Shadow Removal via Visible and Infrared Image Comparison
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Solution Overview
Problem
Existing image capture systems face challenges in effectively reducing shadows in images, particularly under uneven lighting conditions, which degrades image quality and legibility, especially when capturing written content outdoors or in bright sunlight.
Innovation Solution
An information handling system equipped with a processor and multiple sensors, including a visible-light sensor and an active infrared sensor, compares visible-light and infrared images to identify and remove shadow regions by using a shadow mask and depth information to distinguish between shadows and non-shadows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure levels in high-dynamic range (HDR) are adjusted to capture shadow areas, then shadow visibility is improved, but over-exposure or under-exposure occurs in other regions
Solution Approach 1:
The patent introduces an infrared image as an intermediary to detect shadow regions. By comparing visible-light and infrared images, the system identifies shadow areas without directly manipulating visible-light exposure, thereby avoiding over/under-exposure while still achieving shadow region enhancement through selective processing based on the shadow mask.
2Measurement precision
If multiple sensors and processing steps are added to accurately detect and remove shadows, then shadow detection accuracy is improved, but system complexity increases
Solution Approach 1:
The patent uses an infrared image (a copy in a different spectral band) to detect shadow regions in the visible-light image. This copying approach allows accurate shadow detection without requiring complex multi-sensor arrays or sophisticated processing algorithms, as the infrared image naturally captures shadow information that can be directly compared to the visible image.
3Manufacturing precision
If shadow regions are removed or reduced in the visible-light image, then image quality and legibility are improved, but the distinction between shadows and non-shadows becomes more difficult
Solution Approach 1:
The patent transitions from analyzing only the visible-light image (two-dimensional intensity data) to comparing it with an infrared image (adding a spectral dimension). This dimensional change provides additional information about shadow regions, making it easier to distinguish shadows from non-shadows and enabling more accurate shadow removal while preserving true object boundaries.
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 enhances image quality by accurately detecting and reducing shadows, improving legibility and readability of content in images, even under challenging lighting conditions.
Implementation Method 1
receive an infrared image from an active infrared sensor
Data Source
AI summary
In accordance with embodiments of the present disclosure, an information handling system may include a processor and a non-transitory computer-readable medium embodying a program of instructions. The program of instructions may be configured to, when read and executed by the processor, receive a visible-light image from a visible-light sensor, receive an infrared image from an active infrared sensor, and compare the visible-light image to the infrared image to determine shadow regions of the visible-light image having shadows.