Camera Calibration Using a Tracking Camera Across Non-Overlapping Views
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Solution Overview
Problem
Conventional calibration methods for multiple cameras with non-overlapping fields of view, especially in static image sensor setups, fail to accurately determine spatial relationships, hindering effective tracking and analysis of events across different camera views.
Innovation Solution
A surgical system that includes a first and second camera, along with a tracking camera, capable of determining the relative spatial transformation between the first and second cameras by capturing images with and without overlapping fields of view, using a tracking device or marker to establish poses and positions within a common coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods are used for cameras with non-overlapping fields of view, then the calibration process is simple, but the measurement precision of spatial relationships deteriorates
Solution Approach 1:
A tracking camera serves as an intermediary device that captures images of a calibration object visible to both the first and second cameras. This mediator enables the establishment of spatial relationships between cameras with non-overlapping fields of view by providing a common reference frame, thereby resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The calibration system transitions from 2D image plane correspondence to 3D spatial coordinate transformation by using the tracking camera to capture the calibration object's position in three-dimensional space. This dimensional change enables accurate spatial relationship determination even when camera fields of view do not overlap in the 2D image plane.
2Area of stationary object
If cameras are positioned to maximize observable range, then the coverage area increases, but the overlapping field of view decreases
Solution Approach 1:
The tracking camera acts as a mediator that bridges the gap between cameras positioned to maximize coverage. By capturing images of the calibration object that is visible to both target cameras, it enables spatial calibration even when the target cameras have minimal or no overlapping fields of view, thus maintaining measurement precision while maximizing observable range.
3Measurement precision
If a tracking camera is added to the calibration system, then the measurement precision of spatial relationships improves, but the device complexity increases
Solution Approach 1:
The tracking camera serves multiple functions: it captures images of the calibration object for spatial relationship determination, provides a common reference frame for multiple target cameras, and enables calibration of cameras with non-overlapping fields of view. This multi-functionality justifies the addition of the tracking camera by maximizing its utility across different calibration scenarios.
Data Source
AI summary
A method performed by a surgical system that includes cameras within an operating room. The system receives a first image from a first camera, representing a first FOV that has an object at a first location. The system receives a second image from a tracking camera having the object at the first location, and determines a first pose of the first camera based on the first and second images. The system receives a third image captured by a second camera, representing a second, different FOV, and having the object at a second location. The system receives a fourth image captured by the tracking camera having the object at the second location, and determines a second pose of the second camera based on the third and fourth images. The system determines a relative spatial transformation between the first and second cameras based on the first and second poses.