Apparatus and method for determining borehole size with a borehole imaging tool

A logging tool, comprising:

• a tool string having a longitudinal axis;
• a plurality of springs comprising first and second pairs of springs coupled to the tool string, wherein the springs of the first pair are disposed opposite one another about the longitudinal axis, a first end of each spring of the plurality of springs is rigidly fixed to the tool string to block both axial motion of the first end along the longitudinal axis and rotational motion of the first end about the longitudinal axis, the first end of each spring of the first pair of springs is disposed at a first axial position along the tool string, the first end of each spring of the second pair of springs is disposed at a second axial position along the tool string, and the first and second axial positions are different from one another;
• a plurality of sensors, wherein one sensor of the plurality of sensors is disposed on one spring of the first pair of springs, and another sensor of the plurality of sensors is disposed on one spring of the second pair of springs;
• a first hub connected to a second end of each spring of the first pair of springs, wherein the first hub is disposed about and moveably coupled to the tool string, and wherein the first hub comprises a first magnet having a first magnetic field;
• and
• an array of magnetoresistive sensors disposed in the tool string such that the first hub is configured to move along the longitudinal axis of the tool string about the array of magnetoresistive sensors.