Method and apparatus for industrial identification mark verification

Abstract

The invention provides methods and apparatus for analysis of images of direct part mark identification codes to measure and assess a print quality. Methods to assess the quality of a direct part mark identification code are presented that provide diagnostic information of a code that cannot be assessed using verification methods that require the results of a valid decoding step.

What is claimed is: 
     
         1 . A method for verifying a direct part mark inspection code, the method comprising:
 acquiring an image of the code;   attempting to decode the code using the image;   locating the code in the image if the attempt to decode the code is unsuccessful to provide a code location; and   measuring aspects of a mark quality using the image and the code location in the image.   
     
     
         2 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a quiet zone of the code in the image. 
     
     
         3 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a clocking pattern of the code in the image. 
     
     
         4 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a matrix size of the code in the image. 
     
     
         5 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a matrix size of the code in the image. 
     
     
         6 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a symbol separability test. 
     
     
         7 . The method according to  claim 1  wherein the step of measuring aspects of a mark quality comprises evaluating a module separability test. 
     
     
         8 . The method according to  claim 1  wherein the code is a symbol marked directly on an object. 
     
     
         9 . The method according to  claim 8  wherein the code is a data matrix. 
     
     
         10 . A method for verifying a direct part mark inspection code, the method comprising:
 acquiring an image of the code;   attempting to locate the code in the image;   attempting to decode the code using the image; and   measuring at least one aspect of a mark quality using the image of the code if the attempt to decode the code is unsuccessful.   
     
     
         11 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a quiet zone of the code in the image. 
     
     
         12 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a clocking pattern of the code in the image. 
     
     
         13 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a matrix size of the code in the image. 
     
     
         14 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a matrix size of the code in the image. 
     
     
         15 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a symbol separability test. 
     
     
         16 . The method according to  claim 10  wherein the step of measuring at least one aspect of a mark quality comprises evaluating a module separability test. 
     
     
         17 . An apparatus for verifying a direct part mark inspection code, the apparatus comprising:
 means for acquiring an image of the code;   means for attempting to decode the code using the image;   means for locating the code in the image if the attempt to decode the code is unsuccessful to provide a code location; and   means for measuring at least one aspect of a mark quality using the image and the code location.