The feasibility of a human face identification system using isodensity lines is demonstrated through experimental investigation. Isodensity lines are the boundaries of constant gray level areas obtained by quantizing a facial image. Utilization of these lines has the following advantages: (1) The technique is algorithmically and computationally simple to implement, both in hardware and in software. (2) Significant 3D structures can be reflected in the description of the face. (3) High discrimination accuracy is achieved, even for faces with spectacles or with thin bears (stubble). This system consists of a delineation of isodensity lines and a matching process. Extraction of the facial area is very easily put into practice by using a isodensity lines to represent the contour lines of the face. The matching process consists of template matching (global matching) and local compactness matching (fine matching) of registered and input isodensity lines. Experimental results show a 97.7% accuracy in matching 44 pairs of the same persons and a 100% accuracy in discriminating between 1892 pairs of different persons, including men with glasses or thin beards and women with or without make-up.