Phase shifting imaging module and method of imaging

An imaging system comprising:

• at least one radiation source configured to illuminate a part surface to be tested;
• at least one lens configured to collimate a radiation beam;
• at least one polarizer configured to polarize the radiation beam;
• and
• a phase shifting imaging module configured to split the radiation beam into four aligned radiation beams, and to then phase shift the four aligned radiation beams, the phase shifting imaging module comprising:
• a first beam splitter configured to split an image radiation beam into first and second image radiation beams;
• a first prism configured to align the first and second image radiation beams;
• a second beam splitter configured to split the first and second image radiation beams into four image radiation beams;
• a second prism configured to align the four image radiation beams;
• and
• a phase mask that receives the four image radiation beams and is configured to introduce a phase retardation between the four image radiation beams resulting in four phase shifted image radiation beams.

A method for measuring a surface feature of a part with a coherent image radiation source, comprising:

• irradiating a surface with a coherent electromagnetic radiation beam;
• receiving an image radiation beam from the surface;
• splitting the image radiation beam into first and second image radiation beams;
• aligning the first and second image radiation beams;
• splitting the first and the second image radiation beams into four radiation beams;
• aligning the four radiation beams;
• phase shifting the four radiation beams after alignment;
• and
• generating image data via a pixilated sensor.