Method and apparatus for detecting commercial variations in at least a portion of an at least partially transparent container. A light pattern in an angular domain is established from signals generated by a plurality of light sensors, wherein a point in the light pattern is generated by a signal from a corresponding portion of the light sensors and represents a light intensity corresponding to a particular reflection angle of a light ray reflected off the container. Different types of commercial variations in the container can be differentiated by analyzing the light pattern in the angular domain.