Method and Device for Finding and Tracking Pairs of Eyes

Method for finding and subsequent tracking of the 3D coordinates of a pair of eyes in at least one face, comprising the following steps:

• a) Reception of image data comprising a sequence of at least one digital video signal from at least one image sensor;
• b) Finding eyes or tracking already found eyes in the image data;
• c) Determining the 3D coordinates of the found or tracked eyes;
• d) Assignment to the found or tracked eyes to form a pair of eyes;
• and
• e) Output of the 3D coordinates of the pair of eyes;
• where the process of finding eyes in the image data comprises the following steps:
• f) Identification of one or multiple faces in the image data;
• g) Determining the 3D coordinates of at least one identified face;
• h) Definition of a first search area on the identified face;
• and
• i) Finding at least one eye in the first search area;
• where the process of tracking already found eyes in the image data comprises the following steps:
• j) Definition of a second search area on the identified face;
• and
• k) Tracking the eyes of the pair of eyes in the second search area;
• wherein the process of finding at least one eye in the first search area comprises the following steps:
• l) Computing an expected size of a part of the eye depending on the distance of the identified face from the image data providing image sensor;
• m) Computing a greyscale value as a threshold for a segmentation in the first search area depending on the distance of the identified face from the image data providing image sensor;
• n) Pre-processing the first search area aiming to improve the contrast;
• o) Segmentation of the first search area after the pre-processing;
• p) Computing one or multiple combined regions in the segmented first search area, where the combined region is a collection of adjacent pixels with at least approximately identical greyscale value;
• q) Determining a size of each computed combined region;
• and
• r) Comparing the expected size of the part of the eye with the determined size of the combined region, where the combined region represents a found eye if the determined size of the combined region at least approximately corresponds with the expected size of the part of the eye.