Laparoscopic Camera Alignment Correction Using Optical Markers
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Solution Overview
Problem
Laparoscopic cameras experience image dislocations due to external forces acting on the elongated shaft, leading to inaccuracies in surgical operations.
Innovation Solution
An endoscopic camera arrangement with optical markers placed within the optical path, allowing for detection and correction of deformations and misplacements of the objective relative to the image converter, using a mathematical projection model to adjust the position data and correct image distortions without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the elongated shaft is flexible to be introduced into the body, then ease of operation is improved, but image stability deteriorates due to external forces causing image dislocations
Solution Approach 1:
The patent implements feedback by continuously monitoring the position of the objective relative to the image converter using optical markers and image processing. The system detects displacements caused by flexible shaft deformation and automatically compensates for them through mathematical correction, maintaining image stability despite the flexible shaft's movement
Solution Approach 2:
The patent replaces mechanical rigid coupling with an optical-mathematical system. Instead of using a rigid shaft to maintain objective-image converter alignment, the system uses optical markers captured by the image converter and mathematical projection models to detect and correct alignment deviations, substituting mechanical constraints with computational correction
2Measurement precision
If optical markers are added to correct image dislocations, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses optical markers that create simplified copies or representations of position information. The markers are imaged by the image converter to produce 2D image signals that encode 3D position data, allowing precise position measurement through image processing without requiring complex physical sensors or additional measurement devices
Solution Approach 2:
The image converter serves multiple functions: it captures the surgical scene through the objective and simultaneously captures images of the optical markers for position detection. This multi-functionality allows the system to achieve precise position measurement without adding separate dedicated sensors, thereby limiting the increase in device complexity
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
Ensures precise image registration by correcting mechanical inaccuracies and deformations, enhancing the accuracy of surgical operations by aligning the physical world space with the camera image space.
Implementation Method 1
an objective (33) optically coupled to the image converter (31)
Implementation Method 2
The objective (33) forms an optical image of the object (36) on the image converter (31)
Implementation Method 3
at least one optical marker (39-42) is placed within the optical path of the objective (33) for being projected onto the image converter (31)
Data Source
AI summary
Augmented reality applications require precise camera calibration to reduce the overall target registration errors. The camera calibration determines the mathematical model of the camera in order to determine how the physical world space is mapped to the camera image space and thus is highly dependent on the optics of the camera. The camera calibration algorithm normally assumes that the optics of the camera is rigidly fixed, which in fact is not at least for tilted laparoscopic cameras as illustrated in FIGS. 6 to 8. Furthermore, any mechanical play between elements of the objective and the image converter will render the optics variable. According to the invention markers to will be placed within the field of view of the laparoscopic camera, which allows for determination of rotation of the optical part and mechanical misalignment without the necessity or providing any additional sensor.