Method and devices for authenticating a user by image, depth, and thermal detection

An electronic device includes a two-dimensional imager, a three-dimensional imager, and a thermal sensor. One or more processors determine whether at least one image captured by the two-dimensional imager matches a first predefined criterion, whether at least one facial depth scan captured by the three-dimensional imager matches a second predefined criterion, and whether thermal energy detected by the thermal sensor matches a third predefined criterion. Touchless authentication of a person as an authorized user of the electronic device occurs when the at least one image matches the first predefined criterion, the at least one facial depth scan matches the second predefined criterion, and the thermal energy matches the third predefined criterion. Additional security factors, such as the expression of a predefined mien, can be used as well.