Pixel Information Processing for Skin Sensing
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Solution Overview
Problem
Imaging-based skin sensing systems face challenges in providing reliable measurements due to variations in ambient lighting and relative motion between the subject and the imaging system, leading to unpredictable and unreliable imaging data.
Innovation Solution
A method involving temporally modulated illumination and a computer-implemented process to acquire and combine pixel information from multiple images, using a time delay to overlap acquisition times and cancel out spatial intensity modulation patterns, thereby reducing the effect of ambient lighting and motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image processing techniques are implemented to determine skin information, then measurement capability is improved, but measurement reliability deteriorates due to relative motion between subject and imaging system
Solution Approach 1:
The patent applies periodic action by using temporally modulated illumination that cycles through different intensity levels. Multiple images are captured at different phases of this modulation cycle, allowing the system to separate ambient lighting effects from the actual skin reflectance properties. This periodic illumination approach enables reliable skin sensing even in the presence of relative motion between the subject and imaging system.
2Object-affected harmful factors
If multiple images are acquired with time delay to reduce ambient lighting effects, then ambient light reduction is improved, but image quality deteriorates due to spatial intensity modulation patterns
Solution Approach 1:
The patent employs feedback by using the spatial intensity modulation patterns observed in the captured images to inform the reconstruction process. The system measures these patterns caused by the interaction between temporally modulated illumination and rolling shutter acquisition, then uses this information to correct and cancel out the artifacts during image reconstruction, thereby maintaining high image quality while effectively reducing ambient lighting effects.
Solution Approach 2:
The patent applies parameter changes by systematically varying the illumination intensity over time according to a known modulation pattern. By capturing images at different illumination phases and using these parameter variations to reconstruct the final image, the system can separate the desired skin reflectance information from ambient lighting interference and spatial intensity modulation artifacts.
3Adaptability or versatility
If imaging is performed in uncontrolled environments with varying ambient lighting, then accessibility is improved, but measurement reliability deteriorates
Solution Approach 1:
The patent introduces an intermediary approach by using temporally modulated illumination as a controlled reference signal that mediates between the uncontrolled ambient lighting environment and the measurement process. This active illumination reference allows the system to distinguish and separate ambient lighting variations from the actual skin properties being measured, enabling reliable measurements in previously unusable uncontrolled environments.
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 allows for robust ambient light reduction and correction, achieving reliable imaging with improved image quality and reduced artifacts from relative motion, suitable for skin sensing applications.
Implementation Method 1
receiving pixel information corresponding to at least part of a first, second and third image of a subject illuminated by temporally modulated illumination
Implementation Method 2
A first, second and third image of a subject are acquired by an imaging system
Data Source
AI summary
In an embodiment, a method (100) is described. The method is a computer-implemented method. The method comprises receiving (102) pixel information corresponding to at least part of a first, second and third image, acquired by an imaging system, of a subject illuminated by temporally modulated illumination. A time delay between an acquisition start time of the first, second and third images is such that there is an overlap in time during acquisition of the first, second and third images. The method further comprises determining (104) modified pixel information for constructing a modified image of the subject. The modified pixel information is determined based on: a difference between the received pixel information of the first, second and third images to reduce an effect of ambient lighting in the received pixel information; and a combination of the received pixel information to cancel out a spatial intensity modulation pattern apparent in each of the first, second and third images. The spatial intensity modulation pattern is due to a timing relationship between an imaging time period over which the imaging system acquires each image and a modulation time period of the temporally modulated illumination.