Pellet inspection system

A method of inspecting cylindrically configured pellets for surface defects comprising the steps of

• generating a two-dimensional digital image having a two-dimensional array of digital values representative of the peripheral surface of a known pellet,
• determining an average value for the array of digital values in the two-dimensional digital image,
• determining a threshold standard from the average value,
• generating a set of discrete digital values representative of an unknown pellet surface,
• comparing the set of digital values to the threshold standard,
• identifying groups of digital values representative of adjacent locations on the surface of the pellet having values greater or less than the threshold standard, and
• rejecting an unknown pellet when the number of digital values having a value greater or less than the threshold standard exceeds a certain number,
• while also identifying the digital values corresponding to the edges of the unknown pellet, calculating the area circumscribed by the edges of the pellet and rejecting the pellet if the calculated value is greater than a predetermined amount.

An apparatus for inspecting cylindrically configured pellets for surface defects comprising

• means for axially transporting a pellet along a path of travel through an inspecting station while rotating the pellet along its longitudinal axis, said transporting means including first and second horizontally positioned substantially parallel and longitudinally extending pellet support rolls, said rolls being transversely spaced a distance from each other less than the diameter of a pellet to be transferred, drive means connected to said pellet support rolls for rotating each of said rolls to impart a net rotation to the pellets, means positioned between the spaced rolls for engaging a pellet and moving the pellet between the spaced pellet support rolls, said moving means further including an endless loop pellet transport chain positioned adjacent and below one of said pellet support rolls, said pellet transport chain including a plurality of spaced, laterally extending arms having dogs thereon, said endless loop pellet transport chain being positioned so that during movement of said chain, said dogs are moved longitudinally between said rolls for engaging and moving a pellet supported thereon,
• line scan camera means positioned at said inspection station for scanning axially the pellet surface,
• control means comprising
• a) receiving means for receiving signals received from said line scan camera means to a predetermined standard and identifying groups of digital values representative of adjacent locations on the surface of the pellet having values greater or less than the predetermined standard, and
• reject means responsive to said control means for rejecting defective pellets.