Methods and apparatus for inspection of lines embedded in highly textured material

A method for programming a machine vision inspection system to inspect a workpiece having a highly-textured or low-contrast surface and having at least one line to be determined present in or on the highly-textured or low-contrast surface, the at least one line to be determined arranged in an arrangement that is characteristic of that type of workpiece, the method comprising:

• capturing a workpiece image of at least the portion of the workpiece having the highly-textured or low-contrast surface having the at least one line to be determined;
• determining at least one image enhancement process for processing the captured workpiece image to provide an enhanced image that enhances at least one characteristic of at least one of the at least one line to be determined;
• generating at least one part program instruction operable to perform the determined image enhancement process;
• transforming the enhanced image using a transform that nominally generates a 2-dimensional set of values that include local extrema nominally corresponding to probable individual lines, the local extrema including proper-polarity local extrema having a polarity corresponding to the at least one line to be determined, the two dimensional coordinates of the local extrema usable to define the corresponding individual lines;
• generating at least one part program instruction operable to perform the transforming process to generate the 2-dimensional set of values;
• defining at least one line constraint corresponding to the arrangement that is characteristic of that type of workpiece;
• determining a process for determining the at least one line to be determined based on the 2-dimensional set of values and at least partially on at least one defined line constraint;
• generating at least one part program instruction operable to perform the process for determining the at least one line to be determined based at least partially on at least one defined line constraint;
• storing a set of part program instructions including at least the part program instructions operable to perform at least the determined image enhancement process, the transforming process to generate the 2-dimensional set of values, and the process for determining the at least one line to be determined based at least partially on at least one defined line constraint, the set of part program instructions at least operable to determine the at least one line to be determined on a workpiece of that type.

A method for operating a machine vision inspection system to inspect a workpiece having a highly-textured or low-contrast surface and having at least two lines to be determined present in or on the highly-textured or low-contrast surface, the at least two lines to be determined arranged in an arrangement that is characteristic of that type of workpiece, the method comprising:

• capturing a workpiece image of at least the portion of the workpiece having the highly-textured or low-contrast surface having the at least two lines to be determined;
• processing the captured workpiece image to provide an enhanced image that enhances at least one characteristic of the at least two lines to be determined;
• transforming the enhanced image using a transform that nominally generates a 2-dimensional set of values that include local extrema nominally corresponding to probable individual lines, the local extrema including proper-polarity local extrema having a polarity corresponding to the at least two lines to be determined, the two dimensional coordinates of the local extrema usable to define the corresponding individual lines;
• analyzing the 2-dimensional set of values to select at least two proper-polarity local extrema such that the selected at least two local proper-polarity extrema comprise most extreme-valued proper-polarity local extrema that also correspond to lines arranged in the arrangement that is characteristic of that type of workpiece;
• and
• determining the at least two lines to be determined based on the two dimensional coordinates of the selected at least two local extrema.

A method for programming a machine vision inspection system to inspect a workpiece having a highly-textured or low-contrast surface and having at least two lines to be determined present in or on the highly-textured or low-contrast surface, the at least two lines to be determined arranged in an arrangement that is characteristic of that type of workpiece, the method comprising:

• capturing a workpiece image of at least the portion of the workpiece having the highly-textured or low-contrast surface having the at least two lines to be determined;
• determining an image enhancement process for processing the captured workpiece image to provide an enhanced image that enhances at least one characteristic of the at least two lines to be determined;
• generating at least one part program instruction operable to perform the determined image enhancement process;
• transforming the enhanced image using a transform that nominally generates a 2-dimensional set of values that include local extrema nominally corresponding to probable individual lines, the local extrema including proper-polarity local extrema having a polarity corresponding to the at least two lines to be determined, the two dimensional coordinates of the local extrema usable to define the corresponding individual lines;
• generating at least one part program instruction operable to perform the transforming process to generate the 2-dimensional set of values;
• determining a process for analyzing the 2-dimensional set of values to select at least two proper-polarity local extrema such that the selected at least two proper-polarity local extrema comprise most extreme-valued proper-polarity local extrema that also correspond to lines arranged in the arrangement that is characteristic of that type of workpiece;
• generating at least one part program instruction operable to perform that process for analyzing the 2-dimensional set of values to select the at least two proper-polarity local extrema that comprise the most extreme-valued proper-polarity local extrema that also correspond to lines arranged in the arrangement that is characteristic of that type of workpiece;
• and
• storing a set of part program instructions including at least the part program instructions operable to perform at least the determined image enhancement process, the transforming process to generate the 2-dimensional set of values and the process for analyzing the 2-dimensional set of values to select at least two proper-polarity local extrema that comprise the most extreme-valued proper-polarity local extrema that also correspond to lines arranged in the arrangement that is characteristic of that type of workpiece, the set of part program instructions at least operable to determine the at least two lines to be determined on a workpiece of that type based on the selected at least two proper-polarity local extrema that comprise the most extreme-valued proper-polarity local extrema that also correspond to lines arranged in the arrangement that is characteristic of that type of workpiece.