Apparatus and process for inspecting print material

A method of inspecting print article comprising:

• creating a reference template from at least one reference image by calculating a reference address for each pixel data of said reference template, said calculating step comprising the steps of:
• multiplying a classification value of each pixel data by twice a gray scale range;
• center offsetting the result of said multiplying step by adding said gray scale range to said result;
• and
• adjusting said center offsetting step result with a reference pixel intensity value for each of said pixel data;
• storing said reference template;
• comparing each pixel intensity of a target image to a corresponding pixel data stored in said reference template;
• using the result of said comparing step as an index to a look-up table containing the predetermined flaw severity codes;
• reading an entry of said look-up table at said look-up table index to obtain a flaw severity code of said pixel data in said target image;
• aggregating the occurrences of said flaw severity codes in said target image;
• and
• comparing said aggregated flaw occurrences to at least one threshold value to determine the acceptability of said target image.

A program product comprising:

• a computer usable medium having computer readable program code means embodied therein for detecting pattern flaws, said computer readable program code means in said program product comprising:
• computer readable first program code means for causing the computer to effect creating a reference template from at least one reference image by calculating a reference address for each pixel data of said reference template, said calculating step comprising the steps of:
• multiplying a classification value of each pixel data by twice a gray scale range;
• center offsetting the result of said multiplying step by adding said gray scale range to said result;
• and
• adjusting said center offsetting step result with a reference pixel intensity value for each of said pixel data;
• computer readable second program code means for causing the computer to effect storing said reference template;
• computer readable third program code means for causing the computer to effect comparing each pixel intensity of a target image to a corresponding pixel data stored in said reference template;
• computer readable fourth program code means for causing the computer to effect using the result of said comparing step as an index to a look-up table containing predetermined flaw severity codes;
• computer readable fifth program code means for causing the computer to effect reading an entry of said look-up table at said look-up table index to obtain a flaw severity code of said pixel data in said target image;
• computer readable sixth program code means for causing the computer to effect aggregating the occurrences of said flaw severity codes in said target image;
• and
• computer readable seventh program code means for causing the computer to effect comparing said aggregated flaw occurrences to at least one threshold value and determining the acceptability of said target image.