Depth Sensor Toe Tip Position Calculation for Foot Clearance
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Solution Overview
Problem
Current methods for measuring foot clearance using depth sensors are hindered by the difficulty in accurately determining the position of the toe tip, making it challenging to measure foot clearance effectively and inexpensively.
Innovation Solution
A measurement device and method that utilize a depth sensor to capture images of a walking path, acquire and compare reference and walking data to identify the leg and extract toe tip pixels based on depth, calculating three-dimensional coordinates to determine the toe tip position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If markers are attached to 13 locations on the subject and six cameras are used to capture images, then measurement precision of foot clearance is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and focuses only on the essential element needed for foot clearance measurement - the toe tip position - rather than using comprehensive multi-camera systems with multiple markers. By isolating the critical measurement point and using depth sensor technology, the system achieves necessary measurement precision with significantly reduced device complexity
Solution Approach 2:
The patent replaces the mechanical/optical system of multiple physical cameras and markers with a depth sensor-based system that uses depth information and image processing algorithms. This substitution eliminates the need for complex mechanical positioning of multiple cameras while maintaining measurement capability through computational methods
2Measurement precision
If six cameras and 13 markers are used for measurement, then measurement precision is improved, but ease of operation deteriorates due to heavy burden on measurer and subject
Solution Approach 1:
The patent enables the measurement system to automatically identify and track the toe tip position through depth sensor data and image processing, eliminating the need for manual marker placement and camera positioning. The system performs self-calibration and automatic measurement, significantly reducing the operational burden on both the measurer and the subject
3Device complexity
If depth sensor is used to capture images, then device complexity and cost are reduced, but measurement precision deteriorates due to inability to identify toe tip position
Solution Approach 1:
The patent leverages the depth dimension provided by depth sensors to accurately identify the toe tip position in three-dimensional space. By utilizing depth information rather than relying solely on two-dimensional image data, the system achieves precise toe tip localization despite using a single sensor, thereby maintaining measurement precision while reducing device complexity
Solution Approach 2:
The patent changes the measurement parameters from marker-based positional tracking to depth-based spatial analysis. By processing depth values and pixel coordinate information through specific algorithms, the system extracts accurate toe tip position data, transforming the way measurement parameters are utilized to overcome the limitations of depth sensor technology
Data Source
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AI summary
To measure the position of a toe tip of a walking user, a measurement device 10 includes: a data acquisition unit 11 that acquires, from a depth sensor disposed so as to capture an image of a walking path and a space thereabove and outputting image data having a depth of each pixel added thereto, image data for a state in which there is no user on the walking path as reference data and image data for a state in which a user is walking on the walking path as walking data; a specific pixel extraction unit 12 that identifies a depth-sensor side foot from a difference between the walking data and the reference data and extracts, on the basis of the depth, a pixel corresponding to a toe-tip part among the pixels of the specified foot; and a position calculation unit 13 that calculates three-dimensional coordinates of the extracted pixel on the basis of the coordinates in the image data and the depth of the pixel, and takes the three-dimensional coordinates as the position of the toe tip of the user.