Eccentric Camera Surveying Instrument for Stereo Photogrammetry
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Solution Overview
Problem
Current surveying instruments face challenges in accurately determining coordinates of targets using photogrammetry, particularly in close-range applications, due to the need for multiple camera positions and potential errors from external variables like lighting conditions.
Innovation Solution
A method and system utilizing a surveying instrument with a camera positioned eccentric to its rotation center, capturing two images while rotating around horizontal and vertical axes, and using GNSS signals to determine target coordinates, reducing the need for a baseline measurement and minimizing viewpoint changes between images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple camera positions are used for stereophotogrammetry, then measurement accuracy is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent combines the camera with the surveying instrument into a single integrated system. The camera is mounted on the surveying instrument such that it shares the same rotation axes (horizontal and vertical) and rotates synchronously with the instrument. This merging eliminates the need for separate camera positioning equipment and simplifies the overall device structure while maintaining the capability to capture images from multiple positions through instrument rotation.
Solution Approach 2:
The surveying instrument serves multiple functions: it performs traditional surveying measurements and simultaneously functions as a stereophotogrammetry system. The camera integrated with the instrument can capture images at different angles by rotating with the instrument, eliminating the need for dedicated photogrammetry equipment. This multi-functionality reduces device complexity while achieving accurate coordinate determination.
2Measurement precision
If multiple camera positions are used for stereophotogrammetry, then measurement accuracy is improved, but time consumption increases
Solution Approach 1:
The camera rotates continuously with the surveying instrument during the measurement process. Instead of positioning the camera at discrete locations and setting up separately at each position, the integrated system captures images continuously as the instrument rotates to different angles. This continuous action significantly reduces the time required to acquire images from multiple positions while maintaining measurement accuracy.
Solution Approach 2:
The system transitions from static camera positioning to dynamic image capture. The camera is dynamically positioned by rotating the entire surveying instrument assembly, allowing images to be captured from multiple angles in succession. This dynamic approach eliminates the time-consuming process of manually repositioning camera equipment between shots.
3Device complexity
If camera is positioned at rotation center, then device simplicity is maintained, but stereophotogrammetry capability is limited
Solution Approach 1:
The camera is deliberately positioned asymmetrically relative to the rotation center, specifically offset along the vertical axis. This asymmetric positioning creates the necessary baseline for stereophotogrammetry while maintaining a simple integrated structure. The vertical offset allows the camera to capture images at different vertical angles when the instrument rotates, providing the parallax needed for three-dimensional coordinate determination without complicating the device layout.
4Adaptability or versatility
If instrument is moved between image captures, then different viewpoints are achieved, but measurement errors from external variables increase
Solution Approach 1:
The camera and surveying instrument are merged into a single rigid assembly that rotates together as one unit. This ensures that the relative position between the camera and the instrument's rotation center remains constant during rotation. By combining the positioning function (surveying instrument) with the imaging function (camera) into a single synchronized system, the patent eliminates errors that would arise from independent positioning and ensures consistent measurement references across all captured images.
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
This approach provides highly accurate, cost-effective, and time-efficient coordinate determination for close-range targets, reducing occlusion issues and external variable errors, while using a single camera setup, thus simplifying the image capture process and eliminating the need for moving the instrument.
Implementation Method 1
rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position and orientation
Implementation Method 2
determining coordinates of the surveying instrument using signals from one or more Global Navigation Satellite System (GNSS) signals
Implementation Method 3
capturing a first image using the camera in the first camera position and orientation
Data Source
AI summary
A method for determining, in relation to a surveying instrument, target coordinates of a point of interest, or target, identified in two images captured by a camera in the surveying instrument. The method comprises determining coordinates of the surveying instrument, capturing a first image using the camera in the first camera position; identifying, in the first image, an object point associated with the target; measuring first image coordinates of the object point in the first image; rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position; capturing a second image using the camera in the second camera position; identifying, in the second image, the object point identified in the first image; measuring second image coordinates of the object point in the second image; and determining the coordinates of the target in relation to the surveying instrument.