Iris Detection Using Deformable Template.

Instructions:

• Select initial circle by clicking twice on the image.
• Run the template and watch the circle lock in on the iris.

To find the iris in the entire face we look for the following features

1. Darkest circular region in the entire image
2. Circle radius close to expected value (~15 pixels in this case)
3. Circle radius not too small
4. Circle is not on the peripheral
5. Bright fringe along the peripherals of the dark circle

1. The deformable template occasionally settles on the shadows, since they also contain the darkest circular regions in the image. This dilemma is partially taken care of by Strategy #5. Shadows surrounded by bright areas still cause problems.
2. Glitters in the eye sometimes cause the template to settle on just a portion of the iris, since we are looking for the darkest circular region.
3. For certain initial circles, the template settles on the eyebrow, due to Strategy #5.
4. Sometimes the corner of the eye is preferred over the iris itself. Corners of the eye are dark regions with the white apple of the eye and the bright nose on the peripherals.