Dentition Image Capture with Multi-Angle Halation Removal
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Solution Overview
Problem
Halation (whiteout) occurs on tooth surfaces due to specular reflection from saliva, blood, or metal inlays, leading to unclear tooth images.
Innovation Solution
A dentition image capturing system using multiple illumination devices to capture images from different directions, followed by image processing to identify and remove halation regions based on similarity analysis and synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is irradiated onto a tooth surface to capture an image, then the tooth becomes visible, but halation (whiteout) occurs due to specular reflection from saliva, blood, or metal inlays, causing the image to become unclear
Solution Approach 1:
The patent segments the captured image into multiple regions based on luminance characteristics. The image processing unit divides the image into a halation region (high luminance area) and a non-halation region, allowing different processing methods to be applied to each segment. This segmentation enables targeted removal of halation effects while preserving legitimate high-luminance features like metal inlays.
Solution Approach 2:
The patent changes the luminance threshold parameter dynamically to distinguish between halation and legitimate high-luminance objects. By comparing luminance values against adjustable thresholds and analyzing the spatial distribution of high-luminance regions, the system adapts the parameter settings to differentiate specular reflection (halation) from actual reflective surfaces like metal inlays, thereby resolving the contradiction between maintaining illumination and preventing image degradation.
2Measurement precision
If multiple illumination devices are used to capture images from different directions, then halation can be identified and removed, but the device complexity increases
Solution Approach 1:
The patent employs periodic illumination sequences where multiple illumination devices activate in alternating or sequential patterns. By capturing images during different illumination phases, the system creates temporal variations that help identify halation regions. The image processing unit compares images taken under different illumination conditions to detect consistent high-luminance areas that indicate halation, thereby achieving accurate detection without requiring all illumination devices to operate simultaneously.
3Measurement precision
If image processing is performed to remove halation regions, then tooth image clarity is improved, but processing time and computational resources increase
Solution Approach 1:
The patent performs preliminary identification of halation regions using luminance thresholding and region-based analysis before executing the full image synthesis process. The image processing unit first detects high-luminance areas, determines whether they represent halation or legitimate features, and prepares replacement regions in advance. This preliminary action reduces the computational burden of the subsequent synthesis step by pre-identifying problem areas that require processing.
Solution Approach 2:
The patent applies partial processing only to regions identified as containing halation, rather than processing the entire image uniformly. The image synthesis processing unit selectively replaces only the halation regions with corresponding areas from alternative images, leaving the rest of the image unchanged. This partial action approach significantly reduces processing time and computational resources while maintaining overall image quality.
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
Clear capture of tooth images is achieved by removing halation, ensuring accurate tooth state confirmation.
Implementation Method 1
a plurality of illumination devices configured to irradiate a tooth to be captured with light from different directions
Implementation Method 2
an imaging device configured to capture first and second dentition images including the tooth under different illumination conditions
Implementation Method 3
halation (so-called 'whiteout') may occur due to specular reflection on a surface of the tooth
Data Source
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AI summary
A dentition image capturing system includes: a plurality of illumination devices configured to radiate light from different directions; an imaging device configured to capture first and second dentition images under different illumination conditions in a predetermined exposure period; a high luminance region extraction unit configured to extract a high luminance region for each of the first and second dentition images; a high luminance region comparison unit configured to calculate a degree of similarity indicating a degree of similarity between the high luminance region of the first dentition image and the high luminance region of the second dentition image; a halation region specification unit configured to specify the high luminance region of the first dentition image as a halation region in a case where the degree of similarity degree is smaller than a predetermined similarity threshold; an image synthesis processing unit configured to execute image synthesis processing of extracting a trimming region in the second dentition image corresponding to the halation region and replacing the halation region with the trimming region; and a dentition image output unit configured to output the first dentition image subjected to image synthesis processing.