A method and apparatus for evaluating an object having a wrinkle are provided. An array of receiving elements is configured such that only two receiving apertures are configured to receive at a given point in time. Energy is sent into the object using an array of transmitting elements. Reflected energy is received at the only two receiving apertures of the array of receiving elements in response to a portion of the energy being reflected off a plurality of layers in the object. A number of dimensions of a wrinkle in the object is determined based on the reflected energy received at the only two receiving apertures of the array of receiving elements.