Camera-Guided Head Positioning for Reproducible Cephalometric Imaging
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Solution Overview
Problem
Existing cephalometric radiography methods rely on ear rods for head positioning, which are prone to errors due to variations in ear canal size and morphology, leading to inconsistent head orientation and reduced precision in morphological diagnosis of the maxillofacial region.
Innovation Solution
A head positioning method using two digital cameras with orthogonal optical axes to establish horizontal and vertical reference lines, allowing precise adjustment of the head's position and orientation, including lateral and frontal positioning steps to standardize the head's position relative to the external auditory canals and eye centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ear rods are used for head positioning, then the positioning process is simple and quick, but the precision and reproducibility of head positioning deteriorate due to variations in ear canal size and morphology
Solution Approach 1:
The patent introduces optical cameras and reference lines as intermediary tools between the positioning apparatus and the patient's head. The cameras capture images through the ear rods, and reference lines are superimposed to provide visual feedback for precise positioning, thereby maintaining operational simplicity while significantly improving positioning precision
Solution Approach 2:
The patent replaces the purely mechanical ear rod positioning system with an optical measurement and feedback system. Digital cameras, image processing, and visual reference lines substitute for mechanical adjustment mechanisms, enabling non-contact, high-precision positioning that accounts for individual anatomical variations
2Device complexity
If ear rods are used for head positioning, then the device structure remains simple, but the reproducibility of head orientation deteriorates due to rotational displacement
Solution Approach 1:
The patent implements a feedback mechanism where optical cameras capture real-time images of the patient's head through the ear rods, reference lines are superimposed on the images, and the positioning is adjusted based on visual feedback until the reference lines align with anatomical landmarks. This closed-loop feedback system ensures consistent and reproducible head orientation across multiple measurements
Solution Approach 2:
The patent creates a universal positioning system that works for all patients regardless of individual anatomical variations. The optical measurement system and reference line methodology can be applied to any patient, ensuring standardized and reproducible positioning across different individuals and measurement sessions
3Productivity
If conventional cephalometric radiography is performed, then the diagnostic process is efficient, but the accuracy of morphologic evaluation deteriorates due to positioning errors
Solution Approach 1:
The patent performs preliminary positioning verification using optical cameras and reference lines before the actual cephalometric radiography is taken. This preliminary action ensures that the head is correctly positioned and oriented, preventing positioning errors from affecting the subsequent diagnostic imaging while maintaining overall process efficiency
Data Source
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AI summary
Limited precision of head standardization is a problem in the prior art. In the present invention, positioning of a patient head is standardized using two cameras, namely, a first digital camera 11 and a second digital camera 12. In a profile positioning step, while a display on a first monitor 13 is viewed, the vertical position of the first digital camera 11 is adjusted, and instructions are given to the patient to adjust the forward-backward position of the head so that the point of intersection of a first vertical reference line VL1 and a first horizontal reference line HL1 corresponding to the camera optical axis of the first digital camera 11 is in the center of the ear canal of the patient. In a front positioning step, while a display on a second monitor 16 is viewed, the vertical position of the second digital camera 12 is adjusted so that a second horizontal reference line HL2 passes through the center of the left and right eyeballs of the patient, and instructions are given to the patient to adjust the left-right inclination of the head and face such that the heights of the left and right eyes are equal, and to adjust the left-right orientation of the head and face so that a second vertical reference line VL2 passes through the center of the left and right eyes of the patient.