A comparison of Gabor filter methods for automatic detection of facial landmarks

This paper presents a systematic analysis of Gabor filter banks for detection of facial landmarks (pupils and philtrum). Sensitivity is assessed using the A´ statistic, a non-parametric estimate of sensitivity independent of bias commonly used in the psychophysical literature. We find that current Gabor filter bank systems are overly complex. Performance can be greatly improved by reducing the number of frequency and orientation components in these systems. With a single frequency band, we obtained performances significantly better than those achievable with current systems that use multiple frequency bands. Best performance for pupil detection was obtained with filter banks peaking at 4 iris widths per cycle and 8 orientations. Best performance for philtrum location was achieved with filter banks with 5.5 iris widths per circle and 8 orientations.