Automatic color and grain sorting of materials

A system for automatically color and grain sorting materials includes a pair of color cameras positioned to view the top and bottom faces, respectively, of each part. A computer analyzes the data from the top and bottom cameras, and also controls the voltage on the input line to each camera. Camera controllers accept analog data from the camera heads and digitize it so that the information can be passed to the computer for analysis. A white target inserted into the field of view of each camera allows the computer to collect the data needed to do ''shading compensation'' on the collected color image data. Three basic categories of algorithms are used in the sorting system in accordance with the present invention: (1) training algorithms used to teach the system to identify the color and grain classes that are to be used during the sorting process, (2) real-time operation algorithms which perform the color and grain sorts with parts moving through the system at the desired throughput rate, and (3) utility algorithms which allow operators to display images, perform system tests, etc. In the training and sorting algorithms, the computer produces a black/white histogram of a part face based on the data analysis, and applies a character mark algorithm to the black/white histogram to find a threshold value for eliminating the effects of character marks from the color and grain classification and sorting of the part.