3D Polyhedral Marker Imaging for Single-Camera Anatomical Mapping
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Solution Overview
Problem
Existing methods for obtaining spatial patterns of anatomical structures, such as stereophotogrammetry, require a high number of markers and cameras, leading to complex image calibration and inefficient processing, and expose subjects to harmful ionizing radiation.
Innovation Solution
A method using calibrated images captured by a single digital device with a minimal number of markers, each having a three-dimensional polyhedral shape, allowing for accurate determination of contact points with body landmarks through geometric relationships and image recognition, without ionizing radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stereophotogrammetry uses a high number of markers and cameras, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent transitions from traditional 2D planar markers to 3D polyhedral markers with multiple exposed faces. This dimensional change allows a single marker to provide multiple geometric reference points (vertices and face centers) that can be detected from different angles, effectively replacing multiple 2D markers while maintaining or improving measurement precision through enhanced spatial information.
Solution Approach 2:
The polyhedral marker serves multiple functions simultaneously: it provides geometric reference for 3D localization, offers multiple detectable features (vertices and face centers) for angle determination, and enables identification of the normal vector to the body surface. This multi-functionality reduces the overall number of components needed in the measurement system.
2Measurement precision
If multiple cameras are used for stereophotogrammetry, then measurement precision is improved, but processing complexity increases
Solution Approach 1:
The 3D polyhedral marker provides rich geometric information including vertices, face centers, and edge orientations that can be detected from a single image. This dimensional enrichment allows accurate 3D reconstruction and angle determination without requiring complex multi-camera calibration, as the marker's three-dimensional geometry inherently encodes spatial relationships.
3Measurement precision
If radiographic imaging is used for morphological analysis, then measurement precision is improved, but harmful radiation exposure increases
Solution Approach 1:
The patent replaces ionizing radiation-based radiographic imaging with optical imaging using visible light and digital cameras. The polyhedral markers with reflective or brightly colored surfaces provide sufficient contrast and geometric information for accurate 3D reconstruction and biometric analysis without any harmful radiation exposure to the subject.
Data Source
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AI summary
A method is disclosed for obtaining a spatial pattern of an anatomical structure of a subject (H), comprising the steps of a) acquiring from a digital image capturing device (112) an uncalibrated image of a calibration reference applied on a surface (118) configured to receive the subject (H), the calibration reference having at least one known dimension and defining at least one known direction; b) defining an absolute calibrated reference system of coordinates (x, y, z) based on the calibration reference depicted in the uncalibrated image; c) acquiring, from said digital image capturing device (112), first and second calibrated images of a plurality (110) of markers applied on a corresponding plurality of body landmarks of the anatomical structure of the subject (H) at respective contact points with the body landmarks, and arranged within the absolute calibrated reference system (x, y, z); wherein the first calibrated image depicts a marker spatial arrangement in a first plane (x, z) and the second calibrated image depicts the marker spatial arrangement in a second plane (y, z) different from the first plane (x, z), the first and second planes (x, z; y, z) being representative of a relative orientation of the plurality (110) of markers with respect to the at least one digital image capturing device (112); wherein the markers of the plurality (110) of markers each comprise a respective three- dimensional main body (12) shaped as a polyhedron of N faces and having N-1 exposed faces arranged in a known geometric relationship with the contact point of the marker with the respective body landmark; and wherein at least one of the N-1 exposed faces of each marker is identifiable in the first and second calibrated images by means of an image recognition algorithm.