Calibration reticle for measuring microscopes

A method of calibrating a measuring microscope having a filar eyepiece, said method comprising:

• placing a reticle containing a calibration pattern in said field of view of said microscope and at least substantially in focus, said calibration pattern comprising a plurality of areas of a first contrast value, a plurality of areas of a second contrast value, a plurality of areas of a third contrast value and a plurality of areas of a fourth contrast value, said second contrast value different from said first contrast value, and said fourth contrast value different from said third contrast value, said areas of said first, second, third and fourth contrast values arranged to establish within said calibration reticle at least two parallel, straight, calibration reference lines spaced from each other by a known distance, each said calibration reference line defined with respect to at least two boundary lines from which it is equidistant, a first said boundary line defined by a portion of the boundary between an area of said first contrast value and an area of said second contrast value, a second said boundary line defined by a portion of the boundary between an area of said third contrast value and an area of said fourth contrast value, said first boundary line defined by a straight line portion of a boundary between (1) a first localized region which has said first contrast value, at least substantially all of said first localized region being on a first side of said given calibration reference line and (2) a second localized region which has said second contrast value, at least substantially all of said second localized region being on a second side of said given calibration reference line, and said second boundary line defined by a straight line portion of a boundary between (1) a third localized region which has said third contrast value, at least substantially all of said third localized region being on said second side of said given calibration reference line and (2) a fourth localized region which has said fourth contrast value, at least substantially all of said fourth localized region being on said first side of said given calibration reference line;
• selecting as a first calibration reference position a first calibration reference line established by said calibration pattern;
• selecting as a second calibration reference position a second calibration reference line established by said calibration pattern, said second calibration reference line being diffeent than said first calibration reference line;
• while viewing said calibration pattern through said microscope:
• centering the hairline means of said filar eyepiece in said first calibration reference position to align said hairline means with said first calibration reference line;
• translating said hairline means relative to the image of said calibration pattern and centering said hairline means in said second calibration reference position to align said hairline means along said second calibration reference line;
• and
• comparing the distance transversed during said translating as measured by said microscope against the known distance actually traversed as defined by said calibration pattern in order to establish the actual calibration of said microscope.

A method of calibrating an image-shearing measuring microscope which generates relatively displaceable first and second images of an object in its field of view, said method comprising:

• placing a reticle containing a calibration pattern in said field of view of said microscope and at least substantially in focus, said calibration pattern comprising a plurality of areas of a first contrast value and a plurality of areas of a second contrast value, said second contrast value different from said first contrast value, said areas of said first contrast value interspersed with said areas of said second contrast value;
• said areas of said first and second contrast value arranged to establish within said calibration reticle at least two parallel calibration reference lines spaced from each other by a known distance;
• each said calibration reference line defined with respect to at least two boundary lines from which it is equidistant;
• each said boundary line defined by a portion of the boundary between an area of said first contrast value and an area of said second contrast value;
• said at least two boundary lines with respect to which a given calibration reference line is defined comprising (a) a first boundary line defined by a portion of a boundary between (1) a first localized region which has said first contrast value, at least substantially all of said first localized region being on a first side of said given calibration reference line and (2) a second localized region which has said second contrast value, at least substantially all of said second localized region being on the second side of said given calibration reference line, and (b) a second boundary line defined by a portion of a boundary between (1) a third localized region which has said first contrast value, at least substantially all of said third localized region being on said second side of said given calibration reference line and (2) a fourth localized region which has said second contrast value, at least substantially all of said fourth localized region being on said first side of said given calibration reference line;
• selecting as a first calibration reference object means an area of said first contrast value in said first image of said calibration pattern;
• selecting as a first calibration reference position an area of said first or second contrast value in said second image of said calibration pattern,
• selecting as a second calibration reference object means an area of said first or second contrast value in one of said first or second images;
• selecting as a second calibration reference position an area of said first or second contrast value in the other of said first and second images of said calibration pattern;
• while viewing said images through said microscope;
• centering said first calibration reference object means in said first calibration reference position to align a first calibration reference line in said first image along a second calibration reference line in said second image;
• translating said first image relative to said second image and centering said second calibration reference object means in said second calibration reference position to align a third calibration reference line in said first image along a fourth calibration reference line in said second image, either said third calibration reference line being different than said first calibration reference line or said fourth calibration reference line being different than said second calibration reference line, or both;
• and
• comparing the distance traversed during said translating as measured by said microscope against the known distance actually traversed as defined by said calibration pattern in order to establish the actual calibration of said microscope.