Abstract: A product discrimination system using an off-loading conveyor with rotatably mounted bow tie rollers to convey product units past a sensing station. The sensing station includes four receptors arranged along the conveying path for sensing the physical attributes of products. Between the receptors are friction surfaces which contact the rollers to rotate same and, in turn, rotate the product units on the conveyor. During sensing, the product units are stationary. Ahead of the sensing station, an elongate friction surface is positioned to rotate the rollers. The four views of each product unit may be independently analyzed or may be compared. A ratio of the greatest and the least of the readings may be used to grade product units. The greatest or least may be used independently to grade or may both be discarded and an average taken of the remaining readings to determine an average of an attribute.