1. Adaptive Image and Video Retargeting Technique Based on Fourier Analysis Jun-Seong Kim, Jin-Hwan Kim, and Chang-Su Kim School of Electrical Engineering, Korea University, Seoul, Korea Reporter: Chia-Hao Hsieh Date: 20100316

2. Outline Introduction Methods Simulation results 2

3. Introduction OriginalScaledCroppedRetargeted 3

4. Introduction 4

5. Methods Partitioning Scaling distortions Adaptive scaling 5

6. Partitioning K = 10 in this work 6

7. Scaling distortions z[n]: a row signal of length l k in the kth strip Reduce the length by removing r k pixels to obtain a downsampled signal z d [n] The sampling rate is reduced by a factor of (1- (r k /l k ))π 7

8. Scaling distortions The signal should be lowpass- ltered with a cutoff frequency ω c = (1-(r k /l k ))π to avoid aliasing artifacts Scaling distortions (The energy of the lost high frequency components) Can be approximated by 8 Except for the dominant DC component A smaller s k makes the exponential function decrease more quickly

9. Scaling distortions Can be approximated by Scaling distortion of the kth strip: 9 Except for the dominant DC component

10. Adaptive scaling To minimize the sum of the distortions of strips R = W s W t Constrained optimization problem Can be solved by minimizing the Lagrangian cost function 10

11. Adaptive scaling 11

12. Extension to video retargeting Cut the volume into parallelepipeds along the time axis Each parallelpiped is scaled down spatially Partitioning of a video sequence for horizontal resizing. 12

13. Simulation Results 13

14. Simulation Results 14

15. Conclusions The proposed algorithm requires much less computations than the seam carving Excellent temporal coherence without jitter artifacts 15