Intraoral Scanning With Focus Variation for Fast Handheld 3D Mapping
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Solution Overview
Problem
Existing 3D scanning technologies are limited by the need for a controlled spatial relation between the scanner and the object, leading to slow scanning times and sub-optimal signal-to-noise ratios, particularly in handheld applications.
Innovation Solution
A scanner that varies the focus plane without moving relative to the object, using a spatial or time-varying illumination pattern to distinguish in-focus and out-of-focus regions, allowing for fast and precise 3D surface registration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If confocal microscopy principle is applied with point illumination and pinhole, then measurement precision is improved, but scanning speed deteriorates due to raster scanning requirement
Solution Approach 1:
The patent divides the illumination into multiple discrete points arranged in a pattern across the object surface. Instead of scanning point-by-point through raster movement, multiple points are illuminated simultaneously, segmenting the scanning process into parallel measurements that dramatically increase throughput while maintaining the precision benefits of confocal imaging.
Solution Approach 2:
The patent transitions from one-dimensional sequential raster scanning to two-dimensional parallel illumination by arranging multiple illumination points across the object surface. This dimensional expansion allows simultaneous measurement of multiple surface locations, converting a slow sequential process into a fast parallel process without sacrificing measurement precision.
2Ease of operation
If handheld scanner is used without controlled spatial relation, then ease of operation is improved, but measurement precision deteriorates due to inability to maintain fixed spatial relation
Solution Approach 1:
The patent employs dynamic focus plane variation where the focus plane is rapidly switched between multiple predetermined positions during the scanning process. This dynamic adjustment allows the system to accommodate the handheld scanner's variable spatial relationship with the object while maintaining precise focus plane determination through controlled variation in focus positions.
Solution Approach 2:
The patent changes the focus plane parameter to multiple predetermined positions during scanning. By systematically varying the focus plane parameter across different positions and combining this with the spatial pattern of illumination points, the system maintains measurement precision even when the scanner's spatial relation to the object is not controlled, as the focus plane variations compensate for positional variations.
3Productivity
If multiple illumination points are used simultaneously, then scanning speed is improved, but signal-to-noise ratio deteriorates due to reduced light intensity at each point
Solution Approach 1:
The patent employs periodic illumination patterns where multiple illumination points are activated in a systematic sequence. The periodic variation in illumination allows the system to maintain adequate light intensity at each point during its active phase while still achieving fast scanning through the periodic activation of multiple points. This temporal modulation ensures sufficient signal strength for each measurement point.
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
Enables fast, precise, and efficient 3D scanning with improved signal-to-noise ratio, suitable for handheld use and capable of scanning both external and internal surfaces with reduced data processing time.
Implementation Method 1
transmitting at least a part of the light returned from the object to the camera
Implementation Method 2
varying the position of the focus plane of the pattern on the object
Data Source
AI summary
A scanner includes a camera, a light source for generating a probe light incorporating a spatial pattern, an optical system for transmitting the probe light towards the object and for transmitting at least a part of the light returned from the object to the camera, a focus element within the optical system for varying a position of a focus plane of the spatial pattern on the object, unit for obtaining at least one image from said array of sensor elements, unit for evaluating a correlation measure at each focus plane position between at least one image pixel and a weight function, a processor for determining the in-focus position(s) of each of a plurality of image pixels for a range of focus plane positions, or each of a plurality of groups of image pixels for a range of focus plane positions, and transforming in-focus data into 3D real world coordinates.