Method of optimizing target quantities for optical precision measurement and apparatus therefor

A precision measuring apparatus for measuring workpieces, the precision measuring apparatus comprising:

• means for obtaining ancillary parameters from image data and deriving control data for influence quantities;
• means for determining a weighted summation of the individual ones of said ancillary parameters for a target function to be optimized wherein said target function includes a plurality of focus values each being different from the other;
• and
• means for determining all ancillary parameters in such a manner that they have a like extreme of the functional dependency of the influence quantities.

A method for optimizing target quantities for optical precision measuring wherein ancillary parameters are obtained from image data of a workpiece to be measured and wherein control data is derived from said ancillary parameters for influence quantities of these target quantities, the method comprising deriving the control data with the steps of:

• determining the courses of the ancillary parameters in dependence upon at least one influence quantity and determining the courses of the ancillary parameters so that the courses have a like extremum of the functional dependency of the influence quantity;
• determining a total course of the ancillary parameters in dependence upon the influence quantity via weighted summation of the courses of the ancillary parameters;
• determining an extremum of the total course of the ancillary parameters;
• and,
• determining the corresponding value of the influence quantity at the site of the specific extremum as control datum for the influence quantity.

An optical precision measuring apparatus comprising:

• an image recording device;
• an image processing device connected to said image recording device;
• and,
• said image processing device functioning to obtain ancillary parameters for optimizing target quantities of a measuring sequence of a workpiece to be measured and to derive control data from said ancillary parameters for influence quantities of said target quantities by performing the following steps:
• determining the courses of the ancillary parameters in dependence upon at least one influence quantity with the courses of the ancillary parameters being so determined that the courses have a like extremum of the functional dependency from the influence quantity;
• determining a total course of the ancillary parameter in dependence upon the influence quantity via a weighted summation of the courses of the ancillary parameters;
• determining an extremum of the total course of the ancillary parameters;
• and,
• determining the corresponding value of the influence quantity at the site of the determined extremum as a control data for the influence quantity.