Remote Facial Physiological Sensing With Motion-Filtered Index Correction
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Solution Overview
Problem
Video-based remote measurement of physiological indices is prone to inaccuracies due to motion artifacts and environmental factors, leading to inconsistent and distorted measurements in remote polygraph tests.
Innovation Solution
A method and system that corrects physiological indices by monitoring face movements and environmental conditions, using a multi-layer Kalman filter and L1 norm-based smoothing to ensure consistency and accuracy, and provides these indices as input to a remote polygraph test system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If video-based remote measurement is used to determine physiological indices, then the measurement can be performed remotely without contact, but the measurement accuracy deteriorates due to motion artifacts and environmental factors
Solution Approach 1:
The patent introduces multiple intermediary components: (1) a face region detector that isolates the face from the video stream, (2) a motion detector that identifies and flags frames with excessive motion, and (3) a physiological index determiner that selectively processes only valid frames. These intermediaries filter out corrupted data caused by motion artifacts and environmental factors, resolving the contradiction between remote measurement ease and measurement precision.
2Productivity
If all video frames are processed to determine physiological indices, then the productivity is high, but the reliability deteriorates due to inclusion of invalid frames with motion artifacts
Solution Approach 1:
The patent applies preliminary action by performing motion detection and frame validation before physiological index determination. The motion detector pre-processes each video frame to identify invalid frames with excessive motion artifacts, and the physiological index determiner then selectively processes only the valid frames. This preliminary filtering ensures that only reliable data is used for measurement, maintaining both productivity and reliability.
3Measurement precision
If motion artifacts are corrected to improve measurement accuracy, then the measurement precision improves, but the device complexity increases due to additional processing requirements
Solution Approach 1:
The patent applies the extraction principle by isolating and removing problematic elements rather than attempting to correct them. The motion detector identifies frames with motion artifacts, and these invalid frames are extracted and excluded from processing. Instead of implementing complex correction algorithms, the system simply removes the corrupted data and processes only clean frames, thereby improving precision without significantly increasing 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
Improves the accuracy of remote physiological index determination by ensuring corrected indices reflect a consistent physiological condition, enhancing the performance of remote polygraph tests in distinguishing truthful or deceptive responses.
Implementation Method 1
Video-based remote measurement of physiological indices may be performed by capturing a video of a face of a subject and analyzing variations in time of skin color caused by blood volume changes
Data Source
AI summary
A method of determining physiological indices for a remote polygraph test, which may include, using a computing device operating a processor: receiving a video of a face of a subject; based on the video, monitoring a plurality of physiological indices of the subject; and based on values of the monitored physiological indices and a physiological correlation between the monitored physiological indices, determining a plurality of corrected physiological indices, the corrected physiological indices having values that are consistent with each other to reflect a consistent physiological condition of the subject.