Non-visible Illumination Scheme for Mobile Devices
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Solution Overview
Problem
Mobile devices with non-visible light sources, such as infrared, consume excessive power due to inefficient illumination schemes, leading to shorter battery life, especially when only a part of the image requires non-visible light for functions like identity verification.
Innovation Solution
A smart illumination scheme that uses a color filter array with dual-band and single-band filters to capture full-resolution images at non-visible wavelengths, adjusting exposure time and activating the non-visible light source only during the necessary part of the image capture process to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the non-visible light source is activated continuously to ensure full-resolution image capture at non-visible wavelengths, then image quality is improved, but power consumption increases
Solution Approach 1:
The non-visible light source is activated periodically only during the specific time interval when the rolling shutter captures the region of interest, rather than continuously. This pulsed illumination synchronized with the shutter timing provides sufficient light for non-visible wavelength capture while dramatically reducing overall power consumption.
Solution Approach 2:
The system first captures a visible light image to identify the region of interest before activating the non-visible light source. This preliminary action allows the system to pre-determine where non-visible illumination is needed, enabling targeted activation of the light source only for the necessary duration and area.
2Area of stationary object
If the non-visible light source illuminates the entire image area to ensure complete coverage, then image capture completeness is improved, but power consumption increases
Solution Approach 1:
The illumination is made non-uniform by directing the non-visible light source to illuminate only the specific region of interest identified in the visible light image, rather than uniformly illuminating the entire image area. This localized illumination approach reduces the total energy required while maintaining complete coverage of the relevant area.
Solution Approach 2:
The image capture process is segmented into different regions: the region of interest that requires non-visible illumination and the rest of the image area that does not. By separating the illumination requirements by region, the system activates the non-visible light source only for the necessary segment, reducing overall power consumption.
3Measurement precision
If the exposure time is extended to capture sufficient non-visible light, then image quality is improved, but visible light interference increases
Solution Approach 1:
The exposure timing is synchronized with periodic activation of the non-visible light source. The rolling shutter captures images at specific intervals that coincide with the pulsed non-visible illumination, allowing sufficient exposure time for non-visible light capture while the brief pulsing nature minimizes visible light interference from ambient sources.
Solution Approach 2:
The exposure time is made dynamic rather than static, being adjusted based on the specific requirements of each region of interest. The rolling shutter enables different exposure durations for different parts of the image, allowing longer exposure where non-visible light is present while using shorter exposure in other areas to reduce visible light interference.
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 significantly reduces power consumption by limiting non-visible light source usage to the required duration and area, enhancing image capture efficiency while maintaining image quality for applications like identity verification.
Implementation Method 1
A non-visible illumination scheme is provided that uses a color filter array with dual-band and single-band filters to capture full-resolution images at non-visible wavelengths
Implementation Method 2
An apparatus, system and method are provided for a non-visible illumination scheme that improves image capture while decreasing power consumption
Data Source
AI summary
Embodiments of an apparatus and process are described. The process includes capturing a first image frame using an image sensor, the image sensor including a pixel array comprising a plurality of pixels arranged in rows and columns and a color filter array optically coupled to the pixel array. A region of interest within the first image frame is determined, and the exposure time of the image sensor is adjusted to eliminate a substantial fraction of the visible light captured by the image sensor. A rolling shutter procedure is used with the pixel array to capture at least one subsequent frame using the adjusted exposure time, and a source of invisible radiation is activated while the rolling shutter enters the region of interest and deactivated when the rolling shutter exits the region of interest. Finally, an image of the region of interest is output. Other embodiments are disclosed and claimed.