Dental 3D Camera Using Adjustable Focus and Color Filters
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Solution Overview
Problem
Existing methods for three-dimensional measurement of dental objects are prone to positioning errors due to mechanically driven projection gratings and lack the capability for color measurement.
Innovation Solution
A camera system with adjustable focusing optics and color filters in both projection and observation masks, allowing incremental focal distance adjustment and enabling both three-dimensional and color measurement without mechanically movable components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanically driven projection gratings are used to generate temporally changing projection patterns, then three-dimensional measurement can be achieved, but positioning errors occur due to incorrect control or actuation
Solution Approach 1:
The patent replaces mechanically driven projection gratings with a digital light projector that uses liquid-crystal elements (LCD) to generate projection patterns. This substitution eliminates mechanical moving parts and their associated positioning errors, achieving error-free three-dimensional measurement through electronic control of the projection pattern generation.
Solution Approach 2:
The patent changes the state of the projection pattern from mechanically generated temporal changes to digitally controlled optical changes. By using a liquid-crystal-based digital light projector, the system can dynamically alter projection patterns through electrical control of liquid crystal elements, eliminating mechanical actuation errors while maintaining the ability to generate temporally changing patterns for 3D measurement.
2Measurement precision
If conventional three-dimensional measurement methods are used, then depth information can be obtained, but color measurement capability is lost
Solution Approach 1:
The patent implements a multi-functional measurement system that simultaneously performs both three-dimensional measurement and color measurement. The digital light projector with liquid-crystal elements can generate different projection patterns while the sensor captures both depth information (through focus variation) and color information (through spectral detection), enabling the system to acquire multiple types of measurement data in a single integrated setup.
Solution Approach 2:
The patent extends the measurement capability from purely spatial (three-dimensional) to include spectral dimensions (color). By incorporating color filters and spectral detection in the sensor system, the patent adds a spectral dimension to the traditional 3D measurement, enabling simultaneous acquisition of both geometric and colorimetric properties of the dental object.
3Volume of moving object
If a compact camera design is implemented, then integration into handpiece housing is achieved, but space for mechanical components is reduced
Solution Approach 1:
The patent replaces mechanical projection gratings and moving components with a compact digital light projector using liquid-crystal elements. This substitution dramatically reduces the space required for mechanical components, enabling integration into a compact handpiece housing while maintaining or enhancing measurement capabilities through electronic control systems.
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 camera system provides accurate, error-free three-dimensional data and color measurement by optimizing focal positioning and utilizing color filters to enhance image clarity and spectral separation.
Implementation Method 1
The light source can be a white LED, or a group of colored LEDs, for example, that emits an illumination beam with a broad spectrum
Implementation Method 2
The projection mask consists of a plurality of projection pattern elements containing a variety of color filters. The observation mask likewise consists of a plurality of observation mask elements containing a variety of color filters
Implementation Method 3
focusing optics that display the projection pattern in a plane of sharp focus at a defined focal distance relative to the dental camera
Implementation Method 4
the projection pattern projected onto the object is reflected by the object as an observation beam and is acquired by means of a sensor
Data Source
AI summary
The invention relates to a method and a camera for the three-dimensional measurement of a dental object, comprising at least one light source that emits an illumination beam, at least one projection mask that produces a projection pattern, focusing optics that display the projection pattern in a plane of sharp focus at a defined focal distance relative to the dental camera. The projection pattern projected onto the object is reflected by the object as an observation beam and is acquired by means of a sensor. During the measurement of the object, the focusing optics are controlled in such a way that the focal distance of the plane of sharp focus relative to the camera is adjusted incrementally between a number of defined scan positions.