Inspection of drilled features in objects

An apparatus for determining a depth of a feature formed in an object, the feature having been formed in the object by a cutting tool, the apparatus comprising:

• a camera configured to capture an image of the feature and a portion of the object proximate to the feature;
• and
• one or more processors operatively coupled to the camera and configured to:
• detect, in the image, an edge of the feature between the feature and a surface of the object;
• using the detected edge, calculate a diameter for a circle;
• acquire a point angle of the cutting tool;
• determine that a portion of the object proximate to the feature has curvature substantially equal to zero, is concave relative to the camera, or is convex relative to the camera;
• and,
• responsive to determining that a portion of the object proximate to the feature has curvature substantially equal to zero, using the diameter of the best fit circle and the acquired point angle, calculate a depth value for the feature;
• responsive to determining that a portion of the object proximate to the feature is concave relative to the camera, using the diameter of the circle and the acquired point angle, calculate the depth value for the feature;
• responsive to determining that a portion of the object proximate to the feature is convex relative to the camera, using the diameter of the circle and the acquired point angle, calculate the depth value for the feature.