Method and apparatus for three-dimensional imaging using laser illumination interferometry

A method for determining a range dimension of an object utilizing multiple wavelength interferometry to form an image of the object, the method comprising:

• (a) developing a discernible two-dimensional image from an interference pattern for each of a plurality of wavelengths by utilizing a lens to perform a two-dimensional transform of the interference pattern while directing the pattern on a two-dimensional detector array which is positioned in an image plane of the lens;
• (b) collecting a complex value from the interference pattern directed by the lens onto the detector array for each of the plurality of wavelengths at each of a plurality of selected points on the object and developing a phase value from the complex value;
• (c) selecting at least one reference point on the object;
• (d) determining a difference between the phase values of each reference point and an associated ideal phase value for each of the wavelengths at that reference point;
• (e) establishing a phase correction vector from the difference determined in (d), wherein the phase correction vector is a complex conjugate of the difference between the phase values of each reference point and its associated ideal phase value for each of the wavelengths at that reference point;
• (f) establishing a corrected value for each of the selected points by adding the phase correction vector to the complex values of each of the selected points;
• (g) performing a Fourier transform on a series of the corrected values for each of the selected points to yield a range profile for each selected point;
• (h) determining a peak value from each of the range profiles to determine the range dimension;
• and
• (i) constructing a three-dimensional image of the object at the selected points based upon the peak values.