1. Electrical & Computer Engineering Dept. University of Patras, Patras, Greece Evangelos Skodras Nikolaos Fakotakis

2. Eyes represent the most distinctive landmarks of the human face The position and movements of eyes are a significant source of information about the cognitive and affective state of human beings: eyes hold a key role in expressing interest, intention and attention Importance of eye localization University of Patras 1/13

3. 3 A wide range of applications… University of Patras Non-glasses type 3D technologies Monitoring of drivers’ attention and vigilance Visual attention analysis Interactive gaze-based interfaces for disabled people 2/13

4. 4 Why hasn’t it been solved yet? University of Patras Completely unobtrusive eye localization with remotely located passive sensors (cameras) Low resolution, inexpensive imaging devices (e.g. webcams, pinhole cameras) Accurate and robust detection for human-machine interaction applications even in outdoor environments Requirements posed: Active sensors or dedicated hardware 3/13

5. 5 Great variability in shape, color, eye state, head pose and ethnicity Imaging conditions such as lighting and camera characteristics have a strong influence on how the eyes appear in the image Low resolution or compressed images derived from inexpensive devices Occlusions caused by hair, glasses, shadows and reflections Challenges of remote passive sensors University of Patras 4/13

6. What has been used 1.Appearance based Methods 2.Feature based Methods 5/13 Incorporate eye knowledge implicitly They generally require a large amount of training data and powerful non-linear algorithms in order to learn the high variability of eyes High accuracy in detecting the eye area Fail to provide an accurate detection of the eye center Explicit use of the a priori eye knowledge in order to derive features such as shape, geometry, color and symmetry Geometrical information of edges Parametric models (e.g. deformable templates) Circular shape modeling (Hough, Starburst, Integrodifferential) Symmetry operators …

7. Proposed Method University of Patras o Based upon a synergy of color and radial symmetry Color distribution of the eye area is significantly different to its surroundings Iris and pupil are characterized by radially symmetric brightness patterns Simple – no machine vision required Efficient – 0.12 sec for a 240 x 320 color image (Matlab implementation) Robust – occlusions, eye state, head pose, lighting changes Accurate – for human computer interaction applications Low-cost – using a standard webcam or pinhole camera 6/13

8. University of Patras Eye Map Construction Cb 2 Cr 2 Y Dilated EyeMapC Y EyeMapC Eroded EyeMapI / 7/13

9. Gradient - based interest operator which detects points of high radial symmetry Fast Radial Symmetry Transfrom University of Patras Determines the contribution each pixel makes to the symmetry of pixels around it The contribution of every orientation is computed in a single pass over the image 8/13

10. Proposed System Overview University of Patras + EyeMapI YS luminance S EyeMapI 9/13

11. University of Patras Quantitative Results Method Accuracy d n ≤ 0.05d n ≤ 0.1d n ≤ 0.25 Proposed Method 87.94 %94.26 %97.45 % Yang et al.68.72 %81.56 %96.45 % Valenti et al. 56.54 %84.69 %97.92 % Method Accuracy d n ≤ 0.05d n ≤ 0.1d n ≤ 0.25 Proposed Method 99.43 %99.54 %99.66 % Yang et al.98.16 %98.39 %99.08 % Valenti et al. 89.81 %98.59 %99.88 % GTAV Caltech 10/13

12. Qualitative Results

13. University of Patras Low computational complexity which allows real time performance with a proper C or hardware implementation The use of color information (rarely investigated in literature for this purpose) contributes significantly for precise localization High accuracy rates, outperforming existing methods, especially in low-resolution images Future work Correlate the level of attention of a driver (gaze estimation) with the danger of an impeding collision (vehicle detection and braking recognition). Conclusions12/13

14. University of Patras 13/13

15. Thank you for your attention! evskodras@upatras.gr