| CPC G06T 5/50 (2013.01) [G06T 7/0002 (2013.01); H04N 23/67 (2023.01); G06T 2207/10148 (2013.01); G06T 2207/10152 (2013.01); G06T 2207/20216 (2013.01); G06T 2207/30168 (2013.01)] | 20 Claims |
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1. A metrology system, comprising:
an objective lens comprising an optical axis and configured to input image light arising from a workpiece and to transmit the image light along an imaging optical path;
a camera comprising a sensor array including pixels, wherein the camera is configured to receive image light transmitted along the imaging optical path and to provide images of the workpiece, wherein a focus position that corresponds to the focus of the images is configured to be variable along the optical axis;
a lighting configuration configured to provide light from a plurality of different lighting positions toward the workpiece, the plurality of lighting positions comprising at least first and second lighting positions;
one or more processors; and
a memory coupled to the one or more processors and storing program instructions that when executed by the one or more processors cause the one or more processors to at least:
control the lighting configuration and the camera to acquire a plurality of image stacks, the plurality of image stacks comprising at least first and second image stacks, wherein:
each image stack is acquired utilizing different corresponding workpiece lighting, including:
the first image stack is acquired utilizing first workpiece lighting which comprises light from the first lighting position; and
the second image stack is acquired utilizing second workpiece lighting which comprises light from the second lighting position;
each image stack includes a plurality of images of the workpiece for which each image corresponds to a different focus position along the optical axis; and
each image has associated pixel intensity values for which each pixel intensity value corresponds to a pixel position and the focus position of the respective image and for which the plurality of image stacks comprises a set of pixel intensity values for each pixel position and focus position with one pixel intensity value of the set coming from each image stack;
utilize the sets of pixel intensity values to determine a composite stack which includes one pixel intensity value for each corresponding pixel position and focus position, wherein at least some of the pixel intensity values of the composite stack are determined according to a glare reduction process which is configured to determine a corresponding pixel intensity value for the composite stack that is less than a maximum pixel intensity value of the corresponding set of pixel intensity values; and
determine focus curve data based at least in part on the pixel intensity values of the composite stack, wherein the focus curve data indicates three dimensional positions of a plurality of surface points on the workpiece.
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