1. Understanding and Predicting Image Memorability at a Large Scale A. Khosla, A. S. Raju, A. Torralba and A. Oliva International Conference on Computer Vision (ICCV), 2015 Presented by Yue Guo yueguo@cs.unc.edu

2. Memorable ~90% Average ~70% Forgettable ~40% Isola et al (2014). PAMI Large difference in image memorability

3. Main Contributions 1.Built LaMem, the largest annotated image memorability dataset to date; 2.Achieved the state-of-the-art performance on the LaMem using Convolutional Neural Networks (CNNs); 3.Provided a method to perform image memorability manipulation

4. LaMem It contains 60,000 images from MIR Flickr, AVA dataset, affective images dataset (consisting of Art and Abstract datasets), image saliency datasets (MIT1003 and NUSEF), SUN, image popularity dataset, Abnormal Objects dataset, aPascal dataset etc. Memorability score

5. Procedure The vigilance repeats ensured that workers were paying attention. About 27 times larger than the previous dataset. Model memorability with time delay between images by a log- linear relationship. Obtained 80 scores per image on average, resulting in a total of about 5 million data points.

6. Math Memorability as a function of time interval Object function Solve this optimization problem using Expectation–maximization (EM)

7. Findings 1.Popularity: The popularity scores of the most memorable images are statistically higher than those of the others 2.Saliency Images that are more memorable tend to have more consistent human fixations 3.Emotion Images that evoke negative emotions such as anger and fear tend to be more memorable than those portraying positive ones 4.Aesthetics The aesthetic score of an image and its memorability have little to no correlation.

8. CNNs AlexNet, pre-trained on ILSVRC 2012 and Places dataset, fine-tuned with a Euclidean loss layer as the last layer, called MemNet. Rank correlation Human consistency on LaMem is 0.68

9. Analysis Visualization the CNN features after fine-tuning The memorability heat maps

10. Subjective judgments do not predict image memorability Memorable Forgettalbe Think memorable Think forgettable (89%)(86%) (44%)(40%) Isola et al (2011). Neural Information Processing Systems (NIPS)