Apparatus and method for detecting surface defects on a workpiece such as a rolled/drawn metal bar

A system for imaging an elongated bar extending along a longitudinal axis, said system comprising:

• an image acquisition assembly including n digital cameras, where n is an integer 3 or greater, having a combined field of view configured to image a first predetermined width, taken with respect to said longitudinal axis, over a circumference of a surface of said bar to define an image belt, said image acquisition assembly being further configured to produce image data corresponding to said image belt;
• a light line assembly configured to project a light line belt having a second predetermined width, taken with respect to said longitudinal axis, onto the surface of said bar surface, said light line assembly being disposed relative to said image acquisition assembly such that said image belt is within said light line belt, said light line assembly being further configured such that a light intensity is substantially uniform along said image belt;
• a computing unit coupled to said image acquisition assembly configured to receive image data for a plurality of image belts acquired by said image acquisition assembly as said bar moves along said longitudinal axis, said computing unit being further configured to process said image data to detect predetermined surface features of said bar, said detected features including surface defects, said computing unit being further configured to maintain a record of said detected defects including (i) a respective location of each detected defect relative to a start location of said bar and (ii) a respective notation as to the nature, such as a size, a shape, or a contrast level of each detected defect.

A method of imaging a metal bar extending along a longitudinal axis, said method comprising the steps of:

• (A) projecting a light line belt having a first predetermined width onto the metal bar;
• (B) capturing an image belt having a second predetermined width located within the light line belt;
• (C) moving the metal bar along the longitudinal axis;
• (D) repeating steps (A) and (B) to obtain an image of a surface area of the metal bar;
• (E) analyzing the image for features in accordance with predefined criteria.