IQA 暑期班 2017 -...

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Fei Gaogaofei@hdu.edu.cn

http://camalab.hdu.edu.cn

Hangzhou Dianzi University

Image Quality Assessment via Deep Learning 2

Contents

• Background

• Image Quality Assessment (IQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions

Image Quality Assessment via Deep Learning 3

Contents

• Background

• Image Quality Assessment (IQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions

Image Quality Assessment via Deep Learning 4

Background

• Dramatically increasing amount of imagesn Devices: computers, mobile phones, cameras, monitors, …

n Applications: medias, websites, IM clients, …

Image Quality Assessment via Deep Learning 5

Background

• Extensively existed distortionsn Processing: acquisition, compression, transmission,

reconstruction, …

n Distortions: blurring, JPEG compression, Gaussian noise, …

Image Quality Assessment via Deep Learning 6

What is Quality?

• Various aspectsn Athletics: perceived beauty or image appeal

n Fidelity: deviation from the undistorted version

n Intelligibility: discriminability of image content

[Keelan,HandbookofImageQuality,2002][JanssenandBlommaert,JIST,1997]

[Janssen,Proc.IEEE,2001][Halonen,etal.,Proc.SPIE,2011]

Athletics FidelityUndistortedDistorted

Intelligibility

Image Quality Assessment via Deep Learning 7

Background

• Demands for IQA metrics

Evaluation, control, and improve the perceptual quality of multimedia content, quality of service (QoS), image processing systems, …

[Z. Wang, IEEE SPM’11]

Diagram of IQA-based feedback optimization

method.

ImageProcessingSystem

UpdatingAlgorithm

IQAEvaluation

Input Output

Image Quality Assessment via Deep Learning 8

Background

• Common Subjective IQA Method

1005 Excellent

4 Good

3 Fair

2 Poor

1 Bad

80

60

20

0

40

Quality Scale/Score

Categorical Continuous

Test image k Test image k+1

T1 = 10s Reference image

T2 = 3s Mid-gray image

T3 = 10s Test image

T4 = 10s Mid-gray image

[ITUR BT.500-13., 2012]

Image Quality Assessment via Deep Learning 9

Contents

• Background

• Image Quality Assessment (IQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions

Image Quality Assessment via Deep Learning 10

Image Quality Assessment (IQA)

• Traditional Objective Methodsn Mean Squared Error (MSE)

n Peak Signal-to-Noise Ratio

n Advantages

• Mathematically conventional

• Effective for white noise

n Disadvantage

• Lack of consideration of human visual property

∑∑= =

−=m

i

n

jjiRjiI

mnMSE

1 1

2),(),(1

⎟⎟⎠

⎞⎜⎜⎝

⎛⋅=

MSEIPSNR2max

10log10

[Wang&Bovik,IEEESPM09]

Brightened(MSE=309) JPEG(MSE=309)

Gaussiannoise(MSE=309) Gaussianblur(MSE=309)

Image Quality Assessment via Deep Learning 11

Image Quality Assessment (IQA)

• How to Construct Objective IQA Metrics?

KnowledgeaboutTheHVS

PerceptualModeling

VisualPhysology andPhychophysics

Knowledgemapexpressing theelementsrequiredtoconstructsuccessful IQAmodels.

[Wang&Bovik,SPM’11]

KnowledgeaboutImageSource

Deterministic Natural Scenestatistics (NSS)

KnowledgeaboutImageDistortions

ArtifactDetection

DistortionModelling

Model-basedImageQualityAssessment

DualProblems

Image Quality Assessment via Deep Learning 12

Image Quality Assessment (IQA)

• Classification of Objective IQA

Reduced-reference(RR)IQAmethods

No-reference(NR)IQAmethods

Full-reference(FR)IQAmethods

RR-IQAmethods

NR-IQAmethods

FR-IQAmethods

Referenceimage

Distortedimage

SubjectiveQualityScores

SupplementaryInformation

Distortedimage

SubjectiveQualityScores

DistortedimageReferenceimage

SubjectiveQualityScores

Image Quality Assessment via Deep Learning 13

Image Quality Assessment (IQA)

• FR-IQA: Structural Similarity Index (SSIM)

Referenceimage!

Distortedimage"

LuminanceMeasure:Meanintensity

#$ =1'( )*

+

*,-

ContrastMeasure:Standarddeviationofintensity

.$ =1

'−1( )* −#$ 0+

*,-

-0

StructureMeasure:Normalizedimage

)−#$ /.$

2 !, " = 2#5#6+ 8-#50 +#60 + 8-

9 !, " = 2.5.6 +80.50 +.60 +80

: !, " = 2.56 +8;.5.6 +8;

<<)= !," =2 !," > ? 9 !," @ ? : !," A

[Z.Wang,etal. TIP’04]

n Advantages: efficient and effective

n Extensions: CBM [X. Gao et al., LNAI’05], IW-SSIM[W. Zhou and Q. Li, TIP’11], RR-SSIM [A. Rehman

and Z. Wang, TIP’12], etc.

Image Quality Assessment via Deep Learning 14

Image Quality Assessment (IQA)

• FR-IQA: Deep Similarity (DeepSim) [F.Gao,etal. NEUCOM’17]

Image Quality Assessment via Deep Learning 15

Image Quality Assessment (IQA)

• RR-IQAn Application: wireless communication scenario

n Framework of RR-IQA System

Distortion Channel

Feature Extraction

Ancillary Channel

Feature Extraction

RR Quality Analysis

Sender Side Receiver Side

original image

quality meature

RR features

distorted image

Image Quality Assessment via Deep Learning 16

Image Quality Assessment (IQA)

• NR-IQAn Convolutional Neural Networks for BIQA (Kang et al. CVPR’14)

50 feature mapsInput patch

32

32 77

minpooling

maxpooling

convolutional 26

26

50

50800

ReLUs ReLUs

linear regressio

noutput(score)

800

a) The input is locally normalized 32�32 image patches;

b) The convolutional layer produces 50 feature maps each of size 26�26, followed by a pooling operation that reduces each feature map to one max and one min;

c) The last layer is a simple linear regression with a one dimensional output that gives the score.

Image Quality Assessment via Deep Learning 17

Image Quality Assessment (IQA)

• Performance Evaluationn Color Image Database TID2013

• 25 reference color images (512*368 pixels);

• 120 distorted versions of each reference image;

• 24 types of distortions, 125 images of each type;

• Totally 3000 images;

• MOS of each image is available.

[N. Ponomarenko, et al. EUVIP’13]

Image Quality Assessment via Deep Learning 18

Image Quality Assessment (IQA)

• Performance Evaluationn Scatter plots

Image Quality Assessment via Deep Learning 19

Image Quality Assessment (IQA)

• Performance Evaluationn Pearson linear correlation coefficient (PLCC),

n Spearman’s rank- order correlation coefficient (SRCC), and

n Kendall rank-order correlation coefficient (KRCC)

Image Quality Assessment via Deep Learning 20

Image Quality Assessment (IQA)

• Applications: IQA Guided CNNs Training

Image Quality Assessment via Deep Learning 21

Image Quality Assessment (IQA)

• Applications: GAN

Image Quality Assessment via Deep Learning 22

Image Quality Assessment (IQA)

• Applications: Compression Artifact Removal

Galteri, Leonardo, et al. “Deep Generative Adversarial Compression Artifact Removal." arXiv preprint arXiv:1704.02518 (2017).

Image Quality Assessment via Deep Learning 23

Contents

• Background

• Visual Quality Assessment (VQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions

Image Quality Assessment via Deep Learning 24

Photo Quality Assessment (PQA)

• What is Photo Aesthetic Quality?

Beautiful / Professional / Good Ugly / Amateurish / Bad

[Marchesotti et al. 2015]

Image Quality Assessment via Deep Learning 25

Photo Quality Assessment (PQA)

• Challengesn Aesthetic Principles

n Subjective PQA Mechanism

n Personalized

n Correlated with various image attributes (e.g. emotion, scene, semantic, style)

Image Quality Assessment via Deep Learning 26

Photo Quality Assessment (PQA)

• Research Groups

Prof. Tang Xiaoou, SeanFellow IEEE

Multimedia Laboratory

Xinmei TianAssociate Professor

Xin Lu

Image Quality Assessment via Deep Learning 27

Photo Quality Assessment (PQA)

• AVA database (250k images)n Ratings, Average ratings, Semantics, Styles

Image Quality Assessment via Deep Learning 28

Photo Quality Assessment (PQA)

• Crowd Opinion [Marchesotti et al. 2015]

Image Quality Assessment via Deep Learning 29

Photo Quality Assessment (PQA)

• Crowd Opinion [Marchesotti et al. 2015]

Image Quality Assessment via Deep Learning 30

Photo Quality Assessment (PQA)

• Crowd Opinion [Marchesotti et al. 2015]

Image Quality Assessment via Deep Learning 31

Photo Quality Assessment (PQA)

• Style

low depth-of-field, single salientobject and rule-of-thirds

[Marchesotti et al. 2015]

black and white

Image Quality Assessment via Deep Learning 32

PQA via Deep Learning

• Methodology

Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

PQA via CNNs

Single-column CNNs

Multi-column CNNs

Multi-task CNNs

Image Quality Assessment via Deep Learning 33

PQA via Deep Learning

• Single-column CNNsn CNNs trained on ImageNet

n Transferred CNNs

• Pretrain in the PQA task

• Fine-tuning in the binary classification task of photo aesthetic (good or bad)

Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

Image Quality Assessment via Deep Learning 34

PQA via Deep Learning

• Multi-column CNNsn global features + local features

n global features + attribute features

Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

Image Quality Assessment via Deep Learning 35

PQA via Deep Learning

• Multi-task CNNsn Correlated with various image attributes (e.g.

emotion, scene, semantic, style)

• Task 1: Aesthetic prediction

• Task 2: Semantic prediction

• Task n: …

Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

Image Quality Assessment via Deep Learning 36

PQA via Deep Learning

• Multi-task Multi-column CNNs Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

Image Quality Assessment via Deep Learning 37

PQA via Deep Learning

• A-lampn Adaptive Layout-Aware Multi-Patch

Image Quality Assessment via Deep Learning 38

PQA via Deep Learning

• A-lamp

Pipeline of attribute-graphs construction. (a) Salient objects (labeled by yellow bounding boxes) are first detected by a trained CNN, and regarded as local nodes. The dashed green bounding box denote the overall scene, which served as a global node. (b) Local and global attributes are extracted from these nodes to capture the object topology and the image layout. (c) Attribute-graphs are constructed and (d) concatenated into an aggregation layer.

Image Quality Assessment via Deep Learning 39

PQA via Deep Learning

• Performance

Y. Deng, C.-L. Chen, and X. Tang, “Image aesthetic assessment: An experimental survey,” 2016.

Image Quality Assessment via Deep Learning 40

PQA via Deep Learning

• Applications

n Enhancement

n Retargeting

n Retrieval

n Mobile APPs

Image Quality Assessment via Deep Learning 41

Image Enhancement

• EnhanceGAN

• Deng, Yubin, Chen Change Loy, and Xiaoou Tang. "Aesthetic-Driven Image Enhancement by Adversarial Learning." arXiv preprint arXiv:1707.05251(2017).

Image Quality Assessment via Deep Learning 42

Image Enhancement

• Creatism

• Fang, Hui, and Meng Zhang. "Creatism: A deep-learning photographer capable of creating professional work." arXiv preprint arXiv:1707.03491(2017).

A panorama (a) is cropped into (b), with saturation and HDR strength enhanced in (c), and with dramatic mask applied in (d).

Image Quality Assessment via Deep Learning 43

Contents

• Background

• Image Quality Assessment (IQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions

Image Quality Assessment via Deep Learning 44

Biometric Quality Assessment (BQA)

• Definitionn Quality of a biometric

sample is a measure of its efficiency in aiding recognition of an individual, ideally, irrespective of the recognition system in use.

Sample images of varying quality.

(a) Fingerprint, (b) iris (from WVU multimodal database), and (c) face (from SCface and CAS-PEAL face databases)

Image Quality Assessment via Deep Learning 45

Biometric Quality Assessment (BQA)

• Pipeline of a typical biometric system.

Image Quality Assessment via Deep Learning 46

Biometric Quality Assessment (BQA)

• Face

Image Quality Assessment via Deep Learning 47

Biometric Quality Assessment (BQA)

• Face: ID

Image Quality Assessment via Deep Learning 48

Biometric Quality Assessment (BQA)

• Four primary image features for BQA

Image Quality Assessment via Deep Learning 49

Biometric Quality Assessment (BQA)

• BQA via LightCNN

Image Quality Assessment via Deep Learning 50

Biometric Quality Assessment (BQA)

• Face recognition/identification/verification

Outline of the DeepFace architecture.

Image Quality Assessment via Deep Learning 51

Biometric Quality Assessment (BQA)

Image Quality Assessment via Deep Learning 52

Biometric Quality Assessment (BQA)

• Applications: Utilizing BQA for context switching

Image Quality Assessment via Deep Learning 53

Contents

• Background

• Image Quality Assessment (IQA)

• Photo Quality Assessment (PQA)

• Biometric Quality Assessment (BQA)

• Discussions