Field curvature model for confocal imaging apparatus with curved focal surface

A method comprising:

• receiving, by a processor, intensity measurements generated by a plurality of pixels of a detector of a confocal imaging apparatus, wherein each pixel of the plurality of pixels provides intensity measurements for an associated returning light beam from an array of returning light beams that have been reflected off of an imaged three dimensional object, and wherein each returning light beam of the array of returning light beams is associated with a point of the three dimensional object;
• determining, for each pixel of the plurality of pixels, a focusing setting of the confocal imaging apparatus that provides a maximum measured intensity;
• determining, for each pixel of the plurality of pixels, a depth of a point of the three dimensional object associated with the pixel that corresponds to the determined focusing setting;
• adjusting, by the processor, the depth of at least one point of the three dimensional object based on applying the determined focusing setting for the pixel associated with the at least one point to a field curvature model to compensate for a non-flat focal surface of the confocal imaging apparatus;
• and
• determining, by the processor, a shape of the three dimensional object based at least in part on the adjusted depth.

A non-transitory computer readable storage medium having instructions that, when executed by a processor, cause the processor to perform operations comprising:

• receiving intensity measurements generated by a plurality of pixels of a detector of a confocal imaging apparatus, wherein each pixel of the plurality of pixels provides intensity measurements for an associated returning light beam from an array of returning light beams that have been reflected off of an imaged three dimensional object, and wherein each returning light beam of the array of returning light beams is associated with a point of the three dimensional object;
• determining, for each pixel of the plurality of pixels, a focusing setting of the confocal imaging apparatus that provides a maximum measured intensity;
• determining, for each pixel of the plurality of pixels, a depth of a point of the three dimensional object associated with the pixel that corresponds to the determined focusing setting;
• adjusting, by the processor, the depth of at least one point of the three dimensional object based on applying the determined focusing setting for the pixel associated with the at least one point to a field curvature model to compensate for a curved focal surface of the confocal imaging apparatus;
• and
• determining a surface topology of the three dimensional object based at least in part on the adjusted depth.