Displacement measurements using phase changes

A measurement system comprising:

• an image capture device configured to capture images of an object;
• and
• a processing system coupled to receive image data from the image capture device, wherein the processing system implements a measurement process that functions to:
• transform data corresponding to a first image and a second image of an object into frequency domain data;
• determine phases corresponding to the frequency domain data;
• identify at least one frequency of the phases having a known property;
• assign weights to the phases dependent on the identified at least one frequency;
• and
• use the phases and the weights to determine a slope corresponding to change in phase with change in frequency, wherein the slope indicates a displacement of the object.

A system for measuring a displacement, comprising:

• means for capturing a first image of an object before the displacement and a second image of the object after the displacement;
• means for transforming data corresponding to the first image and the second image into frequency domain data;
• means for determining phases corresponding to the frequency domain data;
• means for identifying at least one frequency of the phases having a known property;
• means for assigning weights to the phases dependent on the identified at least one frequency;
• and
• means for using the phases and the weights to determine a slope corresponding to change in phase with change in frequency, wherein the slope indicates the displacement.

A computer-readable storage medium containing a set of instructions comprising:

• a routine for transforming data corresponding to a first image of an object and a second image of the object into frequency domain data;
• a routine for determining phases corresponding to the frequency domain data;
• a routine for identifying at least one frequency of the phases having a known property;
• a routine for assigning weights to the phases dependent on the identified at least one frequency;
• and
• a routine for using the phases and the weights to determine a slope corresponding to change in phase with change in frequency, wherein the slope indicates a displacement of the object.