a framework for photo-quality assessment and enhancement based on visual aesthetics subhabrata...
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A Framework for Photo-Quality Assessment and
Enhancement based on Visual Aesthetics
Subhabrata Bhattacharya Rahul Sukthankar Mubarak Shah
Introduction
Assessing the quality of photographs is challenging .
Experienced photographers adhere to several rules of composition .
Rule of Thirds
Visual Weight Balance
In a well composed image the visual weights of different regions satisfy the Golden Ratio .
Visual Weight Balance
Sea
Sky
k
~1.618k
Introduction
In this paper, will use these two rules to assess an image .
Formulate photo quality evaluation as a machine learning problem .
User Survey
15 participants were asked to assign integer rank from 1 to 5.
Each user was asked to rank no more than 30 images.
Generate single ground truth for each image (Fa).
Aesthetic Feature
Extract a relative foreground position feature for images with single-foreground compositions.
A visual weight ratio feature for photographs of seascapes or landscapes.
Defined as the normalized Euclidean distance between foreground’s mass to each four stress points.
Relative foreground position
The ratio of the sky region, to that in the support region ( ground or sea).
Visual weight ratio
Yg
Yk
Learning and Prediction
We use SVR to learn the mappings.
150 random images for training and resting for testing.
Enhancing Composition
Relocate the foreground object to increase the predicted appeal factor.
Better balancing the visual weights of the sky and support region.
Semantic Segmentation
Input ImageGeometric
Context Classifier*
*D. Hoiem, A.A. Efros, and M. Hebert, "Geometric Context from a Single Image", ICCV 2005
Sky
Support
Post Processin
gHorizon
Segmented
Foreground
Optimal object placement
Support Neighborhoo
d
s.t. neighbors stay “like neighbors”
+Intensity Term Gradient Term
Inpainting Foreground Hole
Yunjun Zhang. Jiangjian Xiao. Mubarak Shah, “Region Completion in a Single Image”, EUROGRAPHICS 04
Inpaint Hole
Balancing visual weights
Yk
Yg
Ratio of Current extents
Yk +h
Yg
h = vertical extent of the balanced image