitates a dy
have I
i,j= {
akes into acco n example wh of tetrolet tran
ging the “tiling
Figure 2 re derived fro tetromino by c
tetrominoes a
nsform is a sp s we should h ocks gives 117 t choice is the
Figure example in Fi e tetrominoes g is illustrated lections are co
are estimated, either the sha mber of featur the difference hose ones. Sec uses the pseu (PDFs). Fig.1 reference imag
m consist in ave yadic partition
( ) (
{ 2 i , 2 j , 2 i + ount structura here the Haar nsform is to al g by tetromino
2. The Haar tr om the well kn connecting fou as shown in Fi
Figure 3. t pecial case, sin have at least a
8
4
10
7 > poss reasonable on
4. The 22 fun gure 2, severa do not inters d in Figure 5 onsidered. To
, we proceed ape parameter res extracted fr e between par cond, we pres udo metric 1 illustrates th ge and its disto
eraging of sum n of the imag
) ( , 2 , 2
2 ,
+ 1 j i j al image. How
transform is n low more gen oes” problem
ransform appli now game “tet ur equal sized
gure 3.
the five free te nce it conside a 4× 4 blocks sibilities. From ne.
ndamental form al tetrominoes- sect an import 5. Therefore, illustrate this
to calculate t or the scale p from the refere rameters or are sent a measur to quantify th he RRIQA pr orted version.
m and differen ge index set
) ( , 2 1 , 2
1 +
+ i
j
wever image not able to cap neral partitions
into play.
ied to an imag tris”. They we d square. Disr
etrominoes ers only the fi s (Figure 4) w m computatio
ms tiling a 4x4 -based coverin tant geometri
tetrominoes s let’s take fro
the quality me parameter of th ence image. Th e based on the re which inco he difference b roposed schem
nces of pixels
⎩ ⎨
= ⎧ I
0,0,..., I E
)}
1 2 j + . Alth
local geometr pture the loca s which captur
ge block.
ere introduced regarding rotat
first tetromino which will giv nal complexit
4 board.
ng are possible c structure lik ensure more om Figure 4 (
easures. First, he BKF den hese measures e absolute and orporates the between two B
me. This sch
arranged in 2
⎭ ⎬
⎫
,2 2
N
I
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ry is disregar al geometry of re the image l
d by Golomb [ tion and isome
o (square). To ve 117 possibi
ty standpoint,
e, the optimal ke an edge. S e directions w (Line 4) the t
, we nsity.
s are d the two BKF heme
2 2 × e for
uare rded.
f the local
[18].
etric
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when
third
cove Figu
T opti cove gene coef min min
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T in I disto obse of t coef imag sam imag
Figu disto
ering (from le ure 6.
The adaptivity mization proc ering are con erates four low fficients is use
imal l
1norm imal is the l
1Tetrolet coe
The strong ada IQA purpose.
ortion types.
erve how these this study. Fi fficients of a s ge is also repo me representati
ge, respective
(a) bl ure 7. Distord ortion types. D
eft to right), e
Figure 5. A
Figure 6. D y of the tetr cess used in th nsidered. For
w-pass coeffi ed to determin m. In other wo
norm. Thus w
efficients st
aptive relevanc Moreover, w For this goal e distortions c igure .7 (a) r subband of this orted for comp ions for the w
ly.
lur
ded Images and Dashed curves
eight other cov
An optimal tili
Different direc rolet transfor he filter bank each covering icients and 12
ne the optima ords, the sma we obtain the o
atistics
ce of tetrolet t we can demon
l, we apply a change the stat represents a s image (solid parative purpo white noise c
(b d correspondin s : the original
vering are pos
ing for the pro
tions covered rm to the lo k algorithm [1 g the Haar tr 2 tetrolet coef al covering. T aller is the ma optimal coverin
transform and nstrate the se a tetrolet trans
tistics of tetrol Gaussian blur d curve). The h ose (dashed cu ontaminated i
b) white noise ng Histograms image. Solid
ssible with di
oposed image b
by the same t ocal geometri 9]. Given a 4 ransform is a fficients, then This later is ch agnitude of th ng and a spars
its sparseness ensitivity of te sform to diffe let coefficients rred image a histogram of th urve). Figure . image and th
e
s of Tetrolet c curves : distor
fferent directi
block (left).
etrominoes.
c structures 4
4 × block, th applied to its the l
1norm hosen as the o
he 12 tetrolet se image repre
s provide good etrolets coeffi erent distorted s. Figure.7 illu and the histo he same subba .7 (b) and Figu he transmissio
(c) transm oefficients un rted image.
ions are show
comes from he 117 admiss
tetrominoes, of the 12 tetr one who have t coefficients, esentation.
d reasons to u ficients to var d images and ustrates the res
ogram of tetr and of the orig ure .7 (c) give on errors disto
mission errors nder various
wn in
the sible this rolet e the the
use it rious d we
sults
rolet
ginal
e the
orted
The PDF of the BKF model is given by [15] :
; , 1
√ Γ 2 2
2 | | , (1)
Where Γ . is the Gamma function, and are the shape and scale parameters, respectively. K is the modified Bessel function given by:
Γ 1
2 2
√
cos ,
∝
(2)
The BKF parameters can be estimated using the Maximum Likelihood method [17] : and
5. Distortion measures
The first two measures are based on the absolute value of the difference between the shape or scale parameter of a subband and its corresponding from the distorted image. For the rest of this section we consider ( ) and ( ) as the shape (scale) parameter of a subband from the reference image and its corresponding from the distorted image, respectively. The measures are:
| |, (3)
| |
(4) The second type of measure is based on absolute deviation and relative deviation [12]. For the shape parameter, we have :
| | and
| |The summation of the geometric mean of and over all Subbands is computed to predict the visual degradation as follows :
, (5)
The same measure can be derived for the scale parameter β as follows :
, (6)
To quantify the difference between two PDFs the well known Kullback Leibler Divergence (KLD) can be used. Nevertheless, according to our knowledge there is no closed form for the KLD for BKF PDFs. Here, we propose the use of metric [15]. Let ; , and ; , be two BKF PDFs, the metric can be expressed as :
, , , ; , ; , (7)
More explicitly, this distance can be simplified as :
, , , 1
2√2 Γ 0.5 2 2 2
, (8)
Where
Γ .Γ