Remote PPG Motion Compensation via Landmark Deformation
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Solution Overview
Problem
Motion compensation in remote PPG imaging is challenging, especially when imaging internal body areas with high motility, such as organs during endoscopic procedures, due to deformation and perspective changes.
Innovation Solution
A PPG imaging system that uses a processor to receive images, identify landmarks, pair and deform images to match landmarks between frames, providing motion compensation, and derive remote PPG signals from motion-compensated images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If motion stabilization is applied to compensate for camera movement, then image stability is improved, but the system cannot handle organ deformation and perspective changes in endoscopic imaging
Solution Approach 1:
The system dynamically adapts the motion compensation model based on the type of motion detected. For rigid camera movements, traditional stabilization is applied, while for organ deformations, the system switches to a deformation-aware compensation mode that preserves tissue deformation characteristics while removing camera-induced motion artifacts.
Solution Approach 2:
The system changes the compensation parameters dynamically based on the imaging context. When organ deformation is detected, the deformation magnitude and pattern parameters are adjusted to match the physiological movement patterns, allowing accurate separation of camera motion from tissue deformation.
2Ease of operation
If traditional motion stabilization is used, then camera movement is compensated, but reliable PPG signal extraction becomes difficult due to perspective changes
Solution Approach 1:
The system segments the motion compensation task into two distinct components: camera motion compensation and tissue deformation preservation. By separating these functions, the system can apply appropriate compensation to each, ensuring that PPG signal extraction is not degraded by perspective changes while still maintaining image stability.
3Ease of operation
If the camera is held by an operator or mounted on unstable support, then portability is improved, but image stability deteriorates due to operator movement
Solution Approach 1:
The system performs self-stabilization by automatically detecting and compensating for camera motion through image analysis. The motion compensation algorithm runs autonomously on the captured video stream, eliminating the need for external stabilization equipment while maintaining image quality suitable for PPG signal extraction.
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
The system effectively stabilizes images and extracts reliable PPG signals and perfusion maps, even in highly dynamic environments, allowing for accurate tissue perfusion assessment.
Implementation Method 1
deform said second image of the pair to match the landmarks in that second image of the pair with the landmarks in the first image of the pair thereby providing motion compensation
Implementation Method 2
PPG imaging utilizes an off-the-shelf camera and a light source to remotely detect the dynamic changes in blood volume beneath the skin
Data Source
AI summary
A PPG imaging system and method processes images to derive remote PPG signals. Images of a region of interest are received, and landmarks are identified in each of a set of the images. For pairs of images of the set, the landmarks between first and second images of the pair are paired, and the second image is deformed to match the landmarks in that second image with the landmarks in the first image thereby providing motion compensation. A remote PPG signal is obtained from a set of the motion-compensated images.