Structured Light Illumination for Extended Depth of Field
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Solution Overview
Problem
Existing mouth scanners face a challenge in maintaining system brightness while increasing the depth of field (DOF) without reducing the lens aperture, which affects image resolution.
Innovation Solution
An illuminating device that generates two light beams with different optical properties and uses light gates at different positions to produce images with two distinct depths of field, allowing simultaneous imaging without compromising aperture size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the lens aperture size is reduced to increase the depth of field, then the depth of field is improved, but the light intensity and resolution deteriorate
Solution Approach 1:
The patent divides the illumination function into multiple light sources with different wavelengths (first light source emitting first wavelength, second light source emitting second wavelength). Each light source illuminates the object from different angles and creates images with different depths of field, allowing the system to capture both near and far regions simultaneously without compromising brightness or resolution
Solution Approach 2:
The patent changes the wavelength parameter of light by using multiple light sources with different wavelengths. This allows different penetration depths and focusing characteristics, enabling the system to achieve extended depth of field while maintaining adequate light intensity for each wavelength band
2Manufacturing precision
If the lens aperture size is reduced to increase the depth of field, then the depth of field is improved, but the resolution deteriorates
Solution Approach 1:
The patent segments the imaging process by using multiple light sources with different wavelengths that create images with different depths of field. The imaging device captures multiple images simultaneously, and the processor combines them to produce a final image with high resolution across the entire depth range, avoiding the resolution loss that would occur with a single small aperture
Solution Approach 2:
The patent introduces the wavelength dimension as an additional degree of freedom. By utilizing light sources with different wavelengths, the system can control the depth of field independently for each wavelength, thereby achieving high resolution across multiple depth planes simultaneously rather than being constrained by a single aperture setting
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
The solution maintains brightness and increases the depth of field without reducing the aperture, resulting in improved image resolution and accuracy in capturing detailed images of objects with varying depths.
Implementation Method 1
The light-emitting device is configured to generate a first light beam L1 having a first wavelength to illuminate an object S to be measured
Implementation Method 2
The light gate device includes a first light gate 122 and a second light gate 124. The first light beam L1 passes through the light gate device 120 and produces a first image within a first depth of field range D1
Data Source
AI summary
An illuminating device includes a projection device and an imaging device recording a first image and a second image. The projection device includes a light-emitting device generating a first light beam and a second light beam different from the first light beam to illuminate an object to be measured and a light gate device located in optical paths of the first and light beams and including a first light gate and a second light gate respectively located on a light incident surface and a light exit surface of the light gate device. The first and second light beams pass through the light gate device and respectively produces the first image in a first depth of field range and the second image in a second depth of field range different from the first depth of field range. The first and second image are projected on the object to be measured.