Three-dimensional measurement of an inner surface profile using a supercontinuum beam

Area of Science:

• Optical Metrology
• Surface Profilometry
• Materials Science

Background:

• Speckle effects in optical measurements degrade spatial resolution and data accuracy.
• Conventional lasers like He-Ne lasers are limited by speckle noise.
• Accurate inner surface profile measurement is crucial for component wear analysis.

Purpose of the Study:

• To demonstrate an improved inner surface profile measurement technique using a supercontinuum beam.
• To quantify the reduction in speckle contrast and point cloud deviation.
• To evaluate the radial spatial resolution achievable with this new method.

Main Methods:

• Utilizing a supercontinuum beam for inner surface profile measurement.
• Employing a compact probe for analyzing wear in an automobile component's small hole.
• Comparing results against a conventional green He-Ne laser (543.5 nm).

Main Results:

• Supercontinuum beam suppressed speckle contrast to 22% and standard deviation to 40%.
• Achieved a radial spatial resolution of 2 μm, comparable to the supercontinuum beam's wavelength.
• Demonstrated a fivefold improvement in radial spatial resolution over monochromatic beams.

Conclusions:

• Supercontinuum light effectively reduces speckle, enabling high-resolution surface profiling.
• The developed method is suitable for precise measurement of wear depth in automotive components.
• This technique offers significant advancements in optical metrology for surface analysis.