3D Shape Measurement Using Prism Phase Modulation
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Solution Overview
Problem
Conventional three-dimensional shape measuring apparatuses require a z-axis scan in addition to x and y-axis scans to measure the height of a measurement target object, which is inefficient and increases mechanical movement distance.
Innovation Solution
A three-dimensional shape measuring apparatus using a prism unit that changes the phase of reflective light according to the height of the measurement target object, allowing the imaging unit to capture images with varying diameters, enabling height measurement without z-axis movement by analyzing image diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional three-dimensional shape measuring apparatus uses an imaging unit that moves along the z-axis to measure height differences, then the height measurement can be performed, but the measurement time and mechanical movement distance increase
Solution Approach 1:
The patent replaces the mechanical z-axis movement system with an optical phase modulation system using a prism. Instead of physically moving the imaging unit to capture images at different heights, the prism modulates the phase of reflected light according to object height, encoding height information in the optical phase. This substitution eliminates the need for mechanical z-axis scanning while preserving height measurement capability.
Solution Approach 2:
The patent changes the measurement parameter from physical position (z-axis coordinate) to optical phase. The prism unit converts height variations into phase variations of reflected light. By measuring phase changes rather than physical displacements, the system achieves height measurement without mechanical movement, thereby reducing measurement time and eliminating the need for z-axis scanning mechanisms.
2Measurement precision
If a conventional three-dimensional shape measuring apparatus performs x, y, and z-axis scans to measure three-dimensional shape, then complete three-dimensional information is obtained, but the device complexity and mechanical movement requirements increase
Solution Approach 1:
The patent eliminates the mechanical z-axis scanning system by substituting it with an optical phase modulation approach. The prism unit encodes height information into the phase of reflected light, allowing the imaging unit to remain stationary in the z-direction while still capturing three-dimensional shape information. This reduces device complexity by removing the need for z-axis scanning mechanisms.
Solution Approach 2:
The patent introduces a prism unit as an intermediary between the illumination source and the imaging unit. This prism acts as a mediator that converts height information into optical phase information, enabling the imaging unit to capture three-dimensional shape data without requiring physical movement along the z-axis. The intermediary transforms the measurement problem from a mechanical scanning task to an optical phase analysis task.
3Reliability
If the imaging unit moves along the z-axis to focus on objects at different heights, then accurate images are captured, but the mechanical movement distance and time consumption increase
Solution Approach 1:
The patent replaces the mechanical focus adjustment mechanism with an optical phase encoding system. Instead of moving the imaging unit to achieve focus at different heights, the prism modulates the phase of light based on object height, allowing the imaging unit to capture focused images of objects at different heights simultaneously without mechanical movement. This maintains image focus accuracy while eliminating focus adjustment time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the time and mechanical movement required for acquiring a three-dimensional shape by allowing a two-dimensional plane scan, enhancing driving efficiency and simplifying the measurement process.
Implementation Method 1
a prism unit configured to receive reflective light reflected from the measurement target object and direct the reflective light to an image formation lens
Data Source
AI summary
The present disclosure relates to a three-dimensional shape measurement apparatus for obtaining height information of a measurement target object using a prism. The three-dimensional shape measurement apparatus includes an illumination unit irradiating light on the measurement target object, a prism unit receiving reflective light reflected from the measurement target object and directing the reflective light to an image formation lens, an imaging unit receiving the reflective light from the prism unit and capturing an image of the reflective light, and a height measurement unit measuring a height of the measurement target object based on the image captured by the imaging unit.