Abstract: An apparatus and method for inspecting skived glue, hemming and skew, and backfold of cartons by means of real time image comparison. The apparatus comprises channel sensors, means for measuring conveyor travel distance, a system controller coupled to the channel sensors, a memory for storing images, a processor coupled to the outputs of the system controller and the memory and a bad carton locator means. A known good carton is passed through the channel sensors and a reference synthetic image is stored in a memory. A test carton is passed through the channel sensors producing a real time image which is compared to the stored reference synthetic image for detecting defects.