Microscopic Three-Dimensional Measurement Based on Telecentric Stereo and Speckle Projection Methods

Area of Science:

• Metrology
• Optical Measurement
• Microscopy

Background:

• Accurate three-dimensional (3D) measurement of microstructures is crucial in various scientific and industrial fields.
• Existing microscopic measurement methods often lack the required accuracy (sub-pixel or sub-micron) for millimeter-scale dimensions.

Purpose of the Study:

• To develop and validate a novel method for high-accuracy 3D measurement of microstructures at the millimeter scale.
• To address the limitations of current techniques in achieving sub-micron precision for macroscopic microstructures.

Main Methods:

• A microscopy experimental setup was designed using two telecentric cameras and an industrial projection module.
• A telecentric binocular stereo reconstruction procedure was implemented.
• The method combines microscopic stereo measurement with digital speckle projection.

Main Results:

• Measurement accuracy was verified using grid arrays and cylinder arrays with varying height differences.
• Further verification was performed using two Mitutoyo step masters.
• The proposed method successfully obtained 3D microstructure information with sub-pixel and sub-micron accuracy in the millimeter scale.

Conclusions:

• The developed method effectively achieves high-accuracy 3D measurement of microstructures at the millimeter scale.
• This technique overcomes previous limitations, offering a viable solution for precise dimensional analysis of micro-objects.