Method and apparatus for inspection of spherical surfaces

An apparatus for inspection of spherical surfaces, the apparatus comprises

• a first stand for holding an object with a spherical surface or curved surface for inspection,
• an apparatus head,
• a second stand for holding the apparatus head,
• and an electronic control and data processing system,
• wherein
• the first stand includes a rotary table configured to rotate the object about a rotation axis and to align the object such that the center of curvature of the surface for inspection is on the rotation axis,
• the apparatus head is configured to illuminate the surface for inspection with a beam of electromagnetic radiation that spins about a spin axis and to measure the electromagnetic radiation scattered on the surface for inspection,
• the second stand holds the apparatus head in front of the surface for inspection and directs the spin axis perpendicular to the surface for inspection so that the beam of electromagnetic radiation illuminates the surface for inspection with a spinning beam spot, and
• the electronic control and data processing system continuously obtains the first stream of data about the angular position of the spinning beam spot with respect to the spin axis, obtains the second stream of data about the angle of rotation of the object on the rotary table, obtains the third stream of data about the measured characteristic parameters of the radiation scattered on the surface for inspection, determines instantaneous coordinates of the beam spot on the surface for inspection based on the information in the first stream of data and the second stream of data, and synchronously records the data about the measured radiation scattered on the surface for inspection and the corresponding instantaneous coordinates of the beam spot on the surface for inspection.